{"kind": "tool", "major": "18", "item": {"slug": "pg-checksums", "name": "pg_checksums", "name_zh": "", "category": "Server applications", "summary": "pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster", "aliases": ["pg_checksums"], "content_hash": "66b6d0a99982350e948adee238f9c25b29aef70d8455235184b771718a1b703d", "versions": {"12": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "12.22"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "10"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/12/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "title": "Environment variables", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Meaning"}]}], "options": [{"names": ["-D directory", "--pgdata= directory"], "summary": "Specifies the directory where the database cluster is stored.", "signature": "-D directory --pgdata= directory", "source_url": "/docs/12/app-pgchecksums.html", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": "-c --check", "source_url": "/docs/12/app-pgchecksums.html", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/12/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/12/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/12/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/12/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/12/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/12/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/12/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/12/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "label": "12.22", "major": "12", "channel": "historical", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/12/postgresql-12-A4.pdf", "bytes": 13424351, "pages": 2803, "sha256": "7422cf53fd1939e7a3d2925231a88b0330e468afa5393627cac0ff86158a0621", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/12/postgresql-12-US.pdf", "bytes": 13322565, "pages": 2958, "sha256": "51f3b04e72907fc38512685946223452ea65f84419c60c66241dfa3396035e77", "built_at": "2026-09-26"}}, "tree": "12", "index": "index.html", "major": "12", "pages": 1131, "release": "12.22", "source_url": "https://ftp.postgresql.org/pub/source/v12.22/postgresql-12.22.tar.bz2", "svg_assets": 2, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "revision": "7a827e97cbfacd7febff75f34443e2043e40723de5b6d8c9d81a9430b65a37e4", "evidence_kind": "English manual and source declarations", "source_sha256": "8df3c0474782589d3c6f374b5133b1bd14d168086edbc13c6e72e67dd4527a3b"}, "sources": [{"url": "/docs/12/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "12.22 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "227bd278a0a1c348be37b328077beac0126143b03db30c9de7bbd1b2e47cbbd6"}, {"url": "/docs/12/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "7f6ae1fadc1b0bffa606551460e62aacdc2508a3fb66566ddae861928ca6080b"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, every file in the cluster is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "signature": "-V --version", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "signature": "-? --help", "description": "Show help about pg_checksums command line arguments, and exit."}], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}]}, "comparison_hash": "dc177d5e3b70222dba48a916063353fd7bd6e09a1784594b268608ed54ea9e7a"}, "13": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "13.23"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "10"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/13/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "title": "Environment variables", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Meaning"}]}], "options": [{"names": ["-D directory", "--pgdata= directory"], "summary": "Specifies the directory where the database cluster is stored.", "signature": "-D directory --pgdata= directory", "source_url": "/docs/13/app-pgchecksums.html", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": "-c --check", "source_url": "/docs/13/app-pgchecksums.html", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/13/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/13/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/13/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/13/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/13/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/13/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/13/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/13/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "label": "13.23", "major": "13", "channel": "historical", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/13/postgresql-13-A4.pdf", "bytes": 13843239, "pages": 2826, "sha256": "171cc09f90936dbc1cbd503a98ff07ae72ea58ab9771ff051313f1217737799c", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/13/postgresql-13-US.pdf", "bytes": 13739572, "pages": 2984, "sha256": "48d09c6e197d9db4220f41afe83efe848a8661b1b168d3b89419751ecaf6c24d", "built_at": "2026-09-26"}}, "tree": "13", "index": "index.html", "major": "13", "pages": 1139, "release": "13.23", "source_url": "https://ftp.postgresql.org/pub/source/v13.23/postgresql-13.23.tar.bz2", "svg_assets": 3, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "revision": "614ee3133270254e476c118cdf6f72af78d4e4b8bbd9b28ed9ab1e14e4e9c0f6", "evidence_kind": "English manual and source declarations", "source_sha256": "6ec3c82726af92b7dec873fa1cdf881eca92a4219787dfad05acb6b10e041fd6"}, "sources": [{"url": "/docs/13/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "13.23 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "bbcd9ada6cdeebe1cf403334d113915cee5081cc4583e4dff5c39a16cfaa427d"}, {"url": "/docs/13/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "074ef8577fd368272a2360309e1226e2d0b1e570a3e1da62dfcca63ac9ee5539"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, every file in the cluster is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "signature": "-V --version", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "signature": "-? --help", "description": "Show help about pg_checksums command line arguments, and exit."}], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}]}, "comparison_hash": "dc177d5e3b70222dba48a916063353fd7bd6e09a1784594b268608ed54ea9e7a"}, "14": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "14.24"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "10"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/14/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "title": "Environment variables", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Meaning"}]}], "options": [{"names": ["-D directory", "--pgdata= directory"], "summary": "Specifies the directory where the database cluster is stored.", "signature": "-D directory --pgdata= directory", "source_url": "/docs/14/app-pgchecksums.html", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": "-c --check", "source_url": "/docs/14/app-pgchecksums.html", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/14/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/14/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/14/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/14/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/14/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/14/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/14/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/14/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "label": "14.24", "major": "14", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/14/postgresql-14-A4.pdf", "bytes": 14354704, "pages": 2944, "sha256": "8bc6b9dd7b246888bb77f0a5e8c39a2eae52e9926569832669c7d1600becb27c", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/14/postgresql-14-US.pdf", "bytes": 14242178, "pages": 3102, "sha256": "b7ecb5a5f62d8b9f73a69e25a7d26ba285373bc53168a553bff7b77955506db4", "built_at": "2026-09-26"}}, "tree": "14", "index": "index.html", "major": "14", "pages": 1158, "release": "14.24", "source_url": "https://ftp.postgresql.org/pub/source/v14.24/postgresql-14.24.tar.bz2", "svg_assets": 3, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "revision": "588700d46356d8837c77c7c0a4e71e645fe6535983b8f1830aa8f2e4e41c40ae", "evidence_kind": "English manual and source declarations", "source_sha256": "a7fa7ed3d558172355f51406097a7bd4f6b473be80f311ef7cda96bf383d8897"}, "sources": [{"url": "/docs/14/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "14.24 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "54c52f23b0e8a506574a9ee17afd63fa50ca361f0ddd064f188b7870953bb812"}, {"url": "/docs/14/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "db0cdccaa8d3c65ad3b2a07d4956eb5a783a18505bfa0f9d9626eef4ab94fe44"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, every file in the cluster is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "signature": "-V --version", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "signature": "-? --help", "description": "Show help about pg_checksums command line arguments, and exit."}], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}]}, "comparison_hash": "dc177d5e3b70222dba48a916063353fd7bd6e09a1784594b268608ed54ea9e7a"}, "15": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "15.19"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "10"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/15/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "title": "Environment variables", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Meaning"}]}], "options": [{"names": ["-D directory", "--pgdata= directory"], "summary": "Specifies the directory where the database cluster is stored.", "signature": "-D directory --pgdata= directory", "source_url": "/docs/15/app-pgchecksums.html", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": "-c --check", "source_url": "/docs/15/app-pgchecksums.html", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/15/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/15/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/15/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/15/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/15/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/15/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/15/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/15/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "label": "15.19", "major": "15", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/15/postgresql-15-A4.pdf", "bytes": 14609140, "pages": 2987, "sha256": "66228564a4d16efb47d6a914085716ecfe22ca1566db56bc7c3d82f790646d72", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/15/postgresql-15-US.pdf", "bytes": 14495690, "pages": 3153, "sha256": "645a498c2390d47a6223ec74770631185807a19c484edb0fc5a295d9f460bc02", "built_at": "2026-09-26"}}, "tree": "15", "index": "index.html", "major": "15", "pages": 1168, "release": "15.19", "source_url": "https://ftp.postgresql.org/pub/source/v15.19/postgresql-15.19.tar.bz2", "svg_assets": 3, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "revision": "6af958c6520151fc7697d56e0616b03fb00522c4568158674d452ae0644ba545", "evidence_kind": "English manual and source declarations", "source_sha256": "e1a64a87a46b825b88c082e4518161a47aab53c45694964f8ba1df28f7859f89"}, "sources": [{"url": "/docs/15/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "15.19 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "2c83df8804201a1d1b6fc7dab1ca63871686b1a01ce0d735c580bbceff800b66"}, {"url": "/docs/15/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "1240cfbb13ebfd22aac8d5ae40c62a9015b246f7774bcf0bce97355ce06350a0"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "signature": "-V --version", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "signature": "-? --help", "description": "Show help about pg_checksums command line arguments, and exit."}], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}]}, "comparison_hash": "dc177d5e3b70222dba48a916063353fd7bd6e09a1784594b268608ed54ea9e7a"}, "16": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "16.15"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "10"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/16/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "title": "Environment variables", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Meaning"}]}], "options": [{"names": ["-D directory", "--pgdata= directory"], "summary": "Specifies the directory where the database cluster is stored.", "signature": "-D directory --pgdata= directory", "source_url": "/docs/16/app-pgchecksums.html", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": "-c --check", "source_url": "/docs/16/app-pgchecksums.html", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/16/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/16/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/16/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/16/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/16/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/16/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/16/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/16/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "label": "16.15", "major": "16", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/16/postgresql-16-A4.pdf", "bytes": 15282337, "pages": 3055, "sha256": "4bb6c1f63deedac98736d8c4c7bc0fad0ac24e85b07e21ee10411872f06afd06", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/16/postgresql-16-US.pdf", "bytes": 15164148, "pages": 3220, "sha256": "5b6b6166c89991199e144bb0ae34c17a5f29826251dbf19db1abc0df3a3e771b", "built_at": "2026-09-26"}}, "tree": "16", "index": "index.html", "major": "16", "pages": 1169, "release": "16.15", "source_url": "https://ftp.postgresql.org/pub/source/v16.15/postgresql-16.15.tar.bz2", "svg_assets": 3, "source_mode": "en HTML verified against the pinned official archive", "source_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "revision": "3c21e58b35318021716440e67bb8bafd392b6a2b965a244d90e9e33c99e0bdef", "evidence_kind": "English manual and source declarations", "source_sha256": "c1575341fa7bd40f5274ea465b34390f4dc64cdd0770af327005caaeb9f6b7ed"}, "sources": [{"url": "/docs/16/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "16.15 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "36e362f6ae0915dd10a98609d98a51e9dfe832d2f4a3ac45c1304de3627d4618"}, {"url": "/docs/16/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "8aaa4422eece8f26d84715f855d9d0f7f87b200f8b82898c73c865ee42c2c70f"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "signature": "-V --version", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "signature": "-? --help", "description": "Show help about pg_checksums command line arguments, and exit."}], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}]}, "comparison_hash": "dc177d5e3b70222dba48a916063353fd7bd6e09a1784594b268608ed54ea9e7a"}, "17": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "17.11"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "11"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "--sync-method= method"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/17/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "title": "Environment variables", "columns": [{"key": "name", "label": "Variable"}, {"key": "description", "label": "Meaning"}]}], "options": [{"names": ["-D directory", "--pgdata= directory"], "summary": "Specifies the directory where the database cluster is stored.", "signature": "-D directory --pgdata= directory", "source_url": "/docs/17/app-pgchecksums.html", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": "-c --check", "source_url": "/docs/17/app-pgchecksums.html", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/17/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/17/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/17/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/17/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/17/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["--sync-method= method"], "summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": "--sync-method= method", "source_url": "/docs/17/app-pgchecksums.html", "description": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace. On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/17/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/17/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/17/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "label": "17.11", "major": "17", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/17/postgresql-17-A4.pdf", "bytes": 15521293, "pages": 3099, "sha256": "1991354df0dc89e70ec39328c28988ef8b19c6a93671dab3893650b63e9f4e36", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/17/postgresql-17-US.pdf", "bytes": 15398150, "pages": 3270, "sha256": "07696c8f38abf31babf22d2db337093936e7c472d2af36d050b000c49bbcf52c", "built_at": "2026-09-26"}}, "tree": "17", "index": "index.html", "major": "17", "pages": 1143, "release": "17.11", "source_url": "https://ftp.postgresql.org/pub/source/v17.11/postgresql-17.11.tar.bz2", "svg_assets": 3, "source_mode": "en SGML built with pinned official archive", "source_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "revision": "58419c9b0dd42cb34c8d53695bb025a7e582edf55ccd4c5bcb1c2c7c71a37487", "evidence_kind": "English manual and source declarations", "source_sha256": "dd27f2b3c59e73ed14aa3324901242bf69a032a6347805f274e6260322d42979"}, "sources": [{"url": "/docs/17/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "17.11 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "088d4d799d0334e62132c19aff06daacb91becddfe984848ff5df2f73b68a31e"}, {"url": "/docs/17/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "01f07993ff020684f4c290d17cdafa26fb17ea5c1d476bc3a5efc68bf8ddd9b9"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
--sync-method=method
\n
\n

