Re: Shared Memory: How to use SYSV rather than MMAP ? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Shared Memory: How to use SYSV rather than MMAP ?
Date
Msg-id 29496.1545842616@sss.pgh.pa.us
Whole thread Raw
In response to Re: Shared Memory: How to use SYSV rather than MMAP ?  (Thomas Munro <thomas.munro@enterprisedb.com>)
Responses Re: Shared Memory: How to use SYSV rather than MMAP ?
List pgsql-hackers
Thomas Munro <thomas.munro@enterprisedb.com> writes:
> Since it's not fixing a bug, we wouldn't back-patch that into existing
> releases.  But I agree that we should do something like this for
> PostgreSQL 12, and I think we should make it user configurable.

I'm -1 on making this user configurable via a GUC; that adds documentation
and compatibility burdens that we don't need, for something of no value
to 99.99% of users.  The fact that the default would need to be
platform-dependent just makes that tradeoff even worse.  I think the other
0.01% who need to change the default (and are bright enough to be doing
the right thing for the right reasons) could certainly handle something
like a pg_config_manual.h control symbol --- see USE_PPC_LWARX_MUTEX_HINT
for a precedent that I think applies well here.  So I'd favor just doing
it that way.

            regards, tom lane


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