Re: [HACKERS] Installation procedure. - Mailing list pgsql-hackers

From J. Michael Roberts
Subject Re: [HACKERS] Installation procedure.
Date
Msg-id Pine.GSO.4.10.9908012350270.15220-100000@school.cs.indiana.edu
Whole thread Raw
In response to Re: [HACKERS] Installation procedure.  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: [HACKERS] Installation procedure.
List pgsql-hackers
> Actually, when we set the default MAXBACKENDS to 32 for 6.5, it was
> done specifically to ensure that the default shared mem block size would
> stay under a meg.  (The equivalent setting in 6.4 was 64 backends.)
> But I guess various data structures changed a little bit after that
> time, and we ended up on the wrong side of the breakpoint without
> thinking about it.

Oops.  :-)

> Should we cut the default MAXBACKENDS some more, or just try to
> document the issue better?

I've added a paragraph to the system requirements in INSTALL which
explains the situation.  Now to figure out how to get the changes to you
guys....  Is the procedure simply to diff it and email it to somebody, or
what?  Just because I've been lurking on this list for nearly a year now
doesn't mean I know what I'm doing.

As to whether MAXBACKENDS should be changed -- I have no idea what impact
that would actually have.  What *is* a backend, precisely?  In Illustra,
anyway, each active query starts a new process while it's working -- is
that a backend?  I've never seen more than about 5 on my own server (not
that I hang around monitoring all the time) so 16 seems capacious.





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