Effective IO Concurrency

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Effective IO Concurrency

luis.roberto
Hi!

In PostgreSQL 13, the way of using effective_io_concurrency has changed. Until v12, I used 200 for this value (using SSD drives). Using the new formula described in https://www.postgresql.org/docs/13/release-13.html gives me 1176. However, in the documentation https://www.postgresql.org/docs/13/runtime-config-resource.html#GUC-EFFECTIVE-IO-CONCURRENCY it says that the maximum value allowed is 1000.


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Re: Effective IO Concurrency

Laurenz Albe
On Mon, 2020-09-14 at 10:39 -0300, [hidden email] wrote:
> In PostgreSQL 13, the way of using effective_io_concurrency has changed. Until v12,
>  I used 200 for this value (using SSD drives). Using the new formula described in
> https://www.postgresql.org/docs/13/release-13.html gives me 1176.
>  However, in the documentation https://www.postgresql.org/docs/13/runtime-config-resource.html#GUC-EFFECTIVE-IO-CONCURRENCY
> it says that the maximum value allowed is 1000.

Then use the value 1000...

Yours,
Laurenz Albe
--
Cybertec | https://www.cybertec-postgresql.com



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Re: Effective IO Concurrency

Ron-2
On 9/14/20 11:03 AM, Laurenz Albe wrote:
> On Mon, 2020-09-14 at 10:39 -0300, [hidden email] wrote:
>> In PostgreSQL 13, the way of using effective_io_concurrency has changed. Until v12,
>>   I used 200 for this value (using SSD drives). Using the new formula described in
>> https://www.postgresql.org/docs/13/release-13.html gives me 1176.
>>   However, in the documentation https://www.postgresql.org/docs/13/runtime-config-resource.html#GUC-EFFECTIVE-IO-CONCURRENCY
>> it says that the maximum value allowed is 1000.
> Then use the value 1000...

I think he means that the formula should take that into account.

--
Angular momentum makes the world go 'round.


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Re: Effective IO Concurrency

luis.roberto
De: "Ron" <[hidden email]>
Para: "pgsql-general" <[hidden email]>
Enviadas: Segunda-feira, 14 de setembro de 2020 13:10:23
Assunto: Re: Effective IO Concurrency

On 9/14/20 11:03 AM, Laurenz Albe wrote:
> On Mon, 2020-09-14 at 10:39 -0300, [hidden email] wrote:
>> In PostgreSQL 13, the way of using effective_io_concurrency has changed. Until v12,
>>   I used 200 for this value (using SSD drives). Using the new formula described in
>> https://www.postgresql.org/docs/13/release-13.html gives me 1176.
>>   However, in the documentation https://www.postgresql.org/docs/13/runtime-config-resource.html#GUC-EFFECTIVE-IO-CONCURRENCY
>> it says that the maximum value allowed is 1000.
> Then use the value 1000...

I think he means that the formula should take that into account.

--
Angular momentum makes the world go 'round.

Exactly....

For future reference, and maybe a updated documentation:

SELECT least(round(sum(OLD / n::float)),1000) FROM generate_series(1, OLD) s(n)

I don't know how to write patches, so maybe someone can do that.

Thanks.