I have a PostgreSQL 8.3.6, compiled by Visual C++ build 1400 running on Windows with virtual machine, 2 GB ram, and configured the postgresql.conf file to log statements duration >= 500 ms.
And I have this query/log entry: 2011-01-03 23:06:29 BRT LOG: duration: 2843.000 ms statement: SELECT DESCRICAO FROM CURSO WHERE CODCURSO = 2
My question is, this same query executes many times a day and many times fast/normal, but why in some cases its run slowly? Especialy because the "CODCURSO" column is PK and this table has only 3 registers (tiny table).