When set to fsync, which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.

\n

On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs.

\n

This option has no effect when --no-sync is used.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["--sync-method= method"], "signature": "--sync-method= method", "description": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace. On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "signature": "-V --version", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "signature": "-? --help", "description": "Show help about pg_checksums command line arguments, and exit."}], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}]}, "comparison_hash": "9df98d0a65050d461414d0c4fc42b1f97bbb808ec68690d4aad884d9b571bb05"}, "18": {"facts": [{"label": "Documented executable", "value": "pg_checksums"}, {"label": "Executable version", "value": "18.6"}, {"label": "Reference inventory", "value": "Server applications"}, {"label": "Option definition groups", "value": "11"}], "tables": [{"key": "options", "rows": [{"summary": "Specifies the directory where the database cluster is stored.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-D directory --pgdata= directory"}}, {"summary": "Checks checksums. This is the default mode if nothing else is specified.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "--sync-method= method"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/18/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. 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This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/18/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/18/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/18/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/18/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/18/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["--sync-method= method"], "summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": "--sync-method= method", "source_url": "/docs/18/app-pgchecksums.html", "description": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace. On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/18/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/18/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/18/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "label": "18.6", "major": "18", "channel": "stable", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/18/postgresql-18-A4.pdf", "bytes": 15865106, "pages": 3154, "sha256": "19512c405da53f9f7fcf0abba359223aa65f021be025bf3411381918f92e3190", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/18/postgresql-18-US.pdf", "bytes": 15748059, "pages": 3328, "sha256": "facbe6c229e598b872d3d98bef53308f46e06746006fa4590de9a7de9dd46319", "built_at": "2026-09-26"}}, "tree": "18", "index": "index.html", "major": "18", "pages": 1148, "release": "18.6", "source_url": "https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2", "svg_assets": 3, "source_mode": "en SGML built with pinned official archive", "source_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "revision": "ee8d1a3612338fd9adf250730cb640fcc5233b5491337cc00a316a44e3a0b9f8", "evidence_kind": "English manual and source declarations", "source_sha256": "555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f"}, "sources": [{"url": "/docs/18/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "18.6 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "b16216257df55c09f6cc76f43a9c8ac811fda49b3a4490608f936681aa3cd4c2"}, {"url": "/docs/18/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "e9f8bbcc8e3641fadd1d20991e8aad6b532155b786ba5a1b7b364ec4f1a5bef3"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
--sync-method=method
\n
\n

When set to fsync, which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.

\n

On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs.

