Re: [HACKERS] Re: Max backend limits cleaned up

From: Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us>
To: daryl(at)www(dot)com (Daryl W(dot) Dunbar)
Cc: tgl(at)sss(dot)pgh(dot)pa(dot)us, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Re: Max backend limits cleaned up
Date: 1999-02-22 17:54:47
Message-ID: 199902221754.MAA04392@candle.pha.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

[Charset iso-8859-1 unsupported, filtering to ASCII...]
> The default to-date has been 64. The reason you don't see much
> trouble with it is twofold, 1) Linux has a huge default for
> semaphores and shared memory, 2) The old memory model allocated
> semaphores in blocks of 16 up to MaxBackedId (which was hard coded
> to 64). I did not run into trouble on untuned Solaris until
> postmaster tried to start the 49th backend (semaphores 49-64 when my
> kernel defaulted to 60).
>
> The new model allocates semaphores and shared memory at startup,
> assuring you won't experience midstream troubles like I did. It
> does, however allocate to the max or -N setting, which most users
> will probably never reach.
>
> I'd vote for 32 as the default.

I understand now. The stuff is preallocated.

--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 1999-02-22 21:28:48 Updated developers list
Previous Message Tom Lane 1999-02-22 17:51:17 Re: [HACKERS] Re: Max backend limits cleaned up