"Inaam Rana" <[EMAIL PROTECTED]> wrote: > Did you had a chance to look into this any further? We, at EnterpriseDB, > have done some testing on this patch (dbt2 runs) and it looks like we are > getting the desired results, particularly so when we spread out both sync > and write phases.
Thank you for testing! Yes, I'm cleaning the patch. I changed configuration parameters to delay each phase in checkpoints from setting absolute times (checkpoint_xxx_duration) to setting relative to checkpoint_timeout (checkpoint_xxx_percent). Delay factors strongly depend on total checkpoint lengths, so I think the relative method is better. I tested the patch on my machine, too. The belows are the results of pgbench with/without the patch. As you see, the patch is not a complete solution -- 12s of response time is not satisfiable yet -- but it was better than other possible settings we could choose now. pgbench -s100 -c16 -t100000 on the machine with 1GB ram and one SCSI drive | A | B | C | D | --------------------------+--------+--------+--------+--------+ bgwriter_all_maxpages | 5 | 5 | 60 | 120 | checkpoint_write_percent | 50.0 | 0 | 0 | 0 | checkpoint_nap_percent | 10.0 | 0 | 0 | 0 | checkpoint_sync_percent | 20.0 | 0 | 0 | 0 | --------------------------+--------+--------+--------+--------+ pgbench tps | 612.23 | 517.64 | 488.90 | 378.39 | response average | 2.50ms | 2.89ms | 3.12ms | 3.99ms | response maximum | 12.23s |123.66s | 55.09s | 36.72s | --------------------------+--------+--------+--------+--------+ A: Proposed configurations with patch B: Default configurations C: Make bgwriter aggressive D: Make bgwriter more aggressive Other configurations: - full_page_writes = off - wal_buffers = 4MB - checkpoint_segments = 32 - checkpoint_timeout = 15min Regards, --- ITAGAKI Takahiro NTT Open Source Software Center ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match