DB2 - Problem description
Problem IT35021 | Status: Closed |
High CPU and decreased performance with high concurrency of index creation (on TEMP TABLES) | |
product: | |
DB2 FOR LUW / DB2FORLUW / B10 - DB2 | |
Problem description: | |
Db2 by default uses the compression for indexes on created/declared temporary tables (CGTTs/DGTTs) and this behavior cannot be explicitly disabled, that is, there is no possibility to use "COMPRESS NO" keyword. Index compression feature availability is predicated on Db2 license type, which is checked during index creation and requires a serialization via a latch (mutex). If indexes are created with a very high concurrency the performance of that operation can be affected and CPU usage on the system will increase. This typically happens with a scenarios involving indexes on declared/created temporary tables that have indexes defined. A backtrace of Db2 engine threads (EDUs) collected during the issue with a debugger/profiler or "db2pd -stack" will show a call stack with the following functions near the top: ossLockGetConflict NetlsRequestLicense LicGetAccessKey sqllcRequestAccess sqloSqlcRequestAccess sqloLicRequestAccess sqldIndexType sqldIndexCreate sqlrlRecreateSingleIndex sqlrlRecreateIndexObject sqlrlRecreateIndexes This APAR will address the behavior by reducing the frequency of license type checks. | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * upgrade to 11.1.4.6 or higher * **************************************************************** | |
Local Fix: | |
Solution | |
Workaround | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * upgrade to 11.1.4.6 or higher * **************************************************************** | |
Comment | |
upgrade to 11.1.4.6 or higher | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 23.11.2020 12.03.2021 12.03.2021 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |