2522867 - query non-fatal error at s_index::NullCount followed by server abort at hs_dpGroup::hs_dpGroup - SAP IQ

• SAP IQ multiplex environment,  random and infrequent query failures with Non Fatal error at s_index.cxx with this stack

  s_index::NullCount()
  dfe_BaseColumn::GatherMetaData()
  dfe_BaseColumn::GetDataProjectionLength()
  opt_TableNode::GatherWidthMetaData
  opt_QueryTree::GatherAllWidthMetaData
  opt_QueryTree::PreProcessQueryTree()
  opt_Select::PrepareTops
  opt_QueryExp::PrepareTops
  opt_Select::PrepareTops
  opt_QueryExp::PrepareTops
  opt_QueryExp::PrepareAndExecTops()
  opt_Driver::OptimizeQueryExp
  dfo_Root*opt_Driver::GenerateTree

• This non fatal sometimes lead to a server abort and st_server.cxx  with this stack

  hs_dpGroup::hs_dpGroup
  s_indexGroup*hs_dp::OpenGroup
  dfe_VirtualColumn::FindDistinctCountBySort
  dfe_VirtualColumn::GatherBasicMetaData()
  dfe_VirtualColumn::GetDistinctCount()
  dfp::EstimateLocalSelectivityMain(int)
  dfp::UsefullnessCompare
  hos_heapsort_ptr_arr_obj<hos_Object,ComparePtrAdapter<int(*)
  hos_vector_noerror::Sort
  opt_QueryNode::DropLocalRedundantEQPreds()
  opt_QueryNode::RecursivelyDropRedundantEQPreds()
  opt_QueryTree::OptimizeJoinTree
  opt_QueryTree::ProcessQueryTree()
  dfo*opt_Select::GenerateDFOs

• running a sp_iqcheckdb  dbcc consistency checker to verify objects involved shows no corruption issues
  
  
• issue seen with select count union all type queries
  
  
• issue not easily reproducible and resubmission of failing query works

• SAP IQ 16 SP11 multiplex
  
  
• So far only reported on patch level PL05 and below on Solaris, however it is not expected to be platform dependant

sybase, crash, CR810284, CR#810284, 810284, 'gather metadata', 'non fatal', nonfatal, buffman, sporadic, server, mpx, writer, node, , KBA , BC-SYB-IQ , Sybase IQ , Problem