updating to 7.4.13 helped it appears

It appears that upgrading to 7.4.13 helped the problem we were having
with the postgres process terminating.  We still are having the problem,
but it does appear to be different, based on the output of backtraces.
The core files are much larger and there does seem to be a common thread
amongst most of them. I've attached one to see if anyone has any ideas
as to what our problem might be.  Suggestions would be appreciated.

--
Until later, Geoffrey

Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety.
  - Benjamin Franklin
Using host libthread_db library "/lib/tls/libthread_db.so.1".
Core was generated by `postgres: msanchez exp 198.212.166.29 SELECT  '.
Program terminated with signal 11, Segmentation fault.
#0  0x0815d950 in cost_mergejoin (path=0x836f20c, root=0x8370708)
    at costsize.c:915
915            if (rescannedtuples < 0)
#0  0x0815d950 in cost_mergejoin (path=0x836f20c, root=0x8370708)
    at costsize.c:915
#1  0x0815d98c in cost_mergejoin (path=0x836f20c, root=0x8370300)
    at costsize.c:932
#2  0x0815d98c in cost_mergejoin (path=0x836f20c, root=0x836f2ec)
    at costsize.c:932
#3  0x0815d8c1 in cost_mergejoin (path=0x836f20c, root=0x775360)
    at costsize.c:878
#4  0x0815c428 in clauselist_selectivity (root=0x827d6e4, clauses=0xfeff7798,
    varRelid=-16812072, jointype=135970173) at clausesel.c:203
#5  0x081637f5 in get_cheapest_path_for_pathkeys (paths=0x827d6e4,
    pathkeys=0x882eeb0, cost_criterion=7) at pathkeys.c:586
#6  0x081abd7d in ProcessUtility (parsetree=0x835ea10, dest=0x882ee54,
    completionTag=0xa <Address 0xa out of bounds>) at utility.c:611
#7  0x081ac1ff in ProcessUtility (parsetree=0xfeff7850, dest=0x88af7e0,
    completionTag=0x88af408 "\v") at utility.c:793
#8  0x081082c4 in CreateTrigger (stmt=0x88af588, forConstraint=-100 '\234')
    at trigger.c:155
#9  0x08109e30 in CopyTriggerDesc (trigdesc=0x88af588) at trigger.c:922
#10 0x0810aa4b in ExecBSDeleteTriggers (estate=0x88af828, relinfo=0x88af408)
    at trigger.c:1324
#11 0x0810ae71 in ExecASUpdateTriggers (estate=0x88af380, relinfo=0x8112de0)
    at trigger.c:1462
#12 0x08112ec9 in AlterUserSet (stmt=0x88af380) at user.c:1002
#13 0x08106d66 in createForeignKeyTriggers (rel=0x88af380, fkconstraint=0x1,
    constrOid=141463696) at tablecmds.c:3697
#14 0x08113718 in CreateGroup (stmt=0x88af2f8) at user.c:1273
#15 0x08106e11 in createForeignKeyTriggers (rel=0x88af2f8, fkconstraint=0x413,
    constrOid=4278155864) at tablecmds.c:3714
#16 0x081055fd in AlterTableAddCheckConstraint (rel=0x88af1a8,
    constr=0x88af2f8) at tablecmds.c:2951
#17 0x081049d8 in AlterTableAlterOids (myrelid=139861992, recurse=-88 '�',
    setOid=-40 '�') at tablecmds.c:2513
#18 0x0817c33b in BackendFork (port=0x8360fd8) at postmaster.c:2485
#19 0x0817c113 in BackendFork (port=0x8360fd8) at postmaster.c:2403
#20 0x081788d3 in PGSemaphoreLock (sema=0x835cbc0, interruptOK=0 '\0')
    at pg_sema.c:424
#21 0x0817b1c1 in pmdie (postgres_signal_arg=4) at postmaster.c:1701
#22 0x08154c40 in _readConst () at readfuncs.c:377
#23 0x08154633 in _readResdom () at readfuncs.c:311
#24 0x08152b98 in _outAExpr (str=0x2, node=0x1) at outfuncs.c:1366
#25 0x0815225e in _outIndexElem (str=0x5, node=0x830d6b8) at outfuncs.c:1208
#26 0x08121f63 in ExecEndNode (node=0x5) at execProcnode.c:499
#27 0x0065479a in ?? ()
#28 0x00000005 in ?? ()
#29 0xfeff8c64 in ?? ()
#30 0xfeff8c7c in ?? ()
#31 0x00000000 in ?? ()
#32 0x00774a78 in ?? ()
#33 0x0013a020 in ?? ()
#34 0x081fbd18 in interval_part (fcinfo=0x8121d30) at timestamp.c:3374
#35 0x0806fd51 in nocachegetattr (tuple=) at heaptuple.c:409