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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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