\n

This option has no effect when --no-sync is used.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
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On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. 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This is the default mode if nothing else is specified.", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-c --check"}}, {"summary": "Disables checksums.", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-d --disable"}}, {"summary": "Enables checksums.", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-e --enable"}}, {"summary": "Only validate checksums in the relation with filenode filenode .", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-f filenode --filenode= filenode"}}, {"summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. 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Lists all checked files.", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/19/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. 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This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/19/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/19/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/19/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/19/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/19/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["--sync-method= method"], "summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": "--sync-method= method", "source_url": "/docs/19/app-pgchecksums.html", "description": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace. On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/19/app-pgchecksums.html", "description": "Enable verbose output. Lists all checked files."}, {"names": ["-V", "--version"], "summary": "Print the pg_checksums version and exit.", "signature": "-V --version", "source_url": "/docs/19/app-pgchecksums.html", "description": "Print the pg_checksums version and exit."}, {"names": ["-?", "--help"], "summary": "Show help about pg_checksums command line arguments, and exit.", "signature": "-? --help", "source_url": "/docs/19/app-pgchecksums.html", "description": "Show help about pg_checksums command line arguments, and exit."}], "related": [], "release": {"ref": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "label": "19beta4", "major": "19", "channel": "preview", "manifest": {"pdf": {"A4": {"url": "/files/documentation/pdf/19/postgresql-19-A4.pdf", "bytes": 16064841, "pages": 3052, "sha256": "4dd099e4125c591128fc5f3ebd02178dc24781f9e5ae629f96d67c4c8547427b", "built_at": "2026-09-26"}, "US": {"url": "/files/documentation/pdf/19/postgresql-19-US.pdf", "bytes": 15974616, "pages": 3225, "sha256": "61971fa857f0956d47341a0388fa6af9ae10acf691d4b2fc009007d384b0342b", "built_at": "2026-09-26"}}, "tree": "19", "index": "index.html", "major": "19", "pages": 1155, "release": "19beta4", "source_url": "https://ftp.postgresql.org/pub/source/v19beta4/postgresql-19beta4.tar.bz2", "svg_assets": 5, "source_mode": "en SGML built with pinned official archive", "source_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, "revision": "1bbbbf4133d426f0e4304010688d2984c30fb67df0cc3a61b3e37eb3f6f37833", "evidence_kind": "English manual and source declarations", "source_sha256": "83157ee9c599d03b2f7a3d73ef3a56ec24e0e79cc2b3501a64d1364f56398c86"}, "sources": [{"url": "/docs/19/app-pgchecksums.html", "file": "app-pgchecksums.html", "label": "19beta4 English manual \u00b7 app-pgchecksums.html", "anchor": "", "sha256": "dd9067d67ff9ed5993cf25f73b71d393f56a7d0ab93ec23873e2ef2c5a83f96d"}, {"url": "/docs/19/reference-server.html", "file": "reference-server.html", "label": "Server applications inventory", "anchor": "", "sha256": "425b070323b448b5516d2cb4e9e4ac77efb5d19dd4e8005d0ae1c61db9ec78e6"}], "sections": [], "synopsis": ["pg_checksums [ option ...] [ [ -D | --pgdata ] datadir ]"], "signature": "pg_checksums [ option ...] [ [ -D | --pgdata ] datadir ]", "description": ["pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster"], "environment": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [ [ -D | --pgdata ] datadir ]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. See Section\u00a028.2 for further details on data checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D datadir
--pgdata=datadir
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
--sync-method=method
\n
\n

When set to fsync, which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.

\n

On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs.

\n

This option has no effect when --no-sync is used.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n

