On Monday, June 3, 2013, Amit Langote wrote:
Hello,
In what cases can a relation use more buffers (in shared memory) than
its pg_class.relpages?
I think relpages only counts pages in the main fork, while the buffer cache will also have buffers for the other forks (visibility map, free space map). Also, relpages can be out of date if the table has grown since the last vac/analyze.
Cheers,
Jeff