On Wed, Sep 10, 2014 at 2:25 PM, Heikki Linnakangas <hlinnakan...@vmware.com> wrote: > The dense-alloc-v5.patch looks good to me. I have committed that with minor > cleanup (more comments below). I have not looked at the second patch.
Gah. I was in the middle of doing this. Sigh. >> * the chunks size is 32kB (instead of 16kB), and we're using 1/4 >> threshold for 'oversized' items >> >> We need the threshold to be >=8kB, to trigger the special case >> within AllocSet. The 1/4 rule is consistent with ALLOC_CHUNK_FRACTION. > > Should we care about the fact that if there are only a few tuples, we will > nevertheless waste 32kB of memory for the chunk? I guess not, but I thought > I'd mention it. The smallest allowed value for work_mem is 64kB. I think we should change the threshold here to 1/8th. The worst case memory wastage as-is ~32k/5 > 6k. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
