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2975817 - Locks caused by enabled Data Statistics Adviser Cache

Symptom

Performance degradation on database queries that were running fine before.
Threads are in state "IntentLock Enter" or "ExclusiveLock Enter" with lock name "TREXCache_CacheInstance".

Runtimedump shows that threads are waiting for a thread with call stack like:

Synchronization::ReadWriteLock::timedWaitLockSharedLL
Synchronization::ReadWriteLock::lockIntent
Cache::CacheInstance<Cache::Key<DataStatistics::DataStatisticsAdviserCache::Key>, Cache::Value<DataStatistics::DataStatisticsAdviserCache::Value>, Cache::SingleValueVersion>::lookupInternal
Cache::CacheInstance<Cache::Key<DataStatistics::DataStatisticsAdviserCache::Key>, Cache::Value<DataStatistics::DataStatisticsAdviserCache::Value>, Cache::SingleValueVersion>::lookup
DataStatistics::DataStatisticsAdviserCache::lookup
DataStatistics::DataStatisticsAdviserCache::createNewEntry
DataStatistics::DataStatisticsAdviserCache::createNewEntries
DataStatistics::DataStatisticsAdviserCache::createNewEntries
DataStatistics::CS_StatisticsImpl::getColumnsStats
DataStatistics::DS::getColumnsStats
DataStatistics::DS::getColumnStat
DataStatistics::StatisticsGovernor::getDataStatisticsPartitionStatistics
DataStatistics::StatisticsGovernor::addMissingAndNotFoundAdviserEntries
DataStatistics::QueryAndPartitionInfo::querySimpleDataStatisticsAndPrunePartitions
DataStatistics::StatisticsGovernor::dataStatisticsPartitionPruning


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Environment

SAP Hana Platform Edition 1.0
SAP Hana Platform Edition 2.0

Product

SAP HANA, platform edition all versions

Keywords

KBA , HAN-DB-PERF , SAP HANA Database Performance , Problem

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