On 2013-08-30 01:10:40 +0300, Ants Aasma wrote: > On Fri, Aug 30, 2013 at 12:33 AM, Andres Freund <and...@2ndquadrant.com> > wrote: > > FWIW, WAL is still the major bottleneck for INSERT heavy workloads. The > > per CPU overhead actually minimally increased (at least in my tests), it > > just scales noticeably better than before. > > Interesting. Do you have any insight what is behind the CPU overhead? > Maybe the solution is to make WAL insertion cheap enough to not > matter. That won't be easy, but neither are the alternatives.
Funnily by far the biggest thing I have seen in benchmarks is the CRC32 computation. I plan to brush up my ~3 year old CRC32 reimplementation patch sometime, but afair you had a much better one? I have some doubts about weakening the hash function by also using FNV or similar here, so I'd first like to try how much of a difference a better CRC32 implementation can make with the current XLogInsert() implementation. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
