From: | Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com> |
---|---|
To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
Cc: | Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: optimizing vacuum truncation scans |
Date: | 2015-07-13 02:06:55 |
Message-ID: | CAJrrPGfusUbZf0Yg==tXQ0so55Y_4yXid=-MihrgYYykir4FNg@mail.gmail.com |
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Lists: | pgsql-hackers |
On Thu, Jul 9, 2015 at 5:36 PM, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com> wrote:
>
> I will do some performance tests and send you the results.
Here are the performance results tested on my machine.
Head vm patch vm+prefetch patch
First vacuum 120sec <1sec <1sec
second vacuum 180 sec 180 sec 30 sec
I did some modifications in the code to skip the vacuum truncation by
the first vacuum command.
This way I collected the second vacuum time taken performance.
I just combined your vm and prefetch patch into a single patch
vm+prefetch patch without a GUC.
I kept the prefetch as 32 and did the performance test. I chosen
prefetch based on the current
buffer access strategy, which is 32 for vacuum presently instead of an
user option.
Here I attached the modified patch with both vm+prefetch logic.
I will do some tests on a machine with SSD and let you know the
results. Based on these results,
we can decide whether we need a GUC or not? based on the impact of
prefetch on ssd machines.
Regards,
Hari Babu
Fujitsu Australia
Attachment | Content-Type | Size |
---|---|---|
vac_trunc_trust_vm_and_prefetch.patch | application/octet-stream | 4.0 KB |
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