Re: BUG #2033: Assertion Failure: File: "procarray.c",

A backtrace from one of the cores would be a good start.

On Wed, Nov 09, 2005 at 07:44:01AM -0800, Joel Stevenson wrote:
> Sorry, I realize this bug is a little lean on details.
>
> PG is set up to serve multiple concurrent processes in a work queue
> fashion, therefore these processes are in contention for the same
> resources as the queue is basically a FIFO and I'm using SELECT ...
> FOR UPDATE NOWAIT in each client to grab the next work segment in
> line.
>
> I've been running the setup on 8.1b3 and 8.1RC1 without this
> particular Assertion failure, but had not been using the NOWAIT flag
> until today. During a period of perhaps 20 processes operating on
> the queue it looks like postgres failed this assertion 17 times, the
> first coming very shortly after the processes began and the rest
> following in quick succession.
>
> I do have the core files if further info is needed from them.
>
> Thanks,
> Joel
>
>
> At 3:19 PM +0000 11/9/05, Joel Stevenson wrote:
> >The following bug has been logged online:
> >
> >Bug reference: 2033
> >Logged by: Joel Stevenson
> >Email address: joelstevenson(at)mac(dot)com
> >PostgreSQL version: 8.1.0
> >Operating system: RHEL 3 update 6
> >Description: Assertion Failure: File: "procarray.c", Line: 492
> >Details:
> >
> >Hi,
> >
> >I'm running into an Assertion failure this morning w/8.1.0. I believe it
> >is
> >related to using the NOWAIT flag. Here is the log message:
> >
> >TRAP: FailedAssertion("!(serializable ? !((MyProc->xmin) !=
> >((TransactionId)
> >0))
> > : ((MyProc->xmin) != ((TransactionId) 0)))", File: "procarray.c", Line:
> >492)
> >
> >
> >Postgres was configured using both --enable-debug and --enable-cassert.
> >Full config options were:
> >
> >./configure CFLAGS=-O2 -pipe --with-perl --with-openssl
> >--enable-thread-safety --enable-debug --enable-cassert
> >--with-includes=/usr/kerberos/include
> >
> >Some non-default postgresql.conf params:
> >max_connections = 150
> >ssl = on
> >shared_buffers = 4000
> >work_mem = 102400
> >maintenance_work_mem = 131072
> >max_stack_depth = 4096
> >commit_delay = 100
> >checkpoint_segments = 5
> >effective_cache_size = 173015
> >stats_start_collector = on
> >stats_command_string = on
> >stats_block_level = on
> >stats_row_level = on
> >stats_reset_on_server_start = on
> >autovacuum = on
> >autovacuum_analyze_scale_factor = 0.1
> >
> >I've removed the 'NOWAIT' for the time being, but thought I should mention
> >the issue.
> >
> >Thanks,
> >Joel
> >
> >---------------------------(end of broadcast)---------------------------
> >TIP 4: Have you searched our list archives?
> >
> > http://archives.postgresql.org
>
>
> ---------------------------(end of broadcast)---------------------------
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>

--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461