May 2018
Intermediate to advanced
576 pages
30h 25m
English
First, analyze your database using this code:
db_01=# analyse;ANALYZETime: 6231.313 msdb_01=#
This is the first thing to try, as it is usually cheap and is meant to be done quite often anyway.
If this restores the query's performance or at least improves the current performance considerably, then it means that autovacuum is not doing its task well, and the next thing to do is to find out why.
You must ensure that the performance improvement is not due to caching of the pages required by the requested query. Make sure that you repeat your query several times before classifying it as slow. Looking at pg_stat_statements (which is covered later in this chapter) can help you analyze the impact of a particular query in terms of caching, ...