Re: Read consistency when using synchronous_commit=off - Mailing list pgsql-general

From pshadangi
Subject Re: Read consistency when using synchronous_commit=off
Date
Msg-id CAA+OQsQAQtN8Wk+PACjMxBz-5FzRSpcEp8MYb3Sx=R=qJsvNRg@mail.gmail.com
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In response to Re: Read consistency when using synchronous_commit=off  (Ravi Krishna <srkrishna@fastmail.com>)
Responses Re: Read consistency when using synchronous_commit=off  (Ravi Krishna <srkrishna@fastmail.com>)
List pgsql-general
> After better thinking, I have to reply to myself since I m not entirely sure of my previous question. (I m digging into the docs, but i do not want to mislead you in the meanwhile)
Yes, I was not able to get some statement regarding this in the docs, please let me know if you find something. Thanks.

> No.  On the standby the buffer cache has to be populated with the updates before other client sessions can read it.  AFAIK other client sessions do not read WAL buffers.
> That is why synchronous_commit=ON option is there.
We don't have standby instance, as I have mentioned we are using just one instance of postgres serving local clients running on the same machine, do you know in this case what is the behavior ?


On Tue, Jan 15, 2019 at 5:24 PM Ravi Krishna <srkrishna@fastmail.com> wrote:

> I m not sure other clients are able to read from WAL buffer, therefore i m not sure the data is
> available to other clients at that specific point in time.

No.  On the standby the buffer cache has to be populated with the updates before other client sessions can read it.  AFAIK other client sessions do not read WAL buffers.

That is why synchronous_commit=ON option is there.


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