Red Hat Bugzilla – Bug 50797
Write Ahead Log disk usage very large.
Last modified: 2007-04-18 12:35:27 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.3) Gecko/20010802
Description of problem:
Version 7.1.2 of postgres (the current version in roswell) can generate
many GB of Write ahead log (WAL) files for long transactions.
Steps to Reproduce:
1.Try restoring a pgdump that has a large table (few million rows) in it.
Actual Results: So many log files are generated that the disk partition
fills up and the restore of the database fails.
Expected Results: Shouldnt' use as much disk space.
A "zcat pgdump.gz | psql" of a 270 Mb pgdump.gz (~2Gb pgdump) generated
over 30Gb of WAL files in /var/lib/pgsql/data/pg_xlog.
There is a message on the postgresql mailing list relating to this, a patch
is available as well as further improvements on the CVS tip to resovle this
If a release of postgresql adds this, we'll have it. I don't want to add
restrictions for general use to handle a very specific case.
Believed to be fixed in postgresql-7.1.2-7, which contains various changes from
the 7.1-stable branch.
The packages are available for a limited time from http://people.redhat.com/teg/pg/