The target cluster must have the same major version as pg_checksums.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D datadir", "--pgdata= datadir"], "signature": "-D datadir --pgdata= datadir", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "signature": "-P --progress", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["--sync-method= method"], "signature": "--sync-method= method", "description": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace. On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. 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This option has no effect when using --check .", "signature": {"url": "/docs/devel/app-pgchecksums.html", "text": "-N --no-sync"}}, {"summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": {"url": "/docs/devel/app-pgchecksums.html", "text": "-P --progress"}}, {"summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": {"url": "/docs/devel/app-pgchecksums.html", "text": "--sync-method= method"}}, {"summary": "Enable verbose output. Lists all checked files.", "signature": {"url": "/docs/devel/app-pgchecksums.html", "text": "-v --verbose"}}, {"summary": "Print the pg_checksums version and exit.", "signature": {"url": "/docs/devel/app-pgchecksums.html", "text": "-V --version"}}, {"summary": "Show help about pg_checksums command line arguments, and exit.", "signature": {"url": "/docs/devel/app-pgchecksums.html", "text": "-? --help"}}], "title": "Documented options", "columns": [{"key": "signature", "label": "Option and arguments"}, {"key": "summary", "label": "Description"}]}, {"key": "environment", "rows": [{"name": "PGDATA", "description": "Specifies the directory where the database cluster is stored; can be overridden using the -D option."}, {"name": "PG_COLOR", "description": "Specifies whether to use color in diagnostic messages. 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This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "summary": "Disables checksums.", "signature": "-d --disable", "source_url": "/docs/devel/app-pgchecksums.html", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "summary": "Enables checksums.", "signature": "-e --enable", "source_url": "/docs/devel/app-pgchecksums.html", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "summary": "Only validate checksums in the relation with filenode filenode .", "signature": "-f filenode --filenode= filenode", "source_url": "/docs/devel/app-pgchecksums.html", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "summary": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .", "signature": "-N --no-sync", "source_url": "/docs/devel/app-pgchecksums.html", "description": "By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check ."}, {"names": ["-P", "--progress"], "summary": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.", "signature": "-P --progress", "source_url": "/docs/devel/app-pgchecksums.html", "description": "Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums."}, {"names": ["--sync-method= method"], "summary": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.", "signature": "--sync-method= method", "source_url": "/docs/devel/app-pgchecksums.html", "description": "When set to fsync , which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace. On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "summary": "Enable verbose output. Lists all checked files.", "signature": "-v --verbose", "source_url": "/docs/devel/app-pgchecksums.html", "description": "Enable verbose output. 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Possible values are always , auto and never ."}], "manual_html": "
\n
\n
\n

pg_checksums

\n

pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

\n
\n
\n

Synopsis

\n
\n

pg_checksums [option...] [ [ -D | --pgdata ] datadir ]

\n
\n
\n
\n

Description

\n

pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. Checksums can also be enabled while the cluster is running using Online Enabling of Checksums processing, see Section\u00a028.2 for further details on the different approaches. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

If checksums were in the process of being enabled or disabled using Online Enabling of Checksums when the cluster was shut down, the control file still records that interrupted state, and pg_checksums refuses to run in any mode. Start the cluster and shut it down cleanly to reset the state, then retry; on a standby, let replication complete the transition first.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

\n
\n
\n

Options

\n

The following command-line options are available:

\n
\n
\n
-D datadir
--pgdata=datadir
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
--sync-method=method
\n
\n

When set to fsync, which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.

\n

On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs.

\n

This option has no effect when --no-sync is used.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
\n

Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

Enabling or disabling checksums with pg_checksums changes only the local data directory; the new state is not replicated to any other node. In a replication setup the same change must be applied to every node:

\n
\n
    \n
  1. \n

    Shut down all nodes

    \n

    All nodes participating in the replication must be stopped with a clean shutdown; pg_checksums refuses to run on a data directory left behind by an immediate shutdown. Before stopping a standby, make sure it has replayed all WAL of the primary: stop the primary first, read its \u201cLatest checkpoint location\u201d with pg_controldata, and check that pg_last_wal_replay_lsn() on the standby has advanced past it. Comparing the replay position with pg_last_wal_receive_lsn() is not enough, as it only shows that the WAL the standby received has been replayed.

    \n
    2. \n
  2. \n

    Enable or disable data checksums on each node

    \n

    Run pg_checksums on the data directory of each node in the replication setup. Nodes can be processed in parallel while they are shut down. Processing must complete successfully on all nodes before continuing.

    \n
    3. \n
  3. \n

    Restart all nodes

    \n

    Start the nodes normally, verify that data_checksums matches on all of them, and monitor the logs of the standbys for data checksum state mismatch warnings.

    \n
    4. \n
\n
\n

The replay requirement in Step 1 exists because an offline change is recorded only in the control file and has no defined ordering against WAL the node has not replayed yet; see Section\u00a028.2.1. A node stopped before replaying an online checksum state change applies that change when it is restarted, overriding the offline change, and the states of the nodes silently diverge until a later checkpoint record triggers the warning described below. Because of this it is best not to mix the two mechanisms: change the state of a replication setup either with the offline procedure above or with an online transition, and make sure the previous change has reached every node before starting the next one.

\n

If the change is applied inconsistently, each node keeps its own state, and a standby logs a warning when the state recorded in the replayed WAL differs from its own. The same warning can appear transiently while a standby catches up over WAL written before a consistent change; it stops once a checkpoint record carrying the new state has been replayed.

\n

A standby whose data directory was never checksummed must not have checksums enabled by catching up this way. Converge the cluster by running pg_checksums on it while stopped as outlined above, by enabling checksums online, or by recreating it from a base backup. Note that an online enable only starts from a primary whose checksums are off, so if they are already enabled there, disable them online first.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n

Tools that copy relation file blocks directly between nodes, such as pg_rewind, require all nodes to be in the same data checksum state, else there is risk for data corruption.

\n

The target cluster must have the same major version as pg_checksums.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D datadir", "--pgdata= datadir"], "signature": "-D datadir --pgdata= datadir", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. 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On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs . This option has no effect when --no-sync is used."}, {"names": ["-v", "--verbose"], "signature": "-v --verbose", "description": "Enable verbose output. 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Possible values are always , auto and never ."}], "manual_html": "
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pg_checksums

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pg_checksums \u2014 enable, disable or check data checksums in a PostgreSQL database cluster

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\n
\n

Synopsis

\n
\n

pg_checksums [option...] [[ -D | --pgdata ]datadir]

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\n
\n
\n

Description

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pg_checksums checks, enables or disables data checksums in a PostgreSQL cluster. The server must be shut down cleanly before running pg_checksums. When verifying checksums, the exit status is zero if there are no checksum errors, and nonzero if at least one checksum failure is detected. When enabling or disabling checksums, the exit status is nonzero if the operation failed.

\n

When verifying checksums, every file in the cluster is scanned. When enabling checksums, each relation file block with a changed checksum is rewritten in-place. Disabling checksums only updates the file pg_control.

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\n
\n

Options

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The following command-line options are available:

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\n
\n
-D directory
--pgdata=directory
\n
\n

Specifies the directory where the database cluster is stored.

\n
\n
-c
--check
\n
\n

Checks checksums. This is the default mode if nothing else is specified.

\n
\n
-d
--disable
\n
\n

Disables checksums.

\n
\n
-e
--enable
\n
\n

Enables checksums.

\n
\n
-f filenode
--filenode=filenode
\n
\n

Only validate checksums in the relation with filenode filenode.

\n
\n
-N
--no-sync
\n
\n

By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check.

\n
\n
-P
--progress
\n
\n

Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.

\n
\n
--sync-method=method
\n
\n

When set to fsync, which is the default, pg_checksums will recursively open and synchronize all files in the data directory. The search for files will follow symbolic links for the WAL directory and each configured tablespace.

\n

On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file systems that contain the data directory, the WAL files, and each tablespace. See recovery_init_sync_method for information about the caveats to be aware of when using syncfs.

\n

This option has no effect when --no-sync is used.

\n
\n
-v
--verbose
\n
\n

Enable verbose output. Lists all checked files.

\n
\n
-V
--version
\n
\n

Print the pg_checksums version and exit.

\n
\n
-?
--help
\n
\n

Show help about pg_checksums command line arguments, and exit.

\n
\n
\n
\n
\n
\n

Environment

\n
\n
\n
PGDATA
\n
\n

Specifies the directory where the database cluster is stored; can be overridden using the -D option.

\n
\n
PG_COLOR
\n
\n

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

\n
\n
\n
\n
\n
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Notes

\n

Enabling checksums in a large cluster can potentially take a long time. During this operation, the cluster or other programs that write to the data directory must not be started or else data loss may occur.

