Re: Query with order by and limit is very slow - wrong index used - Mailing list pgsql-performance

How many rows do you have in that table?

I think , that planner thinks that the element you are looking for is
so common - that it will be to expensive to use index to fetch it.
Perhaps try increasing default_statistics_target , and revacuuming the table.

You could also try changing it just for the column:

ALTER TABLE records ALTER id SET source_id 1000; vacuum analyze verbose records;