panic: index siblings mismatch

Hello,

today I recognized an error while playing with pgpool-II 2.1 and
postgresql 8.3.5 (on 64bit linux).
I really don't know if the error is caused by pgpool or if it's
postgresql-related...?!?

There are up to 200 active connections in parallel and thereby sometimes
high load (with high write:read ratio, peak level ~60% write).
Can this be a problem in such a usage scenario, are there some
limitations in pgpool-II <-> number of connections / load ???

any hints are much appreciated, since we don't know what happened...

thanks in advance...::GERD::...

LOG DETAILS:

a) postgresql log of second db node where the error occured
b) pgpool log

a)
==================================================================
2009-03-10 11:16:33 CET [11008]: [1-1] PANIC: right sibling's left-link
doesn't match: block 695 links to 785 instead of expected 694 in index
"PartyAddress_index"
2009-03-10 11:16:33 CET [11008]: [2-1] STATEMENT: INSERT INTO
"PartyAddress" ("Name1", "Name2", "Street1", "Street2", "
City", "Postcode", "Region", "Country", "Timezone", "Qualifier",
"Compressed", "PositionId") VALUES (E'Testing', E'', E'
Public street', E'', E'somewhere', E'12345', E'-', E'DE', E'UTC+1',
E'address.loading', FALSE, NULL); select lastval()
2009-03-10 11:16:33 CET [29026]: [3-1] LOG: server process (PID 11008)
was terminated by signal 6: Aborted
2009-03-10 11:16:33 CET [29026]: [4-1] LOG: terminating any other
active server processes
2009-03-10 11:16:33 CET [10978]: [5-1] WARNING: terminating connection
because of crash of another server process
2009-03-10 11:16:33 CET [10978]: [6-1] DETAIL: The postmaster has
commanded this server process to roll back the curren
t transaction and exit, because another server process exited abnormally
and possibly corrupted shared memory.
2009-03-10 11:16:33 CET [10978]: [7-1] HINT: In a moment you should be
able to reconnect to the database and repeat you
r command.
2009-03-10 11:16:33 CET [10947]: [1-1] WARNING: terminating connection
because of crash of another server process
.....
.....
2009-03-10 11:16:33 CET [29026]: [6-1] LOG: all server processes
terminated; reinitializing
2009-03-10 11:16:33 CET [11015]: [1-1] LOG: database system was
interrupted; last known up at 2009-03-10 11:09:10 CET
2009-03-10 11:16:33 CET [11015]: [2-1] LOG: starting archive recovery
2009-03-10 11:16:33 CET [11015]: [3-1] LOG: restore_command = 'cp
/exchange/wal_from_iweblin/%f %p'
cp: cannot stat `/exchange/wal_from_iweblin/00000003.history': No such
file or directory
cp: cannot stat `/exchange/wal_from_iweblin/0000000300000001000000AA':
No such file or directory
2009-03-10 11:16:33 CET [11015]: [4-1] LOG: automatic recovery in progress
2009-03-10 11:16:33 CET [11015]: [5-1] LOG: redo starts at 1/AABEBFA8
2009-03-10 11:16:33 CET [11015]: [6-1] LOG: unexpected pageaddr
0/36BEE000 in log file 1, segment 170, offset 12509184
2009-03-10 11:16:33 CET [11015]: [7-1] LOG: redo done at 1/AABED938
2009-03-10 11:16:33 CET [11015]: [8-1] LOG: last completed transaction
was at log time 2009-03-10 11:15:17.533913+01
cp: cannot stat `/exchange/wal_from_iweblin/0000000300000001000000AA':
No such file or directory
cp: cannot stat `/exchange/wal_from_iweblin/00000004.history': No such
file or directory
2009-03-10 11:16:33 CET [11015]: [9-1] LOG: selected new timeline ID: 4
cp: cannot stat `/exchange/wal_from_iweblin/00000003.history': No such
file or directory
2009-03-10 11:16:33 CET [11015]: [10-1] LOG: archive recovery complete
2009-03-10 11:16:33 CET [11015]: [11-1] LOG: checkpoint starting:
shutdown immediate
2009-03-10 11:16:34 CET [11015]: [12-1] LOG: checkpoint complete: wrote
4 buffers (0.0%); 0 transaction log file(s) added, 0 removed, 0
recycled; write=0.005 s, sync=0.086 s, total=0.242 s
2009-03-10 11:16:34 CET [11023]: [1-1] LOG: autovacuum launcher started
2009-03-10 11:16:34 CET [29026]: [7-1] LOG: database system is ready to
accept connections
=======================================

