> We're still considering this architecture - so I don't have any plans. > > My question is, does the ANALYZE command, which is only executed on the > master, mean that the statistics / plans that are used on the master are > ALSO used on the slaves? OR .... does the slave create it's own plan? The statistics is same on master and slave. Plans are made on master and slave independently. > I would anticipate very different plans between the two machines, and > different postgresql.conf settings as well. > > I would *want* different query plans between the two. Is that possible? If you have different postgresql.conf settings on slave, you could get different plans on slave. Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp > On Sun, Nov 9, 2014 at 8:50 PM, Tatsuo Ishii <ishii@xxxxxxxxxxxxxx> wrote: > >> > Hi all! >> > >> > We're working on our architecture for our next set of systems, and we >> > normally have a simple master/slave with wal shipping and hot_standby set >> > up, with pgpool sitting in front of both to do load balancing. >> > >> > However, one piece I'm very confused about is the query plans on the >> slave >> > server. >> > >> > Let's pretend we have a master server with: >> > (2) E5-2660 CPU's >> > (4) S3700 400GB SSD's >> > 256GB of RAM >> > >> > And multiple slave servers that looks like: >> > (1) E3-1290 CPU's >> > (2) Intel 520 SSD's >> > 32GB of RAM >> > >> > There's a significant difference between the master and slaves. >> >> Can you show us the explain analyze result on both master and slave? >> >> > Does the ANALYZE command run on each system, and work differently on each >> > system, or would the slave servers use the query plans from the master >> > machine? >> >> ANALYZE can only be executed on master. Slave creates its own >> plan. However since statistics should be same as master, I guess if >> you get different plan, then postgresql.conf maybe different among >> master and slave. >> >> Best regards, >> -- >> Tatsuo Ishii >> SRA OSS, Inc. Japan >> English: http://www.sraoss.co.jp/index_en.php >> Japanese:http://www.sraoss.co.jp >> -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
