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 (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers