Vacuum
Cleans and analyzes a database.
Synopsis
VACUUM [ VERBOSE ] [ ANALYZE ] [ table ] VACUUM [ VERBOSE ] ANALYZE [ table [ (column [, ...] ) ] ]
Parameters
VERBOSE
The keyword that causes
VACUUM
to display an activity report for each table it operates upon.ANALYZE
The keyword that causes
VACUUM
to update column statistics for the optimizer.table
A table you intend to vacuum. If you do not specify a table,
VACUUM
will operate upon all tables.column
The name of a column to analyze (used when updating statistics for the optimizer).
Results
VACUUM
The message returned when a
VACUUM
successfully vacuums a database or table.NOTICE: âRelation tableâ
The notice returned when
VACUUM
begins cleaning a table (table
) while in verbose mode.NOTICE: Pages 1: Changed 1, reaped 1, Empty 0, New 0; Tup 12: Vac 39, Keep/VTL 0/0, Crash 0, UnUsed 0, MinLen 52, MaxLen 76; Re-using: Free/Avail. Space 7180/0; EndEmpty/Avail. Pages 0/0. CPU 0.00s/0.00u sec.
The notice returned from the analysis on a table.
NOTICE: Index
indexname
: Pages 2; Tuples 12: Deleted 39. CPU 0.00s/0.00u sec.
The notice returned from an analysis of
indexname
.
Description
Use the VACUUM
command to clean up records from rolled back
transactions and to update system catalog statistics. Call it with the ANALYZE
option to collect statistical information about data. Using this command
periodically can increase the performance of your database.
Example
The following example displays the output of the VACUUM
command when
run on the books
table with the ...
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