b)
==========================================
2009-03-10 11:16:23 DEBUG: pid 19059: read kind from frontend X(58)
2009-03-10 11:16:31 DEBUG: pid 27107: read kind from frontend Q(51)
2009-03-10 11:16:31 LOG: pid 27107: statement: SELECT d.oid, datname
as name, pg_get_userbyid(datdba) as owner, ds.des
cription, pg_encoding_to_char(encoding) as dbencoding, datistemplate,
datlastsysoid, datconfig, s.spcname as tblspace, d
atconnlimit AS conlimit FROM pg_database d LEFT OUTER JOIN
pg_description ds ON d.oid = ds.objoid LEFT OUTER JOIN pg_tab
lespace s ON d.dattablespace = s.oid WHERE datname = 'test'

2009-03-10 11:16:31 DEBUG: pid 27107: waiting for backend 0 completing
the query
2009-03-10 11:16:31 DEBUG: pid 27107: read_kind_from_backend: read kind
from 0 th backend T NUM_BACKENDS: 1
2009-03-10 11:16:31 DEBUG: pid 27107: pool_process_query: kind from
backend: T
2009-03-10 11:16:31 DEBUG: pid 27107: read_kind_from_backend: read kind
from 0 th backend D NUM_BACKENDS: 1
2009-03-10 11:16:31 DEBUG: pid 27107: pool_process_query: kind from
backend: D
2009-03-10 11:16:31 DEBUG: pid 27107: read_kind_from_backend: read kind
from 0 th backend C NUM_BACKENDS: 1
2009-03-10 11:16:31 DEBUG: pid 27107: pool_process_query: kind from
backend: C
2009-03-10 11:16:31 DEBUG: pid 27107: read_kind_from_backend: read kind
from 0 th backend Z NUM_BACKENDS: 1
2009-03-10 11:16:31 DEBUG: pid 27107: pool_process_query: kind from
backend: Z
2009-03-10 11:16:31 DEBUG: pid 27107: pool_read_message_length: slot: 0
length: 5
2009-03-10 11:16:31 DEBUG: pid 27107: ReadyForQuery: message length: 5
2009-03-10 11:16:31 DEBUG: pid 27107: ReadyForQuery: transaction state: I
2009-03-10 11:16:31 DEBUG: pid 27107: end_load_balance: end load balance
mode
2009-03-10 11:16:31 DEBUG: pid 27107: read kind from frontend X(58)
2009-03-10 11:16:36 DEBUG: pid 27107: I am 27107 accept fd 5
2009-03-10 11:16:36 LOG: pid 27107: connection received:
host=172.28.1.126 port=1946
2009-03-10 11:16:36 DEBUG: pid 27107: Protocol Major: 1234 Minor: 5679
database: user:
2009-03-10 11:16:36 DEBUG: pid 27107: SSLRequest: sent N; retry startup
2009-03-10 11:16:36 DEBUG: pid 27107: Protocol Major: 3 Minor: 0
database: test user: test
2009-03-10 11:16:36 DEBUG: pid 27107: new_connection: connecting 0 backend
2009-03-10 11:16:36 DEBUG: pid 27107: new_connection: connecting 1 backend
2009-03-10 11:16:36 DEBUG: pid 27107: new_connection: skipping slot 1
because backend_status = 3