DB2 FOR LUW / DB2FORLUW / A10 - DB2

The Apar improves standby replay performance in following 
aspects: 
 
1. Transaction Hash Table to speedup TEntry lookup time 
 
2. Log Record Descriptor Area Pre-allocation 
- Before each time when redo master tries to create a sync log 
record, we need to obtain a QEntry from the QEntry free list. 
After that, we have to dynamically allocate the descriptor area. 
 
3. Redo Workers Qcblatch Changes 
- Redo workers take the Qcblatch conditionally and automatically 
yields if no work available. This reduces Qcblatch contention. 
 
4. Page Cleaning Rate Reduction Reg Var - 
DB2_LOG_REPLAY_PAGE_CLEANING_REDUCTION_FACTOR 
Example: db2set DB2_LOG_REPLAY_PAGE_CLEANING_REDUCTION_FACTOR=2 
This provides a way to allow different page cleaning policy to 
be used during database recovery vs normal runtime. 
 
We also introduce new performance metrics to measure redo master 
and determine replay bottleneck. 
Customer could issue "db2pd -dpsprcb 1 -db <dbname>" to collect 
following data. 
1. Main Performance Counters 
- redomTotalWaitForShredderTime 
- redomTotalWaitForFreeQEntryTime 
- redomTotalHandleLogRecPoolsTime 
- redomTotalGetDBCBForTransactionTime 
- redomTotalAsyncFlushBPTime 
- redomTotalGetTEntryTime 
- redomTotalDbBlockingWaitForRedowFinishTime 
- redomTotalTbspBlockingRecPulishingTime 
- redomTotalMultiPageBlockingRecPublishingTime 
- redomTotalPageBlockingRecPublishingTime 
- redomTotalDpsQPublishingTime 
- redomTotalDpsQProcessingTime 
 
2. Sub-counters (breakdown of some main counters) 
- redomTotalTbspBlockingRecPulishingTime_sub1 
- redomTotalMultipageBlockingRecPublishingTime_sub1 
- redomTotalQsPublishingTime 
- redomTotalGetWaitOthersTime 
- redomTotalCreateQEntryTime 
- redomTotalCreateQEntryTime_sub1

**************************************************************** 
* USERS AFFECTED:                                              * 
* ALL                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 10.1 Fix Pack 6                               * 
****************************************************************

First fixed in DB2 10.1 Fix Pack 6

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

30.11.2016
02.03.2017
02.03.2017