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> > I don't know that tcp-b does > > tpcb.jar is a java implementation of the http://www.tpc.org/tpcb/ > benchmark. It is not particularly representative of my workload, but > gives a synthetic, db-agnostic, view of the system performance. > We use it to have quick view to compare differents servers (different > OS, different RDBMS, etc...).
For information, pgbench is a sort of limited TPC-B benchmark.
> That said, the test wil create tables, load them with data, and perform > some transactions on them. > The point that makes me wonder what happens, is that the test run on my > main database is slow, while the same test run on a database on its own > is quick.
Do you mean when you run it against already existing data vs its own TPC-B DB?
> This is the same postgresql cluster (same postgresql.conf), same > tablespace (so same disks), same hardware obviously. > > Regarding the server activity, it seems quite flat : iostat shows that > disks are not working much (less than 5%), top shows only one active > core, and load average is well under 1... > > > http://wiki.postgresql.org/wiki/Show_database_bloat > > How do I interpret the output of this query ? Is 1.1 bloat level on a > table alarming, or quite ok ?
quite ok. The threshold for maintenance task is around 20%. I wonder about your system catalogs (pg_type, pg_attribute, ...)
You can use low level tool provided by PostgreSQL to help figure what's going wrong. pg_buffercache, pg_stattuple come first to explore your cached data and the block content.
Or some weird database configuration ? (parameters in PostgreSQL can be set per DB, per role, etc...) -- Cédric Villemain +33 (0)6 20 30 22 52 http://2ndQuadrant.fr/ PostgreSQL: Support 24x7 - Développement, Expertise et Formation |
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