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Re: SR standby hangs

From: Greg Stark <gsstark(at)mit(dot)edu>
To: Andrew Dunstan <amdunstan(at)nc(dot)rr(dot)com>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: SR standby hangs
Date: 2011-02-20 17:39:18
Message-ID: AANLkTim+ysNv7SjzFZhOXJNmirGM3LYVj1jPYSwCcaSg@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Fri, Feb 18, 2011 at 6:59 PM, Andrew Dunstan <amdunstan(at)nc(dot)rr(dot)com> wrote:
> The server is running as a warm standby, and the client's application tries
> to connect to both the master and the slave, accepting whichever lets it
> connect (hence hot standby is not turned on).
>...
>   #2  0x00000000005de645 in LockBufferForCleanup () at bufmgr.c:2432
>   #3  0x0000000000463733 in heap_xlog_clean (lsn=<value optimized out>,

Hm, if hot standby isn't turned on why are we bothering with locks at
all? But that said is there *anything* else happening in the database
aside from recovery? Are there any errors in the database log?

But this still shouldn't block. It's either blocked locking the buffer
or blocked waiting for the buffer to become unpinned. It would be nice
to get a backtrace from a debugging build which wouldn't have some of
the functions inlined. It would be really nice to see the pin count on
the buffer in question -- perhaps it has gotten out of sync or
underflowed?

Hmm.... I wonder, does Tom's boot strapping hack to allow the
postmaster to use the real user and database tables cause pages in
those tables to become pinned? What happens if it plays a cleanup
recovery record on one of those tables while someone is trying to log
in?


-- 
greg

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Subject: Re: Cannot *start* server because of a typo in pg_hba.conf
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