On 01/19/10 11:16, fkater@xxxxxxxxxxxxxx wrote:
fkater@xxxxxxxxxxxxxx:
I'll try to execute these tests on a SSD
and/or Raid system.
FYI:
On a sata raid-0 (mid range hardware) and recent 2x 1.5 TB
disks with a write performance of 100 MB/s (worst, to 200
MB/s max), I get a performance of 18.2 MB/s. Before, with
other disk 43 MB/s (worst to 70 MB/s max) postgres came to
14-16 MB/s.
[I just skimmed this thread - did you increase the number of WAL logs to
something very large, like 128?]
So, I conclude finally:
(1) Postgresql write throughput (slowly) scales with the
harddisk speed.
(2) The throughput (not counting WAL doubling data) in
postgresql is 20-25% of the disk thoughput.
And this is one of the more often forgot reasons why storing large
objects in a database rather than in the file systems is a bad idea :)
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