FailedAssertion("!(PrivateRefCount[i] == 0)", File: "bufmgr.c", Line: 1741

pg 9.2 git master
AMD 8120 (8-core) / 6 GB memory / Centos 6.2

I have experimented a bit with dropping a table from master, then querying that table from a
sync-rep slave. It is a little worrying that this, the first test I tried, crashes the slave.

There are two instance on one machine, head1 (=master) and head2 (=sync-rep slave).

First, I generated a tab-separated file, a one off, to be used in the test:

echo "
copy (
select
repeat('X',20) as c1
, repeat('X',20) as c2
, repeat('X',20) as c3
, repeat('X',20) as c4
, repeat('X',20) as c5
from generate_series(1, 200000)
)
to stdout
csv delimiter E'\t';
" | $HOME/pg_stuff/pg_installations/pgsql.head1/bin/psql -p 6564 -d testdb > dropload_copy.txt

That txt file is zipped, and the actual test consists of a bash while loop which
1. drops the table
2. loads the file into the table
3. Either:
a. nothing
b. does a select count(*) on the table

So, it repeats the following:

zcat dropload_copy.txt.gz \
| grep -v '^#' \
| $HOME/pg_stuff/pg_installations/pgsql.head1/bin/psql -p 6564 -d testdb -c "
drop table if exists t;
create table t (
c1 text,
c2 text,
c3 text,
c4 text,
c5 text
);
copy t from stdin csv delimiter E'\t';
analyze t;";

PAUSE_DURATION=0
PSQL=$HOME/pg_stuff/pg_installations/pgsql.head1/bin/psql

if [[ 0 -eq 1 ]]; # ON-OFF switch
then

echo "sleep $PAUSE_DURATION"
sleep $PAUSE_DURATION;
(
echo "select current_setting('port') port, count(*) from $schema.$table" | $PSQL -qtXp 6564 -d
testdb # master
echo "select current_setting('port') port, count(*) from $schema.$table" | $PSQL -qtXp 6565 -d
testdb # wal_receiver_01
#echo "select current_setting('port') port, count(*) from $schema.$table" | $PSQL -qtXp 6566 -d
testdb # wal_receiver_02
) | grep -v '^$'
fi

This runs fine for hours on end, as long as the ON-OFF switch is disabled.

But when that if-block is added the client crashes after a while (sometimes almost immediately; it
never survives longer then 20 minutes):

2012-05-26 10:44:22.617 CEST 10274 ERROR: could not fsync file "base/21268/32807": No such file
or directory
2012-05-26 10:44:28.465 CEST 10274 ERROR: could not fsync file "base/21268/32867": No such file
or directory
2012-05-26 10:44:28.587 CEST 10270 FATAL: could not open file "base/21268/32994": No such file or
directory
2012-05-26 10:44:28.588 CEST 10270 CONTEXT: writing block 2508 of relation base/21268/32994
xlog redo multi-insert (init): rel 1663/21268/33006; blk 3117; 58 tuples
TRAP: FailedAssertion("!(PrivateRefCount[i] == 0)", File: "bufmgr.c", Line: 1741)
2012-05-26 10:44:31.131 CEST 10269 LOG: startup process (PID 10270) was terminated by signal 6:
Aborted
2012-05-26 10:44:31.131 CEST 10269 LOG: terminating any other active server processes

Crazy scenario , I'll admit, but surely this shouldn't be able to crash the client?

I attach the logfiles of master(=head1) and slave (=head2). It show how the above ran for an hour
without problems (while the ON/OFF switch was disabled), and how the crash came quickly when I
switched it on (to add the select count(*) statements).

Erik Rijkers