On Fri, Aug 30, 2013 at 12:43 PM, Peter Geoghegan <p...@heroku.com> wrote: > On Thu, Aug 29, 2013 at 7:55 PM, Fujii Masao <masao.fu...@gmail.com> wrote: >> [the amount of WAL generated during running pgbench] >> 4302 MB (compress_backup_block = off) >> 1521 MB (compress_backup_block = on) > > Interesting. > > I wonder, what is the impact on recovery time under the same > conditions?
Will test! I can imagine that the recovery time would be a bit longer with compress_backup_block=on because compressed FPW needs to be decompressed. > I suppose that the cost of the random I/O involved would > probably dominate just as with compress_backup_block = off. That said, > you've used an SSD here, so perhaps not. Oh, maybe my description was confusing. full_page_writes was enabled while running the benchmark even if compress_backup_block = off. I've not merged those two parameters yet. So even in compress_backup_block = off, random I/O would not be increased in recovery. Regards, -- Fujii Masao -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
