Re: Degrading PostgreSQL 8.4 write performance - Mailing list pgsql-performance

From Pierre C
Subject Re: Degrading PostgreSQL 8.4 write performance
Date
Msg-id op.vxcifizfeorkce@apollo13
Whole thread Raw
In response to Degrading PostgreSQL 8.4 write performance  (Kabu Taah <kabuutah@hot.ee>)
List pgsql-performance
>                 Load testing of postgresql 8.4 for OLTP application
> suitability showed that throughput of the
> database significantly degraded over time from thousands of write
> transactions per second to almost zero.

A typical postgres benchmarking gotcha is :

- you start with empty tables
- the benchmark fills them
- query plans which were prepared based on stats of empty (or very small)
tables become totally obsolete when the table sizes grow
- therefore everything becomes very slow as the tables grow

So you should disconnect/reconnect or issue a DISCARD ALL periodically on
each connection, and of course periodically do some VACUUM ANALYZE (or
have autovacuum do that for you).

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