On Sunday, March 03, 2013 8:19 PM Craig Ringer wrote: > On 02/05/2013 11:53 PM, Amit Kapila wrote: > >> Performance data for the patch is attached with this mail. > >> Conclusions from the readings (these are same as my previous patch): > >> > >> 1. With orignal pgbench there is a max 7% WAL reduction with not > much > >> performance difference. > >> 2. With 250 record pgbench there is a max wal reduction of 35% with > not > >> much performance difference. > >> 3. With 500 and above record size in pgbench there is an improvement > in > >> the performance and wal reduction both. > >> > >> If the record size increases there is a gain in performance and wal > >> size is reduced as well. > >> > >> Performance data for synchronous_commit = on is under progress, I > shall > >> post it once it is done. > >> I am expecting it to be same as previous. > > Please find the performance readings for synchronous_commit = on. > > > > Each run is taken for 20 min. > > > > Conclusions from the readings with synchronous commit on mode: > > > > 1. With orignal pgbench there is a max 2% WAL reduction with not much > > performance difference. > > 2. With 500 record pgbench there is a max wal reduction of 3% with > not much > > performance difference. > > 3. With 1800 record size in pgbench there is both an improvement in > the > > performance (approx 3%) as well as wal reduction (44%). > > > > If the record size increases there is a very good reduction in WAL > size. > > The stats look fairly sane. I'm a little concerned about the apparent > trend of falling TPS in the patched vs original tests for the 1-client > test as record size increases, but it's only 0.0%->0.2%->0.4%, and the > 0.4% case made other config changes too. Nonetheless, it might be wise > to check with really big records and see if the trend continues.
For bigger size (~2000) records, it goes into toast, for which we don't do this optimization. This optimization is mainly for medium size records. With Regards, Amit Kapila. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
