Re: [HACKERS] Disk usage for intermediate results in join
On Tue, Mar 11, 2014 at 1:24 PM, Parul Lakkad wrote: > I am trying to figure out when disk is used to store intermediate results > while performing joins in postgres. Joins can also cause a Nested Loop+Materialize plan, which spills to disk if the materialize result set is too large for work_mem. Regards, Marti -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Disk usage for intermediate results in join
On 03/11/2014 01:24 PM, Parul Lakkad wrote: Hi, I am trying to figure out when disk is used to store intermediate results while performing joins in postgres. According my findings using 'explain analyse ' only merge sort uses disk. Can anyone please throw some more light on this? Hash joins will also spill to disk if the hash-side of the join is large enough. The planner usually tries to avoid it, but sometimes it happens. - Heikki -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers