On 9.10.2012 00:33, Evgeny Shishkin wrote: >> >> pgbench: Old server >> >> pgbench -i -s 100 -U test >> pgbench -U test -c ... -t ... >> >> -c -t TPS >> 5 20000 3777 >> 10 10000 2622 >> 20 5000 3759 >> 30 3333 5712 >> 40 2500 5953 >> 50 2000 6141 >> >> New server >> -c -t TPS >> 5 20000 2733 >> 10 10000 2783 >> 20 5000 3241 >> 30 3333 2987 >> 40 2500 2739 >> 50 2000 2119 > > On new server postgresql do not scale at all. Looks like contention. Why? The evidence we've seen so far IMHO suggests a poorly performing I/O subsystem. Post a few lines of "vmstat 1" / "iostat -x -k 1" collected when the pgbench is running, that might tell us more. Try a few very basic I/O tests that are easy to understand rather than running bonnie++ which is quite complex. For example try this: time sh -c "dd if=/dev/zero of=myfile.tmp bs=8192 count=4194304 && sync" dd if=myfile.tmp of=/dev/null bs=8192 The former measures sequential write speed, the latter measures sequential read speed in a very primitive way. Watch vmstat/iostat and don't bother running pgbench until you get a reasonable performance on both systems. Tomas -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
