VACUUM(7)

πŸ“¦ version 15.19, in opensuse-leap 16.0

πŸ’… VACUUM β€” like, the manual page, bestie (VACUUM(7), PostgreSQL 15.19 Documentation)

okay so. this is the <pink>VACUUM</pink> page from the PostgreSQL 15.19 docs and honestly? she's a big one. grab a snack πŸ“


✨ NAME ✨

VACUUM β€” garbage-collect and optionally analyze a database πŸ—‘οΈβœ¨


🌸 SYNOPSIS 🌸

VACUUM [ ( option [, ...] ) ] [ table_and_columns [, ...] ]
VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ table_and_columns [, ...] ]

where option can be one of:

    FULL [ boolean ]
    FREEZE [ boolean ]
    VERBOSE [ boolean ]
    ANALYZE [ boolean ]
    DISABLE_PAGE_SKIPPING [ boolean ]
    SKIP_LOCKED [ boolean ]
    INDEX_CLEANUP { AUTO | ON | OFF }
    PROCESS_TOAST [ boolean ]
    TRUNCATE [ boolean ]
    PARALLEL integer

and table_and_columns is:

    table_name [ ( column_name [, ...] ) ]

copy that exactly, no cap 🫢


πŸ¦‹ DESCRIPTION πŸ¦‹

so VACUUM reclaims storage occupied by dead tuples. and in normal PostgreSQL operation, tuples that get deleted or obsoleted by an update are not physically removed from their table β€” they just sit there, haunting the place πŸ‘» β€” and they remain present until a VACUUM is done. so that's why you gotta do VACUUM periodically, especially on tables that get updated a lot. she's maintenance, she's self-care, she's necessary πŸ’…

if you don't give a table_and_columns list, VACUUM processes every table and materialized view in the current database that the current user has permission to vacuum. give it a list and VACUUM processes only those table(s). simple as that ✨

VACUUM ANALYZE performs a VACUUM and then an ANALYZE for each selected table. it's giving handy combination form for routine maintenance scripts, honestly. see ANALYZE(7) for more details about its processing πŸ‘‘

plain VACUUM (so, without FULL) simply reclaims space and makes it available for re-use. this form of the command can operate in parallel with normal reading and writing of the table, because an exclusive lock is not obtained. however, extra space is not returned to the operating system (in most cases) β€” it's just kept available for re-use within the same table. it also allows us to leverage multiple CPUs in order to process indexes. this feature is known as parallel vacuum. to disable this feature, one can use the PARALLEL option and specify parallel workers as zero.

VACUUM FULL rewrites the entire contents of the table into a new disk file with no extra space, allowing unused space to be returned to the operating system. this form is much slower 😭 and requires an ACCESS EXCLUSIVE lock on each table while it is being processed.

ok bestie listen β€” when the option list is surrounded by parentheses, the options can be written in any order. without parentheses, options must be specified in exactly the order shown above. the parenthesized syntax was added in PostgreSQL 9.0; the unparenthesized syntax is deprecated πŸ’€

