|
Problem IT18835
|
Status: Closed |
LONG QUERY RUNTIME WITH INTRA-PARALLEL AND COMPRESSED INDEXES |
| product: |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 |
| Problem description: |
SQL queries on large tables using compressed indexes may show
long runtimes, when the used index has a low cardinality and the
query degree is larger than 1.
In a db2 trace you can see that most time is spent in function
sqliSkipRangeForward
One agent stack shows:
sqliRL_CountRidsFromCompressedPage
sqliSkipRangeForward
sqliFindEndOfRange
sqliGetNxtRng
sqliGetNxtRng
sqliGetNxtRng
sqldIndexFetch
sqldRowFetch
sqldRowFetch
sqlritaSimplePerm
sqlriSectInvoke
sqlrr_subagent_router
Other sub agents are in a latch conflict waiting for latch
SQLO_LT_SQLI_PARSCAN__parScanLatch.
Stacks may show:
thread_wait
getConflictComplex
sqliGetNxtRng
sqldIndexFetch
sqldRowFetch
sqldRowFetch
sqlritaSimplePerm
sqlriSectInvoke
sqlrr_subagent_router |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Db2 10.5 Fix Pack 9 or higher *
**************************************************************** |
| Local Fix: |
Either don´t use a compressed index or set query degree to 1 for
the affected query or globally (DFT_DEGREE=1). |
| Solution |
First fixed in Db2 10.5 Fix Pack 9 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 16.01.2017
29.09.2017
29.09.2017 |
| Problem solved at the following versions (IBM BugInfos) |
9.0.
|
| Problem solved according to the fixlist(s) of the following version(s) |
