On 09/18/2014 03:09 PM, Mkrtchyan, Tigran wrote:
----- Original Message -----
From: "Josh Berkus" <josh@xxxxxxxxxxxx>
To: pgsql-performance@xxxxxxxxxxxxxx
Sent: Thursday, September 18, 2014 7:54:24 PM
Subject: Re: postgres 9.3 vs. 9.4
On 09/18/2014 08:09 AM, Mkrtchyan, Tigran wrote:
9.4beta2:
...
0.957854 END;
Looks like IO.
Postgres internal IO? May be. We get 600MB/s on this SSDs.
While it's possible that this is a Postgres issue, my first thought is
that the two SSDs are not actually identical. The 9.4 one may either
have a fault, or may be mostly full and heavily fragmented. Or the Dell
PCIe card may have an issue.
We have tested both SSDs and they have identical IO characteristics and
as I already mentioned, both databases are fresh, including filesystem.
You are using "scale 1" which is a < 1MB database, and one client and 1
thread, which is an interesting test I wouldn't necessarily have done
myself. I'll throw the same test on one of my machines and see how it does.
this scenario corresponds to our use case. We need a high transaction rate
per for a single client. Currently I can get only ~1500 tps. Unfortunately,
posgtress does not tell me where the bottleneck is. Is this is defensively
not the disk IO.
This is when you dig out tools like perf, maybe.
cheers
andrew
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