|
Problem IT00926
|
Status: Closed |
CONCURRENT LOADS TO THE SAME TABLE MIGHT RESULT IN DEADLOCK |
| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
The deadlock might happen on two concurrent LOADs to the same
table when STATISTICS USE PROFILE is specified at least for one
LOAD. If you monitor the deadlock, such as using EVENT MONITOR,
you can see that one LOAD is holding a Z TableLock on the loaded
table, but waiting for an X RowLock on SYSIBM.SYSTABLES, while
the other LOAD is holding a U RowLock on SYSIBM.SYSTABLES, but
waiting for a Z TableLock on the loaded table. After that, one
LOAD is chosen as victim by DB2 deadlock checking mechanism and
fails with SQL0911N with reason 2, then the other LOAD can
proceed.
The problem is caused by statistics collection during LOAD that
attempts to upgrade current NS RowLock on SYSIBM.SYSTABLES to X
RowLock.
Although the problem might happen on both row-organized and
column-organized tables, concurrent LOADs to the same
column-organized table most likely hit it since STATISTICS USE
PROFILE is the default for column-organized table. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* The users are running two concurrent LOADs. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Cancun Release 10.5.0.4 (also known as Fix *
* Pack 4) or higher. *
**************************************************************** |
| Local Fix: |
Prevent from running concurrent LOAD commands to the same table,
or running concurrent Loads with explicit "STATISTICS NO" . |
| available fix packs: |
DB2 Cancun Release 10.5.0.4 (also known as Fix Pack 4) for Linux, UNIX, and Windows
DB2 Version 10.5 Fix Pack 9 for Linux, UNIX, and Windows
|
| Solution |
Fixed in DB2 Cancun Release 10.5.0.4 (also known as Fix Pack 4) |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 11.04.2014
15.09.2014
14.10.2014 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.5.0.4
|
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