| From: | Kenneth Marshall <ktm(at)rice(dot)edu> |
|---|---|
| To: | Don Seiler <don(at)seiler(dot)us> |
| Cc: | Joshua Drake <jd(at)commandprompt(dot)com>, pgsql-performance(at)lists(dot)postgresql(dot)org |
| Subject: | Re: High COMMIT times |
| Date: | 2021-01-06 19:15:25 |
| Message-ID: | 20210106191525.GH7881@aart.rice.edu |
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| Thread: | |
| Lists: | pgsql-performance |
On Wed, Jan 06, 2021 at 12:06:27PM -0600, Don Seiler wrote:
> On Wed, Jan 6, 2021 at 10:51 AM Joshua Drake <jd(at)commandprompt(dot)com> wrote:
>
> Looking at the Azure portal metric, we are nowhere close to the advertised
> maximum IOPS or MB/s throughput (under half of the maximum IOPS and under a
> quarter of the MB/s maximum). So there must be some other bottleneck in
> play. The IOPS limit on this VM size is even higher so that shouldn't be it.
>
Hi Don,
I may just be re-stating common knowledge, but the available IOPS would
be constrained by how tightly coupled the storage is to the CPU. Even a
small increase can limit the maximum IOPS unless you can issue multiple
relatively independent queries at one. I know no details of how Azure
implements their storage tiers.
Regards,
Ken
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