35 lines
1.3 KiB
Plaintext
35 lines
1.3 KiB
Plaintext
.\" This is -*-nroff-*-
|
|
.\" XXX standard disclaimer belongs here....
|
|
.\" $Header: /cvsroot/pgsql/doc/man/Attic/vacuum.l,v 1.1.1.1 1996/08/18 22:14:28 scrappy Exp $
|
|
.TH VACUUM SQL 11/05/95 Postgres95 Postgres95
|
|
.SH NAME
|
|
vacuum \(em vacuum a database
|
|
.SH SYNOPSIS
|
|
.nf
|
|
\fBvacuum\fP
|
|
.fi
|
|
.SH DESCRIPTION
|
|
.BR Vacuum
|
|
is the Postgres vacuum cleaner. It opens every class in the database,
|
|
moves deleted records to the archive for archived relations, cleans
|
|
out records from aborted transactions, and updates statistics in the
|
|
system catalogs. The statistics maintained include the number of
|
|
tuples and number of pages stored in all classes. Running
|
|
.BR vacuum
|
|
periodically will increase Postgres's speed in processing user queries.
|
|
.PP
|
|
The open database is the one that is vacuumed.
|
|
.PP
|
|
We recommend that production databases be vacuumed nightly, in order
|
|
to keep statistics relatively current. The
|
|
.BR vacuum
|
|
query may be executed at any time, however. In particular, after
|
|
copying a large class into Postgres or deleting a large number of
|
|
records, it may be a good idea to issue a
|
|
.BR vacuum
|
|
query. This will update the system catalogs with the results of all
|
|
recent changes, and allow the Postgres query optimizer to make better
|
|
choices in planning user queries.
|
|
.SH "SEE ALSO"
|
|
vacuum(1).
|