DB2 - Problem description
Problem IT36753 | Status: Closed |
IN SOME RARE CASES, A SORT ON A COLUMNAR TABLE CAN HANG | |
product: | |
DB2 FOR LUW / DB2FORLUW / B50 - DB2 | |
Problem description: | |
In some rare cases a SORT query on a columnar table can hang. The query does not have to be very complex. Even a straightforward sort query like INSERT .. SELECT FROM ORDER BY col can hang. The stacks would be: Threads doing the SORT: sqloPostEDUWaitPost + 0x0098 ibm_cde::services::EventWaitPost::post(unsigned int) + 0x0080 ibm_cde::query::SortEvaluator::processInputsSynchronously() + 0x0894 ibm_cde::query::Evaluator::evaluate(bool, bool, ibm_cde::query::Evaluator::EvaluatorRestartState&, ibm_cde::query::OptPredicateTracker*) + 0x059c ibm_cde::query::EvaluationRoutine::evaluate(unsigned int, sql_static_data*) + 0x02f4 ibm_cde::query::Scheduler::evaluateChain(ibm_cde::query::Evaluat ionRoutine*, unsigned long&, unsigned int) + 0x04d8 ibm_cde::query::Scheduler::runWorkerThread(void*, int*) + 0x0580 ibm_cde::query::cdeEntryPointImpl(sqeAgent*, void*, void*) + 0x0088 cdeInterface::startCdeSubagent(sqeAgent*) + 0x00d4 sqlriInvokeCde(sqlrr_cb*) + 0x0050 or sqloPostEDUWaitPost + 0x0098 ibm_cde::services::EventWaitPost::post(unsigned int) + 0x0080 ibm_cde::query::SortEvaluator::processInputsSynchronously() + 0x0894 ibm_cde::query::Evaluator::evaluate(bool, bool, ibm_cde::query::Evaluator::EvaluatorRestartState&, ibm_cde::query::OptPredicateTracker*) + 0x059c ibm_cde::query::EvaluationRoutine::evaluate(unsigned int, sql_static_data*) + 0x02f4 ibm_cde::query::Scheduler::evaluateChain(ibm_cde::query::Evaluat ionRoutine*, unsigned long&, unsigned int) + 0x04d8 ibm_cde::query::Scheduler::runWorkerThread(void*, int*) + 0x0580 ibm_cde::query::cdeEntryPointImpl(sqeAgent*, void*, void*) + 0x0088 cdeInterface::startCdeSubagent(sqeAgent*) + 0x00d4 sqlriInvokeCde(sqlrr_cb*) + 0x0050 The consumer side will be in this stack: semtimedop + 0x0038 ibm_cde::services::EventWaitPost::wait(int, unsigned int*) + 0x0ac0 ibm_cde::query::StreamingResultIterator::consumerEventWait(unsig ned int, ibm_cde::services::GeneralTimer&, ibm_cde::services::DB2MonitorInterface&, ibm_cde::services::ScopedMutex&) + 0x024c ibm_cde::query::StreamingResultIterator::getNextVectors(std::vec tor&, ibm_cde::query::WorkunitMemStats*, bool, SQLO_MEM_POOL*) + 0x0f68 ibm_cde::query::LoadNestedQueryEvaluator::processInputsSynchrono usly() + 0x13ac ibm_cde::query::Evaluator::evaluate(bool, bool, ibm_cde::query::Evaluator::EvaluatorRestartState&, ibm_cde::query::OptPredicateTracker*) + 0x059c ibm_cde::query::EvaluationRoutine::evaluate(unsigned int, sql_static_data*) + 0x02f4 ibm_cde::query::Scheduler::evaluateChain(ibm_cde::query::Evaluat ionRoutine*, unsigned long&, unsigned int) + 0x01c8 ibm_cde::query::Scheduler::runWorkerThread(void*, int*) + 0x0580 ibm_cde::query::cdeEntryPointImpl(sqeAgent*, void*, void*) + 0x0088 The symptom is that this SORT will never come out of this state. | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * Columnar SORT * **************************************************************** * PROBLEM DESCRIPTION: * * Please See Error Description and install this fix. * **************************************************************** * RECOMMENDATION: * * Upgrade to 11.5.6 or later * **************************************************************** | |
Local Fix: | |
Retry the SORT command. | |
Solution | |
Workaround | |
**************************************************************** * USERS AFFECTED: * * Columnar SORT * **************************************************************** * PROBLEM DESCRIPTION: * * Please See Error Description and install this fix. * **************************************************************** * RECOMMENDATION: * * Upgrade to 11.5.6 or later * **************************************************************** | |
Comment | |
Upgrade to 11.5.6 or later | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 30.04.2021 16.06.2021 21.06.2021 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |