DB2 - Problem description
Problem IC95391 | Status: Closed |
On DPF, a hang can occur if an interrupt is received during the execution of a query that contains a correlated sub query. | |
product: | |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 | |
Problem description: | |
For this problem to happen, ALL of the following conditions need to be true: 1) An interrupt (or any possible error) is received with a specific timing during the execution of a query. 2) The query in question has the following characteristics: a) There is a correlated subquery, where the access plan of the subquery contains a union operation that itself exists on the probe (left) side of hash join. b) There is a hash join inside one of the union legs. As well, this problem is much more likely to happen in DPF. While it's technically possible that the problem could happen in a non-dpf environment, it doesn't seem likely there. Further, there may also be other unexpected symptoms if, rather than item b) above, it is some other operation inside the union leg. In the case where this was discovered, a db2trc will reveal a hash join looping infinitely like this: 1 sqlrihsjn entry [eduid 135 eduname db2agent] 2 sqlrihsjn exit 3 sqlrihsjn entry [eduid 135 eduname db2agent] 4 sqlrihsjn exit 5 sqlrihsjn entry [eduid 135 eduname db2agent] 6 sqlrihsjn exit 7 sqlrihsjn entry [eduid 135 eduname db2agent] 8 sqlrihsjn exit 9 sqlrihsjn entry [eduid 135 eduname db2agent] 10 sqlrihsjn exit 11 sqlrihsjn entry [eduid 135 eduname db2agent] 12 sqlrihsjn exit 13 sqlrihsjn entry [eduid 135 eduname db2agent] 14 sqlrihsjn exit ...<snip...repeating...> | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * ALL * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 Version 10.5 Fix Pack 3. * **************************************************************** | |
Local Fix: | |
It may be possible to rewrite the query so to avoid the correlation subquery. | |
available fix packs: | |
DB2 Version 10.5 Fix Pack 3 for Linux, UNIX, and Windows | |
Solution | |
First fixed in DB2 Version 10.5 Fix Pack 3. | |
Workaround | |
not known / see Local fix | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 27.08.2013 27.02.2014 27.02.2014 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) | |
10.5.0.3 | |
10.5.0.3 |