3230934 - High CPU usage of FDA write query on SAP HANA 2.0 SPS06

• After upgrading to SAP HANA 2.0 SPS06 some queries are using high CPU.
• Kernel profiler trace shows that most of the CPU is used in call "void AttributeEngine::fnBwProcessDocidsForGet2".
  E.g:

• Thread samples show that the most dominant query uses FDA WRITE, e.g.:
  SELECT /* FDA WRITE */ DISTINCT  "BKPF" . "MANDT"...
• Script "HANA_Threads_Callstacks_History" filtered to the timeframe of the issue and affected query shows that most threads are in call "void AttributeEngine::fnBwProcessDocidsForGet2"
  E.g.:
  ---------------------------------------------------------------------------------------------------------
  |STATEMENT_HASH  |COUNT|CALL_1                                                                          |
  ---------------------------------------------------------------------------------------------------------
  |<statement_hash>|  843|void AttributeEngine::fnBwProcessDocidsForGet2<AttributeEngine::PrefixMemoryDocu|
  |<statement_hash>|  448|void AttributeEngine::fnBwProcessDocidsForGet2<AttributeEngine::RleMemoryDocumen|
  |<statement_hash>|   65|void AttributeEngine::fnBwProcessDocidsForGet2<AttributeEngine::PrefixMemoryDocu|
  |<statement_hash>|   65|void AttributeEngine::fnBwProcessDocidsForGet2<AttributeEngine::IndirectMemoryDo|
  |<statement_hash>|   57|syscall                                                                         |
  ---------------------------------------------------------------------------------------------------------
• Example of full call stack:
  void AttributeEngine::fnBwProcessDocidsForGet2
  int AttributeEngine::fnBwGetAggregateValueIds
  AttributeEngine::SinglePagedSpBase
  OlapEngine::Parallel::OlapAttributeApi::bwGetAggregateValueIds
  OlapEngine::Parallel::DimensionReader
  OlapEngine::Parallel::WorkerJob::run
  TRexUtils::Parallel::JobBase::runEx
  TRexUtils::Parallel::JobBase::run
  Execution::JobObjectImpl::run
  Execution::JobWorker::runJob
  Execution::JobWorker::run
  Execution::Thread::staticMainImp
  Execution::pthreadFunctionWrapper
  <no symbol>

SAP S/4HANA with SAP HANA 2.0 SPS06

"for all entries", NO_GROUPING_SIMPLIFICATION, CS_ITAB_IN_SUBQUERY, prefer_cs_itab_in_subquery_for_param_itab , KBA , HAN-DB-PERF , SAP HANA Database Performance , BC-DB-DBI , DB Independent Database Interface , Problem