2016-07-27 11:06 GMT+02:00 Michael Paquier <michael.paqu...@gmail.com>:
> On Wed, Jul 27, 2016 at 5:54 PM, thomas veymont > <thomas.veym...@gmail.com> wrote: > > We switched from PostgreSQL server 9.3 to 9.5. From the very beginning > there > > was a noticeable drop in performances (for example : when injecting our > SQL > > dumps into 9.5, COPY and CREATE INDEX were very slow). > > > > Our configuration file was the same for 9.3 and 9.5, except for the > > "chekpoint segment" that has been deprecated. > > Which value are you using for max_wal_size and min_wal_size? And which > value of checkpoint_segments did you use previously? This could > influence the checkpoint frequency. > -- > Michael > in 9.3 we had : checkpoint_segments = 128 #checkpoint_timeout = 5min # range 30s-1h checkpoint_completion_target = 0.9 # checkpoint target duration, 0.0 - 1.0 #checkpoint_warning = 30s # 0 disables as far as I remember these settings were for faster bulk loading. in 9.5 we set: max_wal_size = 6GB # https://www.postgresql.org/docs/9.5/static/release-9-5.html, max_wal_size = (3 * checkpoint_segments) * 16MB #min_wal_size = 80MB though I tried max_wal_size = 3GB (default is 1GB) and did not notice any improvment. cheers tom
