Bug report

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POSTGRESQL BUG REPORT TEMPLATE
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Your name : Robert Bruccoleri
Your email address : bruc@acm.org

System Configuration
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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:
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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
warning: file foo.dbx already exists, appending
[4]: record output foo.dbx (0 lines) (dbx) where
(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:
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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:
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+-----------------------------+------------------------------------+
| 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        |                                    |
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