DB2 - Problem description
Problem IT30800 | Status: Closed |
SECOND EXECUTION OF A CACHED CDE QUERY IN DPF ENVIRONMENT MIGHT LEAD TO SEGV (FODC TRAP) OR FODC MEMORY FOR ILLEGAL REQUEST SIZE | |
product: | |
DB2 FOR LUW / DB2FORLUW / B50 - DB2 | |
Problem description: | |
When db2set DB2_CDE_STMTCACHING=YES is set (usually set when DB2_WORKLOAD=SAP is set) In DPF (multi partition setup) a CDE query has to be first executed once, cached, then executed a second time. Depending on the memory layout the second execution can lead to either to a trap (SEGV) or to a Memory FODC due to an illegal memory size request. For the trap the top functions can vary, here are a few examples: ibm_cde::query::Token::decomposeLongTableName() ibm_cde::query::Parser::prepareCachedSTQ() ibm_cde::query::Parser::prepareCachedTree() cdeInterface::initializeData() or ibm_cde::query::SyntaxTree::iterator::goToNext + 0xD8 ibm_cde::query::SyntaxTree::iterator::reset + 0x190 ibm_cde::query::SyntaxTree::iterator::iterator + 0x100 ibm_cde::query::Parser::prepareCachedSTQ + 0x100 ibm_cde::query::Parser::prepareCachedTree + 0x340 ibm_cde::query::Parser::prepareCachedQuery + 0x1F0 cdeInterface::initializeData + 0xB08 The Memory FODC might also have different stacks but the size will be huge: sqloGetMemoryBlockExtended + 0x41C ibm_cde::services::Heap::allocMem + 0x115C std::basic_string::_Copy + 0x8C std::basic_string::basic_string + 0x1E0 ibm_cde::query::Token::decomposeLongTableName + 0xB8 ibm_cde::query::Parser::prepareCachedSTQ + 0x1C4 ibm_cde::query::Parser::prepareCachedTree + 0x340 FUNCTION: DB2 UDB, SQO Memory Management, sqlogmblkEx, probe:1000 MESSAGE : ZRC=0x820F0004=-2112946172=SQLO_MEM_SIZE "Mem Mgt invalid size" DIA8563C An invalid memory size was requested. DATA #4 : Requested size, PD_TYPE_MEM_REQUESTED_SIZE, 8 bytes 648535941969828448 | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * ALL * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Db2 11.5 fp1 or later * **************************************************************** | |
Local Fix: | |
db2set DB2_CDE_STMTCACHING=NO | |
Solution | |
Workaround | |
not known / see Local fix | |
BUG-Tracking | |
forerunner : IJ15638 follow-up : | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 31.10.2019 31.10.2019 31.10.2019 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |