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help / color / mirror / Atom feedFrom: Jim Nasby <[email protected]>
To: Shulgin, Oleksandr <[email protected]>
To: Pavel Stehule <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: On-demand running query plans using auto_explain and signals
Date: Mon, 28 Sep 2015 17:28:12 -0500
Message-ID: <[email protected]> (raw)
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On 9/18/15 5:05 AM, Shulgin, Oleksandr wrote:
>
> It should not be true - the data sender create DSM and fills it.
> Then set caller slot and send signal to caller. Caller can free DSM
> any time, because data sender send newer touch it.
>
>
> But the requester can timeout on waiting for reply and exit before it
> sees the reply DSM. Actually, I now don't even think a backend can free
> the DSM it has not created. First it will need to attach it,
> effectively increasing the refcount, and upon detach it will only
> decrease the refcount, but not actually release the segment...
>
> So this has to be the responsibility of the reply sending backend in the
> end: to create and release the DSM *at some point*.
What's wrong with just releasing it at the end of the statement? When
the statement is done there's no point to reading it asynchronously anymore.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
--
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Subject: Re: On-demand running query plans using auto_explain and signals
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