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3155907 - Shared memory causing memory pressure & OOMs on a HANA system


  • Memory pressure and out of memory events are observed on the services for a HANA Tenant database.
  • The trace files show that the typical largest consumer (indexserver) and the other less resource intensive services , use only a portion of the GAL under "AB" & "U" in M_HEAP_MEMORY when compared with the Process Allocation Limit (PAL).
    • indexserver_hostname.3xxx3.rtedump.20220225-000000.0008522.oom.trc

               GLOBAL_ALLOCATION_LIMIT (GAL) = 478.70gb (514007183360b), SHARED_MEMORY = 251.15gb (269677785088b), CODE_SIZE = 3.29gb (3538788352b), OOM_RESERVATION_ALLOCATOR_SIZE = 96.14mb (100810752b)

             PID=8160 (hdbnameserver), PAL=478.83gb (514141401088b), AB=2.64gb (2845290496b), UA=0, U=2.12gb (2279403395b), FSL=0b, FMC=0b
             PID=8420 (hdbcompileserver), PAL=478.83gb (514141401088b), AB=363.79mb (381468672b), UA=0, U=112.05mb (117496888b), FSL=0b, FMC=0b, Blocked=480.91mb (504274944b)
             PID=8423 (hdbpreprocessor), PAL=478.83gb (514141401088b), AB=284.83mb (298676224b), UA=0, U=144.53mb (151559524b), FSL=0b, FMC=0b
             PID=8528 (hdbscriptserver), PAL=478.83gb (514141401088b), AB=875.62mb (918163456b), UA=0, U=677.66mb (710585692b), FSL=0b, FMC=0b
             PID=8525 (hdbscriptserver), PAL=478.83gb (514141401088b), AB=894.23mb (937672704b), UA=0, U=691.59mb (725194260b), FSL=0b, FMC=0b
             PID=8519 (hdbdpserver), PAL=478.83gb (514141401088b), AB=967.69mb (1014706176b), UA=0, U=758.63mb (795490226b), FSL=0b, FMC=0b
             PID=8531 (hdbxsengine), PAL=478.83gb (514141401088b), AB=972.01mb (1019228160b), UA=0, U=771.12mb (808582247b), FSL=0b, FMC=0b
               PID=1234 (hdbindexserver), PAL=478.83gb (514141401088b), AB=214.62gb (230452191232b), UA=0, U=194.29gb (208623357638b), FSL=0b, FMC=0b
             PID=8516 (hdbdocstore), PAL=478.83gb (514141401088b), AB=2.01gb (2167943168b), UA=0, U=1.73gb (1861622187b), FSL=0b, FMC=0b
             PID=19710 (hdbwebdispatcher), PAL=478.83gb (514141401088b), AB=401.16mb (420646912b), UA=0, U=313.40mb (328633396b), FSL=0b, FMC=0b
               PID=19707 (hdbdiserver), PAL=478.83gb (514141401088b), AB=202mb (211816448b), UA=0, U=96.20mb (100884174b), FSL=0b, FMC=0b

             Total allocated memory= 478.59gb (513884377088b)
             Total used memory     = 456.08gb (489719383067b)
             Sum AB                = 240667803648
             Sum Used              = 216502809627
               Heap memory fragmentation: 4

             Top "M_HEAP_MEMORY" allocators (component, name, size). Ordered descending by exclusive_size_in_use.
              1: Row Store Tables:                           Pool/RowStoreTables/CpbTree                                          63.47gb (68155880784b)
              2: Column Store Tables:                        Pool/ColumnStore/Main/Dictionary/RoDict                              53.57gb (57521045444b) (256mb (268435456b) precharged, 2mb (2097152b) in preparation)
                3: System:                                     Pool/PersistenceManager/PersistentSpace/RowStoreLPA                  13.69gb (14702084928b)          ............ 
  • The rest of the allocated memory is consumed by the "SHARED_MEMORY" component.
    • GLOBAL_ALLOCATION_LIMIT (GAL) = 478.70gb (514007183360b), SHARED_MEMORY = 251.15gb (269677785088b), CODE_SIZE = 3.29gb (3538788352b), OOM_RESERVATION_ALLOCATOR_SIZE = 96.14mb (100810752b) 

                Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.



  • SAP HANA 2.0, platform edition
  • SAP HANA 1.0, platform edition


SAP HANA 1.0, platform edition ; SAP HANA, platform edition 2.0


SHARED_MEMORY, OOM, Resman Shrink, Allocation Failed, memory allocation failed , KBA , HAN-DB-ENG , SAP HANA DB Engines , Problem

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