Problem with locks

I'm debugging this problem with stalled transactions waiting on locks which
have already been granted and I'm puzzled by something. What is this PGPROC
entry from?

It's not a real process (pid is 0) and it's not garbage either (prev and next
both point to a real PGPROC entry, namely MyProc which as you can see is
waiting for this PGPROC).

(gdb) p *(PGPROC*)(ShmemBase + MyProc->links.prev)
$2 = {links = {prev = 2520941752, next = 2520941752}, sem = {semId = 1, semNum = 0}, waitStatus = 0, xid = 0, xmin = 0, pid = 0,
databaseId = 0, roleId = 0, inCommit = 0 '\0', inVacuum = 0 '\0', isAutovacuum = 0 '\0', lwWaiting = 0 '\0', lwExclusive = 2 '\002',
lwWaitLink = 0x0, waitLock = 0x2, waitProcLock = 0x0, waitLockMode = 0, heldLocks = 0, myProcLocks = {{prev = 0, next = 1}, {
prev = 4294967296, next = 0}, {prev = 3028785127, next = 360654}, {prev = 73183493944770560, next = 137438953600}, {
prev = 2520929504, next = 2520929072}, {prev = 2520940536, next = 2520940536}, {prev = 1, next = 0}, {prev = 0,
next = 4294967296}, {prev = 4294967296, next = 0}, {prev = 2, next = 0}, {prev = 0, next = 0}, {prev = 1, next = 4294967296}, {
prev = 0, next = 4000475635}, {prev = 360707, next = 73183493944770560}, {prev = 128, next = 2520933680}, {prev = 2520933680,
next = 2520914616}}, subxids = {overflowed = -72 '�', nxids = 0, xids = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 1, 0, 0, 1626942462, 0, 16384, 16430, 0, 16777216, 2, 0, 2520930944, 0, 2520930944, 0, 2520914784, 0, 2520914784,
0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0}}}
(gdb) p MyProc-ShmemBase
$3 = (PGPROC *) 0xff9ac36e36e264b8
(gdb) p (unsigned long)MyProc-ShmemBase
$4 = 2520941752

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com