2568019 - The first load data job performs poorly after upgrading to IQ 16.0 from IQ 15.4

1. After upgrade to SAP IQ 16 from IQ 15.4, the first load table into some large table with many HG indexes perform poorly. The load performance was also poor even when loading an empty file.
2. Once the initial loading completed, the subsequent load jobs against those tables worked well.
3. After removing of the HG indexes before running the initial data loading, the performance is normal.
4. According to the query plan, the root node shows that there were big time gap between cursor creation time and end of DFE generation
   =============================================
   Time of Cursor Creation 2017-11-20 16:11:19.192404
   End of DFE Generation 2017-11-21 03:17:34.901687
   ...
   Time of Complete Return 2017-11-21 03:17:35.851734
   Elapsed Condition time 0:00:00.000000
   Working time 11:06:16.613421
   Elapsed time 11:06:16.659330
   =============================================
   
   
5. The thread stack for the load table command is as below.

----------------- lwp# 133 / thread# 133 --------------------
_pread (....................
__1cMhos_pi_pread6FnGhos_fd_pvIl_i_ (....................
__1cJhos_svbioFRead26MXpviri2pXpnSs_bufman_errorInfo__i_ (....................
__1cJhos_mvbioFRead26MXpviri2pXpnSs_bufman_errorInfo__i_ (....................
__1cFs_bufQReadBufAndVerify6MpnSs_bufman_errorInfo_pnRs_diskblockheader_XIIihXIipnTs_bufmanCallerStats__v_ (....................
__1cFs_bufERead6MpnSs_bufman_errorInfo_XIihXIIpknKs_blockmap_pnTs_bufmanCallerStats__v_ (....................
__1cOs_bufpartitionEFind6MpnSs_bufman_errorInfo_pnWs_connectionCacheStats_pnHhos_bio_XXXIIiIIhpnKs_blockmap_nIs_bufmanIs_paging_n0FLs_dirtyMode_IpnTs_bufmanCallerStats__pnFs_buf__ (....................
__1cKs_blockmapEFind6MXhipnTs_bufmanCallerStats__pnFs_buf__ (....................
__1cQs_pageListCursorMPositionPage6MX_pv_ (....................
__1cUs_garrayReadCursorV2PResettoNextPage6M_i_ (....................
__1cOhs_ohcidentitySTryUpgradeIdentity6MpnRhs_ohcIdentity_15_pnGhs_ohc_pnKhs_context_nKs_openmode__i_ (....................
__1cGhs_ohc2t5B6MpnLdb_IndexDef_nKs_openmode_pknFhs_dp__v_ (....................
__1cLdb_IndexDefSOpenSIndexWithLock6MI_pnHs_index__ (....................
__1cLdb_IndexDefKOpenSIndex6MI_pnHs_index__ (....................
__1cLdb_IndexDefOOpenSIdxInsert6MI_pnNs_indexInsert__ (....................
__1cIdf_TableLAddIndexDef6MpnLdb_IndexDef_i_v_ (....................
__1cNopt_LoadTableMGenerateDFEs6MpnHdf_Heap_pnMopt_QdDueryExp__v_ (....................
__1cKopt_DriverMGenerateTree6FpnJQdDueryNode_pnJst_cursor_pknLa_statement_pnHUITable_pnHUIIndex_pnEs_bm_pIppnTdb_RebuildIndexInfo_ipnHa_table_pnShos_vector_noerror_pnIhs_store_ipnWdb_IQdDParallelIndexInfo_pnQrv_MergeCmdState__pnIdfo_Root (....................
__1cMdb_LoadTableHExecute6M_v_ (....................

SAP IQ 16.0 SP11 PL11

 SAP IQ, IQ, load, load table, initial loading, first data loading, migration, IQ 16.0, performance, __1cMhos_pi_pread6FnGhos_fd_pvIl_i_, __1cJhos_svbioFRead26MXpviri2pXpnSs_bufman_errorInfo__i_, __1cJhos_mvbioFRead26MXpviri2pXpnSs_bufman_errorInfo__i_, CR 811985, CR#811985 , KBA , BC-SYB-IQ , Sybase IQ , Problem