segfaults / backend crashing

I'm having a problem with the backend occasionally crashing.

I have interfaces with the database in two different applications -- a
web viewer using JDBC and an insertion routine written using the c
libraries. It makes fairly heavy use of the tsearch protocol. (I
haven't been able to figure out anything repetitious, it happens at
different times, and after I get a new connection the exact search
query or insertion string works fine).

All that's printed to the postgres log is this:
2003-09-02 10:41:18 [428] LOG: server process (pid 479) was
terminated by signal 11
2003-09-02 10:41:18 [428] LOG: terminating any other active server
processes
2003-09-02 10:41:18 [428] LOG: all server processes terminated;
reinitializing shared memory and semaphores
2003-09-02 10:41:18 [510] LOG: database system was interrupted at
2003-09-02 10:17:38 CDT
2003-09-02 10:41:18 [428] LOG: all server processes terminated;
reinitializing shared memory and semaphores
2003-09-02 10:41:18 [510] LOG: database system was interrupted at
2003-09-02 10:17:38 CDT
2003-09-02 10:41:18 [510] LOG: checkpoint record is at 0/53E94490
2003-09-02 10:41:18 [510] LOG: redo record is at 0/53E94490; undo
record is at 0/0; shutdown TRUE
2003-09-02 10:41:18 [510] LOG: next transaction id: 127192; next
oid: 1562034
2003-09-02 10:41:18 [510] LOG: database system was not properly
shut down; automatic recovery in progress
2003-09-02 10:41:18 [510] LOG: redo starts at 0/53E944D0
2003-09-02 10:41:18 [510] LOG: ReadRecord: record with zero length
at 0/53EA28E0
2003-09-02 10:41:18 [510] LOG: redo done at 0/53EA282C
2003-09-02 10:41:20 [510] LOG: database system is ready

The crash log associated with that crash isn't particularly useful, at
least to me:
Date/Time: 2003-09-02 10:41:17 -0500
OS Version: 10.2.6 (Build 6L60)
Host: dahak.local.

Command: postmaster
PID: 479

Exception: EXC_BAD_ACCESS (0x0001)
Codes: KERN_INVALID_ADDRESS (0x0001) at 0xffffe640

Thread 0 Crashed:

PPC Thread State:
srr0: 0xbfffe5e0 srr1: 0x0200f930 vrsave: 0x00000000
xer: 0x00000000 lr: 0xbfffe5e0 ctr: 0x90010000 mq: 0x00000000
r0: 0xbfffe5e0 r1: 0xbfffe5d0 r2: 0x8fe4e3e0 r3: 0x00000000
r4: 0x0088ec1c r5: 0x00000007 r6: 0x00000006 r7: 0x0088eba4
r8: 0x0000000c r9: 0x00000000 r10: 0x004594d4 r11: 0x008a0150
r12: 0x90010000 r13: 0x00000000 r14: 0x00000000 r15: 0x00000000
r16: 0x00000000 r17: 0x00000000 r18: 0x00000000 r19: 0x00000000
r20: 0x00000000 r21: 0x00000000 r22: 0x00000000 r23: 0x00000000
r24: 0x00000000 r25: 0x00000000 r26: 0xbffffbd4 r27: 0x0000000c
r28: 0x00000002 r29: 0x00459534 r30: 0x00000000 r31: 0x00000000

One of the crashlogs for the JDBC connection looks like this:
Date/Time: 2003-08-13 01:10:21 -0500
OS Version: 10.2.6 (Build 6L60)
Host: dahak.local.

Command: postmaster
PID: 460

Exception: EXC_BAD_ACCESS (0x0001)
Codes: KERN_PROTECTION_FAILURE (0x0002) at 0x00daec05

Thread 0 Crashed:
#0 0x90010070 in __swsetup
#1 0x00d9f8d8 in compare
#2 0x00d9f5a0 in merge
#3 0x00d9f788 in sort
#4 0x00d9fbc0 in create_pool
#5 0x00da1b40 in setup_english_stemmer
#6 0x00da23f4 in initmorph
#7 0x00da43c4 in tsearch
#8 0x00064904 in ExecCallTriggerFunc (trigger.c:1120)
#9 0x00064a7c in ExecBRInsertTriggers (trigger.c:1171)
#10 0x00071018 in ExecInsert (execMain.c:1216)
#11 0x00070ee4 in ExecutePlan (execMain.c:1102)
#12 0x000701fc in ExecutorRun (execMain.c:195)
#13 0x000d31dc in ProcessQuery (pquery.c:247)
#14 0x000d0f8c in pg_exec_query_string (postgres.c:839)
#15 0x000d24d4 in PostgresMain (postgres.c:2020)
#16 0x000b379c in DoBackend (postmaster.c:2293)
#17 0x000b2ff4 in BackendStartup (postmaster.c:1916)
#18 0x000b1ec0 in ServerLoop (postmaster.c:1006)
#19 0x000b19f8 in PostmasterMain (postmaster.c:785)
#20 0x00086670 in main (main.c:210)
#21 0x00001b58 in _start (crt.c:267)
#22 0x000019d8 in start

PPC Thread State:
srr0: 0x90010070 srr1: 0x0200f930 vrsave: 0x00000000
xer: 0x00000000 lr: 0x90010070 ctr: 0x90003900 mq: 0x00000000
r0: 0x90010070 r1: 0xbfffe5f0 r2: 0x00000000 r3: 0x000000e3
r4: 0x00000000 r5: 0x000000e3 r6: 0x0000000a r7: 0x00000020
r8: 0x00000030 r9: 0x000000e3 r10: 0x00000060 r11: 0xa00043ac
r12: 0x90003900 r13: 0x001a0c10 r14: 0x009b4f58 r15: 0xbfffed60
r16: 0x00d37e00 r17: 0x00000000 r18: 0x00000000 r19: 0x00000000
r20: 0x00d367e8 r21: 0x00d385f0 r22: 0x00d36958 r23: 0x00d36af8
r24: 0x00000001 r25: 0x00d36f28 r26: 0x00d36a48 r27: 0x00d385f0
r28: 0xbfffeaa0 r29: 0x00000000 r30: 0x00daebd5 r31: 0x9001000c

Any help would be appreciated.
Jeffrey Melloy
jmelloy(at)visualdistortion(dot)org