Bug report

============================================================================
                        POSTGRESQL BUG REPORT TEMPLATE
============================================================================


Your name               :       Robert Bruccoleri
Your email address      :	bruc@acm.org


System Configuration
---------------------
  Architecture (example: Intel Pentium)         : SGI Origin 3000

  Operating System (example: Linux 2.0.26 ELF)  : Irix 6.5.18

  PostgreSQL version (example: PostgreSQL-7.3.2):   PostgreSQL-7.3.2 and possibly 7.2.1

  Compiler used (example:  gcc 2.95.2)          : MIPS Pro 7.4 and MIPS Pro 7.3.1.3, 64 bit compilation model.


Please enter a FULL description of your problem:
------------------------------------------------

The PostgreSQL backend core dumps reproducibly with a set of LOCK commands that
would normally deadlock.

The following debugging session on the core dump shows some details:

nunu postgres 101 >>dbx /pg/postgresql-7.3.2/bin/postgres
dbx version 7.3.3 (78517_Dec16 MR) Dec 16 2001 07:45:22
Core from signal SIGBUS: Bus error
file foo.dbx already exists, appending
[3] record input foo.dbx (0 lines)
warning: file foo.dbx already exists, appending
[4] record output foo.dbx (0 lines)
(dbx) where
>  0 ExpandConstraints(constraints = 0x1041ad58, nConstraints = 1) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/deadlock.c":586, 0x101df1ec]
   1 TestConfiguration(startProc = 0x8006483ebf8) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/deadlock.c":322, 0x101de90c]
   2 DeadLockCheckRecurse(proc = 0x8006483ebf8) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/deadlock.c":246, 0x101de698]
   3 DeadLockCheckRecurse(proc = 0x8006483ebf8) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/deadlock.c":280, 0x101de828]
   4 DeadLockCheck(proc = 0x8006483ebf8) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/deadlock.c":192, 0x101de4a4]
   5 CheckDeadLock() ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/proc.c":843, 0x101dd9d0]
   6 handle_sig_alarm(postgres_signal_arg = 14) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/proc.c":1145, 0x101de280]
   7 _sigtramp(0xc, 0x1, 0xda710a4, 0x7f7f7f7f7f7f7f7f, 0x1034fe50, 0xe, 0x1, 0x9) ["/xlv14/patches/4847/work/irix/lib/libc/libc_64_M4/signal/sigtramp.s":71, 0xda6250c]
   8 __syscall(0x41d, 0x2, 0xf1, 0x1, 0x72, 0x75, 0x80044833070, 0x1) ["/xlv14/patches/4847/work/irix/lib/libc/libc_64_M4/sys/syscall.s":20, 0xda93178]
   9 _semop(0xf1, 0xffffffcca30, 0x1, 0x1, 0x72, 0x75, 0x80044833070, 0x1) ["/xlv14/patches/4847/work/irix/lib/libc/libc_64_M4/sys/semsys.c":62, 0xda946a4]
   10 PGSemaphoreLock(sema = 0x8006483ec08, interruptOK = '\001') ["/pg/postgresql-7.3.2/src/backend/port/pg_sema.c":434, 0x101a8d8c]
   11 ProcSleep(lockMethodTable = 0x800648367c8, lockmode = 8, lock = 0x80064861480, holder = 0x800648625d0) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/proc.c":673, 0x101dd5e8]
   12 WaitOnLock(lockmethod = 1, lockmode = 8, lock = 0x80064861480, holder = 0x800648625d0) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/lock.c":896, 0x101daa34]
   13 LockAcquire(lockmethod = 1, locktag = 0xffffffccc58, xid = 5681, lockmode = 8, dontWait = '') ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/lock.c":685, 0x101da294]
   14 LockRelation(relation = 0x104bc560, lockmode = 8) ["/pg/postgresql-7.3.2/src/backend/storage/lmgr/lmgr.c":133, 0x101d81c8]
   15 relation_open(relationId = 23467, lockmode = 8) ["/pg/postgresql-7.3.2/src/backend/access/heap/heapam.c":477, 0x1005b46c]
