This is a discussion on X Row locks causing Lock-waits within the DB2 forums, part of the Database Server Software category; --> DB2 v7.2 (FP7 - DB2 v7.1.0.68) on AIX 5.2.0.0. We're seeing unexpected single row (then commit) insert locking behaviour. ...
| |||||||
| Register | FAQ | Members List | Calendar | Search | Today's Posts | Mark Forums Read |
| ||||
| DB2 v7.2 (FP7 - DB2 v7.1.0.68) on AIX 5.2.0.0. We're seeing unexpected single row (then commit) insert locking behaviour. We're seeing Applications that already hold row-level W locks in lock-wait, waiting to acquire row-level X locks. The lock-waits are behind applications that have row-level X locks on different rows (honestly). Both executing and lock-waiting applications have been granted IX table locks. The table in question has row-level locking only. Can someone advise if this is expected, as I thought two applications could each insert a single row to a table concurrently? Lock snapshot extract as evidence: Application handle = 156 Application ID = 0A0A1401.8906.040713113952 Sequence number = 0001 Application name = java Authorization ID = WEBGFX Application status = Lock-wait Status change time = 07-13-2004 13:27:30.153192 Application code page = 1208 Locks held = 8 Total wait time (ms) = 809358 Subsection waiting for lock = 0 ID of agent holding lock = 132 Application ID holding lock = 0A0A1401.B092.040713131053 Node lock wait occurred on = 0 Lock object type = Row Lock mode = Weak Exclusive (W) Lock mode requested = Exclusive Lock (X) Name of tablespace holding lock = SRCH_DATA_SMALL Schema of table holding lock = GFX Name of table holding lock = SRCH_RSLT_SET Lock wait start timestamp = 07-13-2004 13:27:30.153194 Lock is a result of escalation = NO List Of Locks Lock Object Name = 345109 Node number lock is held at = 0 Object Type = Row Tablespace Name = SRCH_DATA_SMALL Table Schema = GFX Table Name = SRCH_RSLT_SET Mode = X Status = Granted Lock Escalation = NO Lock Object Name = 257 Node number lock is held at = 0 Object Type = Table Tablespace Name = SRCH_DATA_SMALL Table Schema = GFX Table Name = SRCH_RSLT_SET Mode = IX Status = Granted Lock Escalation = NO Application handle = 132 Application ID = 0A0A1401.B092.040713131053 Sequence number = 0001 Application name = java Authorization ID = WEBGFX Application status = UOW Executing Status change time = 07-13-2004 13:38:42.033325 Application code page = 1208 Locks held = 16 Total wait time (ms) = 0 Lock Object Name = 345110 Node number lock is held at = 0 Object Type = Row Tablespace Name = SRCH_DATA_SMALL Table Schema = GFX Table Name = SRCH_RSLT_SET Mode = W Status = Granted Lock Escalation = NO Lock Object Name = 257 Node number lock is held at = 0 Object Type = Table Tablespace Name = SRCH_DATA_SMALL Table Schema = GFX Table Name = SRCH_RSLT_SET Mode = IX Status = Granted Lock Escalation = NO |