DB2 - Problembeschreibung
Problem IC75870 | Status: Geschlossen |
GLOBAL SNAPSHOTS MAY CONSUME A LARGE AMOUNT OF FCM BUFFERS | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 | |
Problembeschreibung: | |
In a multipartition environment, a large amount of FCM buffers can be consumed by large global snapshots. One example of such large global snapshots is, "db2 get snapshot for locks on <dbname> global" when there are many locks currently being held in the database. db2pd -fcm hwm output would show a single application consuming a lot of buffers | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * DPF environments * **************************************************************** * PROBLEM DESCRIPTION: * * Global snapshots collect monitoring information from all * * database partitions and aggregate the result at the * * coordinating partition. FCM buffers are required to send and * * receive the monitoring information. The coordinating * * partition can consume a large number of FCM buffers * * equivalent to the size of the entire snapshot result. If * * the database manager runs out of FCM buffers then node * * failure is invoked to remedy the situation. This could lead * * to applications receiving -1229 errors or losing connection * * to the database. * * * * Note that monitoring tools like db2top issue global * * snapshots. * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 v9.5 FP8 or later and enable flow control. * **************************************************************** | |
Local-Fix: | |
The work around of setting DB2_MAX_GLOBAL_SNAPSHOT_SIZE should help to prevent a single snapshot from consuming all FCM buffers. Multiple concurrent large snapshots would still be a problem though. | |
verfügbare FixPacks: | |
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows | |
Lösung | |
As of DB2 v9.5 fp8, the fix for this APAR can be enabled by using the following registry variable setting: db2set DB2_SYSTEM_MONITOR_SETTINGS=ENABLE_FLOW_CONTROL:TRUE This is a dynamic setting which means the instance does not have to be restarted to pick up the registry variable setting. With flow control enabled, global snapshots will not consume a large number of FCM buffers. | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 18.04.2011 27.06.2011 27.06.2011 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.5.FP8, 9.5.FP8 | |
Problem behoben lt. FixList in der Version | |
9.5.0.8 |