|
Problem IT05716
|
Status: Closed |
UNDER RARE CIRCUMSTANCES, QUERY IN DPF ENVIRONMENT MIGHT HANG IN MERGING DIRECTED TABLE QUEUE (MDTQ) |
| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
In partitioned partitioned environment (or with
INTRA_PARALELL=YES), query involving merging directed table
queue (MDTQ) might hang due to specific data layout (skew).
Receiving subsections will wait for any node in state:
Subsection status = Waiting
to receive on tablequeue
Node for which waiting on tablequeue = Any node
Tablequeue ID on which agent is waiting =
<id_of_mdtq>
and stack:
sqloWaitEDUWaitPost
sqkfChannel::WaitRecvReady
sqkfChannel::ReceiveAnyBuffer
sqlktrcv
sqlkt_unpack_tuple
whilst senders will await specific specific partition, e.g
Subsection status = Waiting
to send on tablequeue
Node for which waiting on tablequeue = 10
Tablequeue ID on which agent is waiting =
<id_of_mdtq>
and stack:
sqloWaitEDUWaitPost
sqkfChannel::WaitSendReady
sqkfChannel::isAnySendReady
sqlkqsnd
sqlktsnd
sqlkt_pack_tuple
sqlktins
sqlritqb
sqlriSectInvoke |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* DPF/INTRA_PARALELL *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 10.5 Fix Pack 7 or higher. *
**************************************************************** |
| Local Fix: |
In most situations, hang can be avoided by:
DB2_SORT_AFTER_TQ=YES
on global (db2set) or statement level (profile):
<REGISTRY><OPTION NAME='DB2_SORT_AFTER_TQ'
VALUE='YES'/></REGISTRY> |
| Solution |
Fixed in DB2 Version 10.5 Fix Pack 7. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 21.11.2014
28.01.2016
28.01.2016 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.5.0.7
|
 |
