{"Entry":{"collection":"guc","key":"log_rotation_size","name":"log_rotation_size","aliases":[],"metadata":{"baseline":false,"boot_human":"Not specified","boot_val":null,"category":"Reporting and Logging / Where to Log","category_zh":"","changed_in":["15","18"],"changes":[{"documentation_changed":false,"fields":{},"from":"7.4","status":"added","to":"8.0"},{"documentation_changed":true,"fields":{},"from":"8.0","status":"changed","to":"8.1"},{"documentation_changed":true,"fields":{},"from":"8.1","status":"changed","to":"8.2"},{"documentation_changed":true,"fields":{},"from":"8.2","status":"changed","to":"8.3"},{"documentation_changed":true,"fields":{},"from":"11","status":"changed","to":"12"},{"documentation_changed":false,"fields":{"short_desc":{"from":"Automatic log file rotation will occur after N kilobytes.","to":"Sets the maximum size a log file can reach before being rotated."}},"from":"14","status":"changed","to":"15"},{"documentation_changed":false,"fields":{"extra_desc":{"from":null,"to":"0 disables size-based creation of new log files."},"max_val":{"from":"2097151","to":"2147483647"}},"from":"17","status":"changed","to":"18"}],"content_hash":"fe720803cd438a4edb46d5f6d2e1e7c7a71741fe54e7d4f6ec8793ad9cbdd080","context":"","default_changed_in":[],"default_history":[{"from":"9.0","to":"19","value":"10 MiB"}],"derived_content_hash":"28c1cbdf463e621b2d33000323b313ecdbd8c23d75f69f8d6bcdfe6cb025a76b","documentation_refresh":{"batch":"20261113","original_source_rev":"wiki-repair-20261023:df05c85ba73c72b62dadab506c44641cdc6c2e1ff498afbb65597bbce6b3fa89","versions":{"14":"14.25","15":"15.20","16":"16.16","17":"17.12","18":"18.7","19":"19rc2"}},"editorial":{"advice":{"olap":"Analytical bursts can cross a size threshold repeatedly; test the resulting filename suffixes, shipping throughput, and maximum single-file size rather than choosing a larger number by habit.","oltp":"Use a nonzero log_rotation_size when file size itself must be bounded, and coordinate it with a filename that cannot collide during multiple rotations in one time period. If set to zero, verify that time-based rotation and disk alerts provide the bound instead.","small":"A modest size cap limits damage from a logging spike, but too-small files increase metadata and shipping overhead. Zero is acceptable only with a proven time-based cycle and free-space guardrail."},"mechanism":["log_rotation_size sets the maximum size a log file can reach before being rotated. 0 disables size-based creation of new log files. The collector rotates when the current file reaches approximately this size; zero disables the size trigger but not time-based rotation.","log_rotation_size is a SIGHUP-context setting: a configuration reload activates the new server value without a restart; subsequent operations that consult it use the refreshed value.","The active path is composed from log_destination, logging_collector or syslog/eventlog, file naming and permissions, rotation triggers, and external shipping or retention."],"pitfalls":["Editing log_rotation_size without reloading configuration and verifying the effective value and subsequent behavior.","Combining incompatible destination, collector, filename, and rotation assumptions and then losing or overwriting logs.","Failing to monitor a full or unwritable log target, which can block logging or database activity depending on the path.","Setting zero without a working time-based or external rotation policy and allowing unbounded growth."],"references":[{"title":"PostgreSQL 19 Beta 4: log_rotation_size","url":"https://www.postgresql.org/docs/19/runtime-config-logging.html#GUC-LOG-ROTATION-SIZE"},{"title":"PostgreSQL 19 release notes","url":"https://www.postgresql.org/docs/19/release-19.html"}],"related":["logging_collector","log_destination","log_directory","log_filename","log_rotation_age"],"summary":"log_rotation_size is the PostgreSQL setting that defines the maximum size a log file can reach before being rotated."},"enumvals":[],"first_version":"8.0","group":"Reporting and Logging","group_slug":"logging","imported_at":"2026-09-30T00:40:57.414578+08:00","intro_commit":{},"key":"log_rotation_size","last_version":"20","max_val":"","min_val":"","name":"log_rotation_size","position":245,"present_in":["8.0","8.1","8.2","8.3","8.4","9.0","9.1","9.2","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:316dcb08f196ee077fd73884fc4194e506d3a56051a2a6738e092208e6ad253e","receipt_sha256":"af068777d5ee156ecfe764f90890b162fc360e3338816b0432ead456a9a1a770","repair":"wiki-repair-20261023"},"short_desc":"When logging_collector is enabled, this parameter determines the maximum size of an individual log file.","short_desc_zh":"","source_rev":"wiki-repair-20261023:df05c85ba73c72b62dadab506c44641cdc6c2e1ff498afbb65597bbce6b3fa89","unit":"","vartype":"integer"}},"Definition":{"Collection":"guc","Key":"log_rotation_size","SourceDatabase":"center","Version":"18","SourceTable":"guc","SourceKey":"log_rotation_size","SourceRevision":"wiki-repair-20261023:df05c85ba73c72b62dadab506c44641cdc6c2e1ff498afbb65597bbce6b3fa89","Facts":{"boot_val":"10240","category":"Reporting and Logging / Where to Log","context":"sighup","description":"When logging_collector is enabled, this parameter determines the maximum size of an individual log file. 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After this amount of data has been emitted into a log file, a new log file will be created. If this value is specified without units, it is taken as kilobytes. The default is 10 megabytes. Set to zero to disable size-based creation of new log files. 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