Re: [PATCH] 2PC state files on shared memory - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [PATCH] 2PC state files on shared memory
Date
Msg-id 3680.1249690291@sss.pgh.pa.us
Whole thread Raw
In response to [PATCH] 2PC state files on shared memory  (Michael Paquier <michael.paquier@gmail.com>)
Responses Re: [PATCH] 2PC state files on shared memory  (Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>)
List pgsql-hackers
Michael Paquier <michael.paquier@gmail.com> writes:
> Based on an idea of Heikki Linnakangas, here is a patch in order to improve
> 2PC
> by sending the state files of prepared transactions to shared memory instead
> of disk.

I don't understand how this can possibly work.  The entire point of
2PC is that the state file is guaranteed to be on disk so it will
survive a crash.  What good is it if it's in shared memory?

Quite aside from that, the fixed size of shared memory makes this seem
pretty impractical.
        regards, tom lane


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