2015-04-15 10:46 GMT+02:00 Andreas Joseph Krogh <andr...@visena.com>:
> På onsdag 15. april 2015 kl. 04:34:31, skrev Venkata Balaji N < > nag1...@gmail.com>: > > > >> I'm planning to vacuum FULL a pg_largeobject relation (after vacuumlo'ing >> it). The relation is 300GB large so I'm concerned the operation will write >> full my pg_xlog directory which is on a 200GB (net) RAID1 SSD. >> >> Where does vacuum FULL rewrite to, does it use pg_xlog or some other >> directory? >> > > Which version of PostgreSQL is this ? > > If i got your question correctly, VACUUM FULL would rewrite the data to a > new data file associated with that particular relation (Table) in the > "$PGDATA/base" directory. This needs an extra disk space at the OS level > (this is not related to pg_xlog directory). > > As VACUUMING is a data change operation, "pg_xlog" will also have only the > WAL data (modifications) written at the time of VACUUMING. > > http://www.postgresql.org/docs/9.4/static/sql-vacuum.html > > > This is PG-9.3 > > So I understand that VACUUM FULL writes the new table to the same > tablespace as the original table (also for system-catalogs like > pg_largeobject), and doesn't use any temp-space outside the location of > that tablespace? > You're right. -- Guillaume. http://blog.guillaume.lelarge.info http://www.dalibo.com
