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How does vacuum full work in PostgreSQL 10?
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 exclusive lock on each table while it is being processed. When the option list is surrounded by parentheses, the options can be written in any order.
When was parenthesized added to Postgresql 9.0?
The parenthesized syntax was added in PostgreSQL 9.0; the unparenthesized syntax is deprecated. Selects “full” vacuum, which can reclaim more space, but takes much longer and exclusively locks the table.
Can a superuser vacuum all tables in a database?
However, database owners are allowed to vacuum all tables in their databases, except shared catalogs. (The restriction for shared catalogs means that a true database-wide VACUUM can only be performed by a superuser.) VACUUM will skip over any tables that the calling user does not have permission to vacuum.
When do you need to vacuum a table?
Therefore it’s necessary to do VACUUM periodically, especially on frequently-updated tables. With no parameter, VACUUM processes every table in the current database that the current user has permission to vacuum.
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.
Do you need disk space for vacuumdb full?
If you have the disk space to do a dump and restore, you should have the disk space to do a vacuumdb –full. The problem is that vacuumdb –full will make a copy of the entire data file. So, what you could do is:
The parenthesized syntax was added in PostgreSQL 9.0; the unparenthesized syntax is deprecated. Selects “full” vacuum, which can reclaim more space, but takes much longer and exclusively locks the table.
How big does vacuum full need to be?
As Stéphane mentions in the comments, this needs to be at least twice as big as the table in question as VACUUM FULL does a full copy. If you are lucky and can dynamically add a disk to the machine, do that. In the worst case you can just attach an USB disk (risky and slow though)! Next, mount the new device and make it available as tablespace:
What’s the difference between aggressive and aggressive freeze in vacuum?
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.
Is it possible to run vacuum full in PG?
Shrinking and growing tables is a heavyweight operation that’s best avoided if you’re just going to re-use the space. Pg doesn’t provide a VACUUM FULL CONCURRENTLY.
Do you need to reindex after a vacuum full In Postgres?
I read at several places that for Postgres > 9.0, I don’t need reindex after vacuum full, but I want to be sure that it is the case. A REINDEX immediately after a VACUUM FULL is useless because VACUUM FULL itself rebuilds the indexes. This is mentioned in the 9.4 documentation in Recovering Disk Space :
When to use autovacuum daemon in PostgreSQL?
The autovacuum daemon, if enabled, will automatically issue ANALYZE commands whenever the content of a table has changed sufficiently. However, administrators might prefer to rely on manually-scheduled ANALYZE operations, particularly if it is known that update activity on a table will not affect the statistics of “interesting” columns.
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