πŸŽ€ PARAMETERS πŸŽ€

  • FULL β€” selects β€œfull” vacuum, which can reclaim more space, but takes much longer and exclusively locks the table. this method also requires extra disk space, since it writes a new copy of the table and doesn't release the old copy until the operation is complete. usually this should only be used when a significant amount of space needs to be reclaimed from within the table πŸ™ˆ
  • FREEZE β€” selects aggressive β€œfreezing” of tuples. specifying FREEZE is equivalent to performing VACUUM with the vacuum_freeze_min_age and vacuum_freeze_table_age parameters set to zero. aggressive freezing is always performed when the table is rewritten, so this option is redundant when FULL is specified 🧊
  • VERBOSE β€” prints a detailed vacuum activity report for each table. she's chatty and we love her πŸ’¬
  • ANALYZE β€” updates statistics used by the planner to determine the most efficient way to execute a query πŸ“Š
  • DISABLE_PAGE_SKIPPING β€” normally, VACUUM will skip pages based on the visibility map. pages where all tuples are known to be frozen can always be skipped, and those where all tuples are known to be visible to all transactions may be skipped except when performing an aggressive vacuum. furthermore, except when performing an aggressive vacuum, some pages may be skipped in order to avoid waiting for other sessions to finish using them. this option disables all page-skipping behavior, and is intended to be used only when the contents of the visibility map are suspect β€” which should happen only if there is a hardware or software issue causing database corruption 😭
fr fr, that last one is a "something is deeply wrong" option, not a "let's try it and see" option 🚨
  • SKIP_LOCKED β€” specifies that VACUUM should not wait for any conflicting locks to be released when beginning work on a relation: if a relation cannot be locked immediately without waiting, the relation is skipped. note that even with this option, VACUUM may still block when opening the relation's indexes. additionally, VACUUM ANALYZE may still block when acquiring sample rows from partitions, table inheritance children, and some types of foreign tables. also, while VACUUM ordinarily processes all partitions of specified partitioned tables, this option will cause VACUUM to skip all partitions if there is a conflicting lock on the partitioned table πŸ”’
  • INDEX_CLEANUP β€” normally, VACUUM will skip index vacuuming when there are very few dead tuples in the table. the cost of processing all of the table's indexes is expected to greatly exceed the benefit of removing dead index tuples when this happens. this option can be used to force VACUUM to process indexes when there are more than zero dead tuples. the default is AUTO, which allows VACUUM to skip index vacuuming when appropriate. if INDEX_CLEANUP is set to ON, VACUUM will conservatively remove all dead tuples from indexes. this may be useful for backwards compatibility with earlier releases of PostgreSQL where this was the standard behavior.

INDEX_CLEANUP can also be set to OFF to force VACUUM to always skip index vacuuming, even when there are many dead tuples in the table. this may be useful when it is necessary to make VACUUM run as quickly as possible to avoid imminent transaction ID wraparound (see Section 25.1.5). however, the wraparound failsafe mechanism controlled by vacuum_failsafe_age will generally trigger automatically to avoid transaction ID wraparound failure, and should be preferred. if index cleanup is not performed regularly, performance may suffer, because as the table is modified indexes will accumulate dead tuples and the table itself will accumulate dead line pointers that cannot be removed until index cleanup is completed 😬

this option has no effect for tables that have no index and is ignored if the FULL option is used. it also has no effect on the transaction ID wraparound failsafe mechanism. when triggered it will skip index vacuuming, even when INDEX_CLEANUP is set to ON.

  • PROCESS_TOAST β€” specifies that VACUUM should attempt to process the corresponding TOAST table for each relation, if one exists. this is usually the desired behavior and is the default. setting this option to false may be useful when it is only necessary to vacuum the main relation. this option is required when the FULL option is used 🍞 (toast!! get it)
  • TRUNCATE β€” specifies that VACUUM should attempt to truncate off any empty pages at the end of the table and allow the disk space for the truncated pages to be returned to the operating system. this is normally the desired behavior and is the default unless the vacuum_truncate option has been set to false for the table to be vacuumed. setting this option to false may be useful to avoid the ACCESS EXCLUSIVE lock on the table that the truncation requires. this option is ignored if the FULL option is used βœ‚οΈ
  • PARALLEL β€” perform index vacuum and index cleanup phases of VACUUM in parallel using integer background workers (for the details of each vacuum phase, please refer to Table 28.41). the number of workers used to perform the operation is equal to the number of indexes on the relation that support parallel vacuum, which is limited by the number of workers specified with the PARALLEL option if any, which is further limited by max_parallel_maintenance_workers. an index can participate in parallel vacuum if and only if the size of the index is more than min_parallel_index_scan_size. please note that it is not guaranteed that the number of parallel workers specified in integer will be used during execution. it is possible for a vacuum to run with fewer workers than specified, or even with no workers at all. only one worker can be used per index. so parallel workers are launched only when there are at least 2 indexes in the table. workers for vacuum are launched before the start of each phase and exit at the end of the phase. these behaviors might change in a future release. this option can't be used with the FULL option πŸ‘‘
  • boolean β€” specifies whether the selected option should be turned on or off. you can write TRUE, ON, or 1 to enable the option, and FALSE, OFF, or 0 to disable it. the boolean value can also be omitted, in which case TRUE is assumed βœ…
  • integer β€” specifies a non-negative integer value passed to the selected option πŸ”’
  • table_name β€” the name (optionally schema-qualified) of a specific table or materialized view to vacuum. if the specified table is a partitioned table, all of its leaf partitions are vacuumed 🌿
  • column_name β€” the name of a specific column to analyze. defaults to all columns. if a column list is specified, ANALYZE must also be specified ⚠️

