[GENERAL] Vacuum hangs

[Patrick Hatcher]

PG: 7.4.5
RH 7.3
Vac_Mem=12mg

Doing a Vacuum Analyze on a table and it's been hanging for at least 2 hours.  I could see no other users hitting the table at the time.  This is the second time this has happened on this particular table and I can't seem to pin point the issue.   If I kill the PID and restart the vacuum analyze it works fine.  Any suggestion where I start searching?  Here is an output from pg_stat_activity and the

mdc_oz=# select * from pg_stat_activity:
datid         | 17145
datname       | mdc_oz
procpid       | 16560
usesysid      | 2
usename       | phatcher
current_query | VACUUM ANALYZE cdm.cdm_reg_customer;
query_start   | 2004-11-09 10:02:32.523146-08


mdc_oz=# select * from pg_locks where pid=16560;
-[ RECORD 1 ]-------------------------
relation    | 7059380
database    | 17145
transaction |
pid         | 16560
mode        | ShareUpdateExclusiveLock
granted     | t
-[ RECORD 2 ]-------------------------
relation    |
database    |
transaction | 28863986
pid         | 16560
mode        | ExclusiveLock
granted     | t
-[ RECORD 3 ]-------------------------
relation    | 7059380
database    | 17145
transaction |
pid         | 16560
mode        | ShareUpdateExclusiveLock
granted     | t

TIA
Patrick Hatcher