{"Entry":{"collection":"guc","key":"data_checksums","name":"data_checksums","aliases":[],"metadata":{"baseline":false,"boot_human":"Not specified","boot_val":null,"category":"Preset Options","category_zh":"","changed_in":[],"changes":[{"documentation_changed":false,"fields":{},"from":"9.2","status":"added","to":"9.3"},{"documentation_changed":true,"fields":{},"from":"17","status":"changed","to":"18"},{"documentation_changed":true,"fields":{},"from":"18","status":"changed","to":"19"},{"documentation_changed":true,"fields":{},"from":"19","status":"changed","to":"20"}],"content_hash":"ba99491bc8e242212501e74d3871249e8740317615715599d4296f8622fc21b6","context":"","default_changed_in":[],"default_history":[{"from":"9.3","to":"19","value":"off"}],"derived_content_hash":"7fd5f2f0f019ec14aa0a05943da36419d22f6a96d2def22ccab1864426874c4f","editorial":{"advice":{"olap":"Budget the checksum CPU and full-cluster enable/disable scan on the actual dataset. Verify backup and replica compatibility before the offline transition.","oltp":"Treat the value as an integrity capability, not a performance knob. Prefer checksums for persistent clusters and monitor checksum failures; use a planned offline pg_checksums procedure for an existing cluster.","small":"Enable at initdb when possible. For an existing small cluster, pg_checksums is usually simpler than a rebuild, but still requires shutdown and a recoverable backup."},"mechanism":["Reports the cluster-wide data-checksum state stored in the control file. It is internal/read-only in SQL and cannot be changed with SET.","Checksums are chosen by initdb or changed later with the server stopped by pg_checksums. PostgreSQL verifies page checksums when reading from storage and computes them when writing pages.","A checksum detects a torn or corrupted page; it does not repair it or prove that WAL, backups, memory, and every storage layer are healthy. Changes require an offline procedure, capacity for a full-cluster scan, and a verified backup."],"pitfalls":["Trying to change the read-only report with SET or ALTER SYSTEM.","Running pg_checksums while the server is not cleanly shut down.","Treating a checksum failure as repairable by ignoring the error.","Assuming checksums validate WAL records, logical correctness, or backups by themselves.","Enabling checksums without monitoring checksum failures and storage health."],"references":[{"title":"PostgreSQL 19 Beta 4: data_checksums","url":"https://www.postgresql.org/docs/19/runtime-config-preset.html#GUC-DATA-CHECKSUMS"},{"title":"PostgreSQL 19 release notes","url":"https://www.postgresql.org/docs/19/release-19.html"}],"related":["ignore_checksum_failure","zero_damaged_pages","wal_log_hints","full_page_writes","data_directory","block_size"],"summary":"data_checksums — Shows whether data checksums are turned on for this cluster. Observed in PG9.3–19 Beta 4; its last measured boot default is off in PG19 Beta 4, with internal context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA."},"enumvals":[],"first_version":"9.3","group":"Preset Options","group_slug":"preset","imported_at":"2026-09-27T17:57:31.008115+08:00","intro_commit":{"authored_at":"2013-09-16T14:36:01+03:00","discussion":[],"hash":"5a7e75849cb595943fc605c4532716e9dd69f8a0","subject":"Add a GUC to report whether data page checksums are enabled.","url":"https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=5a7e75849cb595943fc605c4532716e9dd69f8a0"},"key":"data_checksums","last_version":"20","max_val":"","min_val":"","name":"data_checksums","position":76,"present_in":["9.3","9.4","9.5","9.6","10","11","12","13","14","15","16","17","18","19","20"],"repair_provenance":{"original_source_revision":"english-manuals:81608db6c9fa689a62a0fa69c5ab43b207f83bc466f0dc234aa59289c7dc8bde","receipt_sha256":"81555835110bf2c08677ca01e769e07c8c938a000be18c96fc749d6919c78efa","repair":"wiki-repair-20261023"},"short_desc":"Reports whether data checksums are enabled for this cluster.","short_desc_zh":"","source_rev":"wiki-repair-20261023:f2fb504b697d85ddf38a9a84c0b36e5d016da826ea21b0debbcd21f9df0ef4c7","unit":"","vartype":"enum"}},"Definition":{"Collection":"guc","Key":"data_checksums","SourceDatabase":"center","Version":"18","SourceTable":"guc","SourceKey":"data_checksums","SourceRevision":"wiki-repair-20261023:f2fb504b697d85ddf38a9a84c0b36e5d016da826ea21b0debbcd21f9df0ef4c7","Facts":{"boot_val":"off","category":"Preset Options","context":"internal","description":"Reports whether data checksums are enabled for this cluster. See -k for more information.","description_zh":"报告对这个集簇是否启用了数据校验和。详见 -k。","description_zh_html":"\u003cp\u003e\n        报告对这个集簇是否启用了数据校验和。详见 \u003ca class=\"xref\" href=\"/zh/docs/18/app-initdb.html#APP-INITDB-DATA-CHECKSUMS\"\u003e\u003ccode class=\"option\"\u003e-k\u003c/code\u003e\u003c/a\u003e。\n       \u003c/p\u003e","doc":{"anchor":"GUC-DATA-CHECKSUMS","file":"runtime-config-preset.html","lang":"en","sha256":"4dbfec727b9cee838adefb8a766217748d91ab90190b452a58cec737459582ce","slug":"18"},"documented":true,"enumvals":null,"extra_desc":null,"lang":"en","max_val":null,"metadata_version":"18","min_val":null,"name":"data_checksums","short_desc":"Shows whether data checksums are turned on for this cluster.","source":"pg-settings-source-snapshot","translation_provenance":{"inputs":[{"kind":"current-pgdoc-translation","path":"/Users/vonng/pgsty/pgdoc/zh/18/html/runtime-config-preset.html","sha256":"d0e95b9a81d5fdf853df26eba7dc096d96b9b45dadda13e0d0353aa72ac7a7b9"}],"kind":"same-version-pgdoc","locale":"zh-Hans","source_revision":"b1b500221dbe5437cfca004d6b04d3f6e422765d","version":"18"},"unit":null,"vartype":"bool","zh_from":"same-version-pgdoc"},"ManualEvidence":{"doc":{"anchor":"GUC-DATA-CHECKSUMS","file":"runtime-config-preset.html","lang":"en","sha256":"4dbfec727b9cee838adefb8a766217748d91ab90190b452a58cec737459582ce","slug":"18"}},"MeasuredEvidence":{"metadata_version":"18"}},"Text":{"Collection":"guc","Key":"data_checksums","SourceDatabase":"center","Version":"18","Locale":"en","Title":"data_checksums","Summary":"Reports whether data checksums are enabled for this cluster. See -k for more information.","BodyHTML":"\u003cp\u003eReports whether data checksums are enabled for this cluster. See -k for more information.\u003c/p\u003e","SourceRevision":"wiki-repair-20261023:f2fb504b697d85ddf38a9a84c0b36e5d016da826ea21b0debbcd21f9df0ef4c7","ContentHash":"03531f65cc02be8aeda9113de79840828a6a20a7a776591a82287915f99f8b76","Payload":{"description":"Reports whether data checksums are enabled for this cluster. See -k for more information."}},"RequestedLocale":"en","Fallback":false,"Versions":["10","11","12","13","14","15","16","17","18","19","20","9.3","9.4","9.5","9.6"],"Locales":["en","zh-Hans"],"Signatures":null,"Spellings":null,"SQLState":null,"Evidence":null}