🫢 OUTPUTS 🫢

when VERBOSE is specified, VACUUM emits progress messages to indicate which table is currently being processed. various statistics about the tables are printed as well. so basically she narrates her whole life at you and honestly? iconic πŸ’–


okay so that's the first chunk β€” like, the whole vibe and every single option β€” and there's more page coming, so don't go anywhere bestie, we're not done 😭✨

πŸ’… NOTES πŸ’…

Okay so permission vibes first, bestie: to vacuum a table, you ordinarily gotta be the table's owner or a superuser. BUT database owners are allowed to vacuum all tables in their databases, except shared catalogs. And because shared catalogs are restricted, a true database-wide VACUUM can only be performed by a superuser. If the calling user doesn't have permission to vacuum a table, VACUUM will literally skip over it. No drama, it just moves on πŸ’….

🚫 Big no-no: VACUUM cannot be executed inside a transaction block. That's the rule, fr fr.

For tables with GIN indexes, VACUUM (in any form) also completes any pending index insertions, by moving pending index entries to the appropriate places in the main GIN index structure. See Section 70.4.1 for details. ✨

We recommend that all databases be vacuumed regularly in order to remove dead rows. PostgreSQL includes an β€œautovacuum” facility which can automate routine vacuum maintenance. For more information about automatic and manual vacuuming, see Section 25.1. 🫢

The FULL option is not recommended for routine use, but might be useful in special cases. An example is when you have deleted or updated most of the rows in a table and would like the table to physically shrink to occupy less disk space and allow faster table scans. VACUUM FULL will usually shrink the table more than a plain VACUUM would. πŸ‘‘

The PARALLEL option is used only for vacuum purposes. If this option is specified with the ANALYZE option, it does not affect ANALYZE. Noted, bestie.

VACUUM causes a substantial increase in I/O traffic, which might cause poor performance for other active sessions. Therefore, it is sometimes advisable to use the cost-based vacuum delay feature. For parallel vacuum, each worker sleeps in proportion to the work done by that worker. See Section 20.4.4 for details. πŸŒ€

Each backend running VACUUM without the FULL option will report its progress in the pg_stat_progress_vacuum view. Backends running VACUUM FULL will instead report their progress in the pg_stat_progress_cluster view. See Section 28.4.3 and Section 28.4.4 for details. πŸ“Š

✨ EXAMPLES ✨

To clean a single table onek, analyze it for the optimizer and print a detailed vacuum activity report:

VACUUM (VERBOSE, ANALYZE) onek;

πŸ¦‹ COMPATIBILITY πŸ¦‹

There is no VACUUM statement in the SQL standard. Cute, simple, not a standard thing πŸ’€.

🌈 SEE ALSO 🌈

  • vacuumdb(1)
  • Section 20.4.4
  • Section 25.1.6
  • Section 28.4.3
  • Section 28.4.4

And that's the page! This little manual moment is from PostgreSQL 15.19, dated 2026, and it's the VACUUM(7) page. Byeee πŸ’–

πŸ“¦ where this page comes from