DB2 - Problembeschreibung
Problem IC93299 | Status: Geschlossen |
STMM UNNECESSARILY DECREASES CONFIGURATION WHEN 0 BENEFIT DETECTED | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
Problembeschreibung: | |
If the STMM tuner detects a "0" benefit/cost for all STMM-tuned areas, and only a single database is being tuned, the free memory target will switch from the minimum to the maximum value in the free memory target range. (eg. from 1% to 10% of RAM). This may trigger a corresponding decrease in the STMM-tuned configuration (eg. large decrease in bufferpools). The assumption is that the database is idle, but often this is a very temporary condition, or is a result of limiting STMM tuning to areas which often don't have a continuous high need for memory (eg. locklist, package cache). The magnitude of the switch is large and can disrupt performance. Instead, the minimum free target should be maintained (the STMM tuner will still react to constrained memory conditions as part of normal tuning). Note this issue applies only when database_memory is automatic and stmm tuning is enabled. The STMM logs will contain an entry similar to the following : FUNCTION: DB2 UDB, Self tuning memory manager, stmmGetDBMemDataAutomatic, probe:3867 DATA #1 : String, 409 bytes Configured memory on the system: 83886080 Memory currently available on the system: 9763323 Configured memory on the partition: 67108864 Memory currently available on the partition: 765120 Set's configured size: 64637056 Overflow left: 4693216 Uncommited size: 3777200 Target consumer size: 55963646 Current consumer size: 59943840 Max growth: 0 Average benefit: 0 Partition benefit: DB: SAMPLE Benefit: 0 or Global benefit: DB: SAMPLE Benefit: 0 In this case, the Average benefit is 0 for the Sample database. It is also the only database competing for memory, so is also the highest benefit database - showing up in the line with Partition or Global benefit. The target memory consumption will be much lower as compared with normal STMM tuning when this condition is detected. | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * Systems using self-tuning (STMM) of database_memory * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 Version 9.7 Fix pack 9 * **************************************************************** | |
Local-Fix: | |
use a fixed database_memory setting | |
verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows | |
Lösung | |
Problem first fixed in DB2 Version 9.7 Fix pack 9 | |
Workaround | |
See Local Fix | |
Bug-Verfolgung | |
Vorgänger : APAR is sysrouted TO one or more of the following: IC93472 IC93475 IC95488 Nachfolger : | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 21.06.2013 26.12.2013 26.12.2013 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7.FP9 | |
Problem behoben lt. FixList in der Version | |
9.7.0.9 | |
9.7.0.9 |