On Thu, May 10, 2012 at 8:34 PM, MauMau <maumau307@xxxxxxxxx> wrote: > Today, they told me that they ran the test on two virtual machines on a > single physical machine. They also used pgpool-II in both cases. In > addition, they may have ran the applications and pgpool-II on the same > virtual machine as the database server. So they compared the throughput of one server running on a single machine (non replication case) with that of two servers (i.e., master and standby) running on the same single machine (sync rep case)? The amount of CPU/Mem/IO resource available per server is not the same between those two cases. So ISTM it's very unfair for sync rep case. In this situation, I'm not surprised if I see 50% performance degradation in sync rep case. > It sounded to me that the resource is so scarce that concurrency was low, or > your assumption may be correct. I'll hear more about their environment from > them. > > BTW it's pity that I cannot find any case study of performance of the > flagship feature of PostgreSQL 9.0/9.1, streaming replication... Though I cannot show the detail for some reasons, as far as I measured the performance overhead of sync rep by using pgbench, the overhead of throughput was less than 10%. When measuring sync rep, I used two set of physical machine and storage for the master and standby, and used 1Gbps network between them. Regards, -- Fujii Masao -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
