VACUUM(7)

📦 version 17.11, in opensuse-leap 16.0

💅 VACUUM(7) — the PostgreSQL 17.11 documentation glow-up, part 1 ✨

Okay bestie, welcome to VACUUM(7) — yes, that's the PostgreSQL 17.11 documentation, and no, we are not skipping a single line. This is the whole thing, rewritten with the energy it deserves. Buckle up. 🎀

🌸 NAME 🌸

VACUUM — garbage-collect and optionally analyze a database. That's the whole vibe: clean up the mess and, if you want, take a little look at the data while you're at it. 🧹✨

🦋 SYNOPSIS 🦋

VACUUM [ ( option [, ...] ) ] [ 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_MAIN [ boolean ]
    PROCESS_TOAST [ boolean ]
    TRUNCATE [ boolean ]
    PARALLEL integer
    SKIP_DATABASE_STATS [ boolean ]
    ONLY_DATABASE_STATS [ boolean ]
    BUFFER_USAGE_LIMIT size

and table_and_columns is:

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

That's the whole shape of it. Options go in parentheses, then table-and-columns, and there are a lot of options — but we'll get to those later. This part is the concept check, and it's giving "lecture but make it cute." 💖

💜 DESCRIPTION 💜

Okay so here's the tea: VACUUM reclaims storage occupied by dead tuples. In normal PostgreSQL operation, tuples that are deleted or obsoleted by an update are not physically removed from their table — they literally just sit there, haunting the place, until a VACUUM is done. That's why you have to run VACUUM periodically, especially on tables that get updated a lot. No cap, those are the ones that need it most. 👑🧹

Without a table_and_columns list, VACUUM processes every table and materialized view in the current database that the current user has permission to vacuum. With a list, it processes only those table(s). Simple as that, bestie. 🫶

VACUUM ANALYZE performs a VACUUM and then an ANALYZE for each selected table. It's a handy combination form for routine maintenance scripts — like a two-for-one situation, and honestly? Obsessed. See ANALYZE(7) for more details about its processing. 💅

Plain VACUUM (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, since an exclusive lock is not obtained. Iconic behavior, truly. However, extra space is not returned to the operating system (in most cases); 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. Zero. None. Bye. 💀

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. Sounds slay, right? But it is much slower and requires an ACCESS EXCLUSIVE lock on each table while it is being processed. So like… plan accordingly, bestie, because that lock is not here to make friends. 😭🔒

Part 1 is done, but we are not done — more parts are coming, so don't go anywhere. 🌸✨