\n

When using a replication setup with tools which perform direct copies of relation file blocks (for example pg_rewind), enabling or disabling checksums can lead to page corruptions in the shape of incorrect checksums if the operation is not done consistently across all nodes. When enabling or disabling checksums in a replication setup, it is thus recommended to stop all the clusters before switching them all consistently. Destroying all standbys, performing the operation on the primary and finally recreating the standbys from scratch is also safe.

\n

If pg_checksums is aborted or killed while enabling or disabling checksums, the cluster's data checksum configuration remains unchanged, and pg_checksums can be re-run to perform the same operation.

\n
\n
", "manual_path": "app-pgchecksums.html", "comparison_data": {"options": [{"names": ["-D directory", "--pgdata= directory"], "signature": "-D directory --pgdata= directory", "description": "Specifies the directory where the database cluster is stored."}, {"names": ["-c", "--check"], "signature": "-c --check", "description": "Checks checksums. This is the default mode if nothing else is specified."}, {"names": ["-d", "--disable"], "signature": "-d --disable", "description": "Disables checksums."}, {"names": ["-e", "--enable"], "signature": "-e --enable", "description": "Enables checksums."}, {"names": ["-f filenode", "--filenode= filenode"], "signature": "-f filenode --filenode= filenode", "description": "Only validate checksums in the relation with filenode filenode ."}, {"names": ["-N", "--no-sync"], "signature": "-N --no-sync", "description": "By default, pg_checksums will wait for all files to be written safely to disk. 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This is the default mode if nothing else is specified.\",\n+ \"names\": [\n+ \"-c\",\n+ \"--check\"\n+ ],\n+ \"signature\": \"-c --check\"\n+ },\n+ {\n+ \"description\": \"Disables checksums.\",\n+ \"names\": [\n+ \"-d\",\n+ \"--disable\"\n+ ],\n+ \"signature\": \"-d --disable\"\n+ },\n+ {\n+ \"description\": \"Enables checksums.\",\n+ \"names\": [\n+ \"-e\",\n+ \"--enable\"\n+ ],\n+ \"signature\": \"-e --enable\"\n+ },\n+ {\n+ \"description\": \"Only validate checksums in the relation with filenode filenode .\",\n+ \"names\": [\n+ \"-f filenode\",\n+ \"--filenode= filenode\"\n+ ],\n+ \"signature\": \"-f filenode --filenode= filenode\"\n+ },\n+ {\n+ \"description\": \"By default, pg_checksums will wait for all files to be written safely to disk. This option causes pg_checksums to return without waiting, which is faster, but means that a subsequent operating system crash can leave the updated data directory corrupt. Generally, this option is useful for testing but should not be used on a production installation. This option has no effect when using --check .\",\n+ \"names\": [\n+ \"-N\",\n+ \"--no-sync\"\n+ ],\n+ \"signature\": \"-N --no-sync\"\n+ },\n+ {\n+ \"description\": \"Enable progress reporting. Turning this on will deliver a progress report while checking or enabling checksums.\",\n+ \"names\": [\n+ \"-P\",\n+ \"--progress\"\n+ ],\n+ \"signature\": \"-P --progress\"\n+ },\n+ {\n+ \"description\": \"Enable verbose output. Lists all checked files.\",\n+ \"names\": [\n+ \"-v\",\n+ \"--verbose\"\n+ ],\n+ \"signature\": \"-v --verbose\"\n+ },\n+ {\n+ \"description\": \"Print the pg_checksums version and exit.\",\n+ \"names\": [\n+ \"-V\",\n+ \"--version\"\n+ ],\n+ \"signature\": \"-V --version\"\n+ },\n+ {\n+ \"description\": \"Show help about pg_checksums command line arguments, and exit.\",\n+ \"names\": [\n+ \"-?\",\n+ \"--help\"\n+ ],\n+ \"signature\": \"-? --help\"\n+ }\n+ ],\n+ \"synopsis\": [\n+ \"pg_checksums [ option ...] [[ -D | --pgdata ] datadir ]\"\n+ ]\n+}"}}