   16 LockTableCommand(lockstmt = 0x104c12d8) ["/pg/postgresql-7.3.2/src/backend/commands/lockcmds.c":61, 0x101061e4]
   17 ProcessUtility(parsetree = 0x104c12d8, dest = Remote=2, completionTag = 0xffffffccf18 = "") ["/pg/postgresql-7.3.2/src/backend/tcop/utility.c":806, 0x101eb498]
   18 pg_exec_query_string(query_string = 0x104c1010, dest = Remote=2, parse_context = 0x104bf120) ["/pg/postgresql-7.3.2/src/backend/tcop/postgres.c":789, 0x101e6cc8]
   19 PostgresMain(argc = 4, argv = 0xffffffcd0c0, username = 0x103bf1a9 = "bruc") ["/pg/postgresql-7.3.2/src/backend/tcop/postgres.c":2013, 0x101e8be4]
   20 DoBackend(port = 0x103bf078) ["/pg/postgresql-7.3.2/src/backend/postmaster/postmaster.c":2302, 0x101ad4c4]
   21 BackendStartup(port = 0x103bf078) ["/pg/postgresql-7.3.2/src/backend/postmaster/postmaster.c":1924, 0x101ac8ec]
   22 ServerLoop() ["/pg/postgresql-7.3.2/src/backend/postmaster/postmaster.c":1027, 0x101aae58]
   23 PostmasterMain(argc = 8, argv = 0x103b3f98) ["/pg/postgresql-7.3.2/src/backend/postmaster/postmaster.c":788, 0x101aa6c4]
   24 main(argc = 8, argv = 0xffffffcdde8) ["/pg/postgresql-7.3.2/src/backend/main/main.c":210, 0x1015fed4]
   25 __start() ["/xlv55/kudzu-apr12/work/irix/lib/libc/libc_64_M4/csu/crt1text.s":177, 0x10032c78]
(dbx) l 570,590
   570                                    int nConstraints)
   571  {
   572          int                     nWaitOrderProcs = 0;
   573          int                     i,
   574                                  j;
   575  
   576          nWaitOrders = 0;
   577  
   578          /*
   579           * Scan constraint list backwards.      This is because the last-added
   580           * constraint is the only one that could fail, and so we want to test
   581           * it for inconsistency first.
   582           */
   583          for (i = nConstraints; --i >= 0;)
   584          {
   585                  PGPROC     *proc = constraints[i].waiter;
 * 586                  LOCK       *lock = proc->waitLock;
   587  
   588                  /* Did we already make a list for this lock? */
   589                  for (j = nWaitOrders; --j >= 0;)
   590                  {
(dbx) p proc
0x7f7f7f7f7f7f7f7f 
(dbx) p constraints[0]
struct {waiter = 0x7f7f7f7f7f7f7f7f, blocker = 0x7f7f7f7f7f7f7f7f, pred = 2139062143, link = 2139062143} 
(dbx) p constraints[1]
struct {waiter = 0x7f7f7f7f7f7f7f7f, blocker = 0x7f7f7f7f7f7f7f7f, pred = 2139062143, link = 2139062143} 
(dbx) p i
0 
(dbx) p nConstraints
1 

Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible: 
----------------------------------------------------------------------

0) Create a user named tilfordc with all rights.
1) Construct a database using the 'maptracker.sql' schema attached to this message.
   Use the name, 'maptracker', as an example.
2) Start two psql sessions on maptracker. Issue "BEGIN;" commands in both.
3) In session 1, type "lock mapping;".
4) In session 2, type "lock location;" and then "lock mapping;"
5) In session 1, type "lock location;". The backend will crash in a few seconds.


If you know how this problem might be fixed, list the solution below:
---------------------------------------------------------------------

+-----------------------------+------------------------------------+
| Robert E. Bruccoleri, Ph.D. | email: bruc@acm.org                |
| President, Congenomics Inc. | URL:   http://www.congen.com/~bruc |
| P.O. Box 314                | Phone: 609 818 7251                | 
| Pennington, NJ 08534        |                                    |
+-----------------------------+------------------------------------+