DB2 - Problem description
Problem IT33863 | Status: Closed |
PURESCALE MEMBER MIGHT HANG WAITING FOR SQLO_LT_SQLB_BPD__BPDLATCH_SX WHILE IN SQLBGBUPGRADELATCHFROMSHAREDURINGWAR | |
product: | |
DB2 FOR LUW / DB2FORLUW / B50 - DB2 | |
Problem description: | |
Under certain timing conditions a hang/deadlatch can occur after an agent has sent modified pages to the Group Buffer Pool (GBP). An agent (A) will be holding one or more page latches (SQLO_LT_SQLB_BPD__bpdLatch_SX) in shared (S) mode, and attempting to upgrade a page latch to exclusive (X) mode in function sqlbgbUpgradeLatchFromShareDuringWAR. This agent will have a stack similar to the following: getConflictComplex getConflict sqlbgbUpgradeLatchFromShareDuringWAR sqlbgbWARM_PostProcessing sqlbgbWARM Meanwhile, another agent (B) will be holding (in S or X mode) the page latch agent A is attempting to latch. At the same time agent B will be attempting to latch in X mode one of the page latches that is held in S mode by agent A. Agent B might have a stack similar, but not limited to, the following: getConflictComplex getConflict sqlbFindPageInBPOrSim sqlbfix | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * all * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to db2_v115m5fp0 or later * **************************************************************** | |
Local Fix: | |
The hang/deadlatch is contained within a member. Killing the member and allowing it to recover will resolve the hang. A workaround to prevent the hang is to do the following: db2set DB2_HIGH_CONCURRENCY_WAR=OFF. Each member would have to have db2stop and db2start run for this to take effect. Note that this will have a negative performance impact for heavy insert, update, or delete workloads. | |
Solution | |
Workaround | |
not known / see Local fix | |
BUG-Tracking | |
forerunner : IT33836 follow-up : | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 11.08.2020 19.11.2020 19.11.2020 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |