| From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
|---|---|
| To: | Moreno Andreo <moreno(dot)andreo(at)evolu-s(dot)it> |
| Cc: | PostgreSQL mailing lists <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: WAL directory size calculation |
| Date: | 2016-07-28 13:33:25 |
| Message-ID: | CAKFQuwaMGb-qMnf0T0F35NQg_FidzVugnBYhSz3AybMwkwppOg@mail.gmail.com |
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| Lists: | pgsql-general |
On Thu, Jul 28, 2016 at 9:25 AM, Moreno Andreo <moreno(dot)andreo(at)evolu-s(dot)it>
wrote:
> I've read somewhere that the formula should be 16 MB * 3 *
> checkpoint_segment in size.
>
[...]
> Using the above formula I have:
> 16 MB * 3 * 1 GB
> that leads to to ... uh .. 48000 TB?
>
You seem to be mis-remembering the formula.
checkpoiint_segments is a quantity (i.e., unit-less), not a size. Saying
its "1GB" makes no sense.
I'm also doubting you multiply it by 3 - add three to it maybe...
Each segment takes 16MB. The total space required is that times whatever
maximum count of segments you expect to have.
I'd suggest waiting for better responses on these lists or searching out
prior conversations on this topic - of which I am sure there are many.
David J.
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