✨ PARAMETERS ✨

  • FULL — okay so this picks the “full” vacuum, which can reclaim more space, but it takes much longer and exclusively locks the table. It also needs extra disk space, because it writes a new copy of the table and doesn’t release the old copy until the operation is complete. Usually you only want this when a significant amount of space needs to be reclaimed from inside the table. 💅
  • FREEZE — selects aggressive “freezing” of tuples. Specifying FREEZE is equivalent to doing 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 — prints a detailed vacuum activity report for each table. Basically the group chat updates, but for your vacuum. 🫶
  • ANALYZE — updates the statistics used by the planner to determine the most efficient way to execute a query. Planner glow-up, no cap. 📊
  • DISABLE_PAGE_SKIPPING — normally, VACUUM skips 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 it’s intended to be used only when the contents of the visibility map are suspect, which should happen only if there is a hardware or software issue causing database corruption. 🚨
  • SKIP_LOCKED — says 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. 😭
  • INDEX_CLEANUP — normally, VACUUM skips 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 24.1.5). 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_MAIN — specifies that VACUUM should attempt to process the main relation. 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 a relation’s corresponding TOAST table. 🧚
  • PROCESS_TOAST — 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. 🍓
  • TRUNCATE — 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 ACCESS EXCLUSIVE lock on the table that the truncation requires. This option is ignored if the FULL option is used. 🎀
  • PARALLEL — 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 27.46). 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. ⚡
  • SKIP_DATABASE_STATS — specifies that VACUUM should skip updating the database-wide statistics about oldest unfrozen XIDs. Normally VACUUM will update these statistics once at the end of the command. However, this can take awhile in a database with a very large number of tables, and it will accomplish nothing unless the table that had contained the oldest unfrozen XID was among those vacuumed. Moreover, if multiple VACUUM commands are issued in parallel, only one of them can update the database-wide statistics at a time. Therefore, if an application intends to issue a series of many VACUUM commands, it can be helpful to set this option in all but the last such command; or set it in all the commands and separately issue VACUUM (ONLY_DATABASE_STATS) afterwards. 🌈
  • ONLY_DATABASE_STATS — specifies that VACUUM should do nothing except update the database-wide statistics about oldest unfrozen XIDs. When this option is specified, the table_and_columns list must be empty, and no other option may be enabled except VERBOSE. 👑
  • BUFFER_USAGE_LIMIT — specifies the Buffer Access Strategy ring buffer size for VACUUM. This size is used to calculate the number of shared buffers which will be reused as part of this strategy. 0 disables use of a Buffer Access Strategy. If ANALYZE is also specified, the BUFFER_USAGE_LIMIT value is used for both the vacuum and analyze stages. This option can’t be used with the FULL option except if ANALYZE is also specified. When this option is not specified, VACUUM uses the value from vacuum_buffer_usage_limit. Higher settings can allow VACUUM to run more quickly, but having too large a setting may cause too many other useful pages to be evicted from shared buffers. The minimum value is 128 kB and the maximum value is 16 GB. 🔥
  • boolean — 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. ✨
  • integer — specifies a non-negative integer value passed to the selected option. 🔢
  • size — specifies an amount of memory in kilobytes. Sizes may also be specified as a string containing the numerical size followed by any one of the following memory units: B (bytes), kB (kilobytes), MB (megabytes), GB (gigabytes), or TB (terabytes). 💾
  • table_name — 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 — 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 yes, bestie, you get the live commentary. 💖

💅 NOTES 💅

okay so before you go vacuuming everything in sight, there are a few lil' rules, bestie. listen up 💖

  • To vacuum a table, one must ordinarily have the MAINTAIN privilege on the table. but listen — database owners are allowed to vacuum all tables in their databases, except shared catalogs. and VACUUM will skip over any tables that the calling user does not have permission to vacuum. it's not gonna fight you about it, it just quietly moves on 🙈
  • While VACUUM is running, the search_path is temporarily changed to pg_catalog, pg_temp. just so you know ✨
  • VACUUM cannot be executed inside a transaction block. no cap, it just can't 🚫
  • 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 64.4.4.1 for details 👑
  • we highkey recommend that all databases be vacuumed regularly in order to remove dead rows. PostgreSQL includes an "autovacuum" facility which can automate routine vacuum maintenance — it's literally the main character that does the chores for you 🧚 for more information about automatic and manual vacuuming, see Section 24.1.
  • 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. it's giving deep-clean-your-room energy, not daily-tidy energy 🎀
  • the PARALLEL option is used only for vacuum purposes. if this option is specified with the ANALYZE option, it does not affect ANALYZE. so don't expect it to do anything extra there, fr fr 💀
  • 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 19.4.4 for details. think of it as everyone taking a lil' nap proportional to their shift 🌸
  • 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 27.4.5 and Section 27.4.2 for details. progress bar realness 📊✨

✨ EXAMPLES ✨

okay so the moment you've been waiting for — to clean a single table onek, analyze it for the optimizer and print a detailed vacuum activity report:

VACUUM (VERBOSE, ANALYZE) onek;

that's it. that's the whole vibe. go off 👑

🦋 COMPATIBILITY 🦋

bestie. there is no VACUUM statement in the SQL standard. it's a PostgreSQL original, iykyk 🫶

the following syntax was used before PostgreSQL version 9.0 and is still supported:

VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ table_and_columns [, ...] ]
⚠️ note that in this syntax, the options must be specified in exactly the order shown. do not freestyle it, bestie — the order is the whole point 🙈

🌈 SEE ALSO 🌈

  • vacuumdb(1)
  • Section 19.4.4
  • Section 24.1.6
  • Section 27.4.5
  • Section 27.4.2

and that's the whole page, bestie!! 💜 this lil' masterpiece is from PostgreSQL 17.11, dated 2026, and it's the VACUUM(7) page — go forth and vacuum responsibly, mwah 🎀✨🦋

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