Re: pqReadData() -- backend closed the channel unexpectedly.

I got an email saying that my message did not make it to the list, so I
am posting again. Hopefully it will go through this time.

I am running PostgreSQL 7.1.2 on FreeBSD 4.3
This is an old 486 with only 12MB memory.

I am able to create databases and insert and retrieve data,
but when I try to query on the structure of the database
I am getting this error:

signin=# \d person_personid_seq
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!# \q


I have never seen that prompt before (!#)

I turned up debugging and here is (some) of the output:

<snip>
DEBUG: database system is in production state
DEBUG: proc_exit(0)
DEBUG: shmem_exit(0)
DEBUG: exit(0)
postmaster: reaping dead processes...
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
<snip>
postmaster: ServerLoop: handling writing 4
postmaster: BackendStartup: pid 635 user lee db lee socket 4
postmaster child[635]: starting with (postgres -d5 -d 5 -v131072 -p lee )
FindExec: searching PATH ...
FindExec: found "/usr/local/bin/postgres" using PATH
DEBUG: connection: host=[local] user=lee database=lee
DEBUG: InitPostgres
DEBUG: StartTransactionCommand
DEBUG: query: SELECT usesuper FROM pg_user WHERE usename = 'lee'
<snip>
DEBUG: ProcessQuery
DEBUG: CommitTransactionCommand
DEBUG: proc_exit(0)
DEBUG: shmem_exit(0)
DEBUG: exit(0)
postmaster: reaping dead processes...
postmaster: CleanupProc: pid 635 exited with status 0
postmaster: ServerLoop: handling reading 4
<snip>
postmaster: ServerLoop: handling writing 4
postmaster: BackendStartup: pid 642 user lee db signin socket 4
postmaster child[642]: starting with (postgres -d5 -d 5 -v131072 -p signin )
FindExec: searching PATH ...
FindExec: found "/usr/local/bin/postgres" using PATH
DEBUG: connection: host=[local] user=lee database=signin
DEBUG: InitPostgres
DEBUG: proc_exit(0)
DEBUG: shmem_exit(0)
DEBUG: exit(0)
postmaster: reaping dead processes...
postmaster: CleanupProc: pid 639 exited with status 0
<snip>
postmaster: reaping dead processes...
postmaster: CleanupProc: pid 642 exited with status 132
Server process (pid 642) exited with status 132 at Mon Jul 23 09:46:26 2001
Terminating any active server processes...
Server processes were terminated at Mon Jul 23 09:46:26 2001
Reinitializing shared memory and semaphores
invoking IpcMemoryCreate(size=1236992)
DEBUG: database system was interrupted at 2001-07-23 09:44:48 EDT
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
The Data Base System is starting up
postmaster: ServerLoop: handling writing 4
DEBUG: CheckPoint record at (0, 3580356)
DEBUG: Redo record at (0, 3580356); Undo record at (0, 0); Shutdown TRUE
DEBUG: NextTransactionId: 1362; NextOid: 101105
DEBUG: database system was not properly shut down; automatic recovery in progr
DEBUG: ReadRecord: record with zero len at (0, 3580420)
DEBUG: redo is not required
DEBUG: database system is in production state
DEBUG: proc_exit(0)
DEBUG: shmem_exit(0)
DEBUG: exit(0)
postmaster: reaping dead processes...
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
<snip>
DEBUG: StartTransactionCommand
DEBUG: query: SELECT relhasindex, relkind, relchecks, reltriggers, relhasrules
FROM pg_class WHERE relname='person_personid_seq'
DEBUG: parse tree: { QUERY :command 1 :utility <> :resultRelation 0 :into <>
<snip>
<> :sortClause ({ SORTCLAUSE :tleSortGroupRef 1 :sortop 95 }) :limitOffset <> :l
imitCount <> :setOperations <> :resultRelations ()}
postmaster: reaping dead processes...
postmaster: CleanupProc: pid 654 exited with status 132
Server process (pid 654) exited with status 132 at Mon Jul 23 09:47:37 2001
Terminating any active server processes...
Server processes were terminated at Mon Jul 23 09:47:37 2001
Reinitializing shared memory and semaphores
invoking IpcMemoryCreate(size=1236992)
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
postmaster: ServerLoop: handling reading 4
The Data Base System is starting up
postmaster: ServerLoop: handling writing 4
DEBUG: database system was interrupted at 2001-07-23 09:46:29 EDT
DEBUG: CheckPoint record at (0, 3580420)
DEBUG: Redo record at (0, 3580420); Undo record at (0, 0); Shutdown TRUE
DEBUG: NextTransactionId: 1362; NextOid: 101105
DEBUG: database system was not properly shut down; automatic recovery in progr
DEBUG: ReadRecord: record with zero len at (0, 3580484)
DEBUG: redo is not required
DEBUG: database system is in production state
DEBUG: proc_exit(0)
DEBUG: shmem_exit(0)
DEBUG: exit(0)
postmaster: reaping dead processes...

Could running out of memory cause the backend to die like that? I have the
exact same schema and data loaded on another 486 (with 64M RAM) and it
runs without any hitches.

If it is a memory problem, any hints on tuning the system so that it
can run without crashing?