postgres server crashes unexpectedly

hi all,

we've had a db to stop working for some reason and have searched through google to it's ends to no avail. we have reindexed the database and system database as tried to determine other things that would keep it from working... again, to no avail.

this just started occuring about 2 weeks ago and below is a recent snippet of error log that we have. any idea what would/could be causing these crashes? any response is much appreciated as this is not a time-critial issue for us.

thanks!

chadwick

error log:

LOG: redo is not required
LOG: database system is ready
PANIC: corrupted item pointer: offset = 0, size = 0
LOG: autovacuum process (PID 3037) was terminated by signal 6
LOG: terminating any other active server processes
LOG: all server processes terminated; reinitializing
LOG: database system was interrupted at 2008-03-18 02:55:30 PDT
LOG: checkpoint record is at 25/6068AE30
LOG: redo record is at 25/6068AE30; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/414366728; next OID: 240102
LOG: next MultiXactId: 1132; next MultiXactOffset: 2431
LOG: database system was not properly shut down; automatic recovery in progress
LOG: record with zero length at 25/6068AE80
LOG: redo is not required
LOG: database system is ready
PANIC: corrupted item pointer: offset = 0, size = 0
LOG: autovacuum process (PID 3045) was terminated by signal 6
LOG: terminating any other active server processes
LOG: all server processes terminated; reinitializing
LOG: database system was interrupted at 2008-03-18 02:56:31 PDT
LOG: checkpoint record is at 25/6068AE80
LOG: redo record is at 25/6068AE80; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/414366728; next OID: 240102
LOG: next MultiXactId: 1132; next MultiXactOffset: 2431
LOG: database system was not properly shut down; automatic recovery in progress
LOG: record with zero length at 25/6068AED0
LOG: redo is not required
LOG: database system is ready
PANIC: corrupted item pointer: offset = 0, size = 0
LOG: autovacuum process (PID 3072) was terminated by signal 6
LOG: terminating any other active server processes
WARNING: terminating connection because of crash of another server process
DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
HINT: In a moment you should be able to reconnect to the database and repeat your command.
LOG: all server processes terminated; reinitializing
LOG: database system was interrupted at 2008-03-18 02:57:32 PDT
LOG: checkpoint record is at 25/6068AED0
LOG: redo record is at 25/6068AED0; undo record is at 0/0; shutdown TRUE
LOG: next transaction ID: 0/414366728; next OID: 240102
LOG: next MultiXactId: 1132; next MultiXactOffset: 2431
LOG: database system was not properly shut down; automatic recovery in progress
LOG: record with zero length at 25/6068AF20
LOG: redo is not required
LOG: database system is ready