DB2 FOR LUW / DB2FORLUW / A50 - DB2

Under rare runtime condition, Db2 might not reuse the dynamic
SQL variation across multiple connection, which will result in:
- multiple variations of the same dynamic SQL kept in package
cache
- an increased time spent compiling queries
- latch waits on SQLO_LT_sqlrlc_anchor_common__anchor_latch,
which is obtained during compilation


Problem is specific to Db2 version 10.5 Fix Pack 9 and 10 (i.e.
it did not exist in FP8 and older) can be diagnosed by reviewing
"db2pd -dynamic" output, were we would see high number of
variations (NumVar) for the same statement (AnchID, StmtUID
pair), e.g.:

Dynamic SQL Statements:
AnchID StmtUID    NumEnv     NumVar     NumRef     NumExe
Text
851    1          1          19058      13867834   13867834


Dynamic SQL Variations:
AnchID StmtUID   EnvID     VarID     NumRef   Typ
851    1         20        1520360   1        6
851    1         20        1520359   1        6
851    1         20        1520358   1        6
851    1         20        1520357   1        6
851    1         20        1520356   1        6

Setting an internal access plan manager (APM) variable may help
resolve the problem:
$ db2set APM_THROTTLE=70
(instance restart required)

not known / see Local fix

This APAR is a duplicate of IT27830

forerunner  : 
follow-up : IT27829 

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

21.01.2019
20.04.2020
20.04.2020