Em 26/08/2014 09:16, "Fujii Masao" <masao.fu...@gmail.com> escreveu: > > On Tue, Aug 19, 2014 at 6:37 PM, Rahila Syed <rahilasye...@gmail.com> wrote: > > Hello, > > Thank you for comments. > > > >>Could you tell me where the patch for "single block in one run" is? > > Please find attached patch for single block compression in one run. > > Thanks! I ran the benchmark using pgbench and compared the results. > I'd like to share the results. > > [RESULT] > Amount of WAL generated during the benchmark. Unit is MB. > > Multiple Single > off 202.0 201.5 > on 6051.0 6053.0 > pglz 3543.0 3567.0 > lz4 3344.0 3485.0 > snappy 3354.0 3449.5 > > Latency average during the benchmark. Unit is ms. > > Multiple Single > off 19.1 19.0 > on 55.3 57.3 > pglz 45.0 45.9 > lz4 44.2 44.7 > snappy 43.4 43.3 > > These results show that FPW compression is really helpful for decreasing > the WAL volume and improving the performance. > > The compression ratio by lz4 or snappy is better than that by pglz. But > it's difficult to conclude which lz4 or snappy is best, according to these > results. > > ISTM that compression-of-multiple-pages-at-a-time approach can compress > WAL more than compression-of-single-... does. > > [HOW TO BENCHMARK] > Create pgbench database with scall factor 1000. > > Change the data type of the column "filler" on each pgbench table > from CHAR(n) to TEXT, and fill the data with the result of pgcrypto's > gen_random_uuid() in order to avoid empty column, e.g., > > alter table pgbench_accounts alter column filler type text using > gen_random_uuid()::text > > After creating the test database, run the pgbench as follows. The > number of transactions executed during benchmark is almost same > between each benchmark because -R option is used. > > pgbench -c 64 -j 64 -r -R 400 -T 900 -M prepared > > checkpoint_timeout is 5min, so it's expected that checkpoint was > executed at least two times during the benchmark. > > Regards, > > -- > Fujii Masao > > > -- > Sent via pgsql-hackers mailing list (firstname.lastname@example.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers
It'd be interesting to check avg cpu usage as well.