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3247551 - High memory usage in allocator Pool/RowStoreTables/Version

Symptom

From time to time HANA DB system is unresponsive for some seconds.

Sometimes, in a HANA System Replication environment, unresponsive symptom will lead to "HANA_CALL timed out" error in HANA traces. 

Looking into indexserver trace file, you can find error message about "un-collected versions" and memory shrink information as follows: 
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[368913]{-1}[-1/-1] 2022-07-02 05:33:04.536238 e KernelSentinel   KernelSentinelJob.cpp(01483) : There are too many un-collected versions on table 'SAPABAP.BKPF' (TABLE_OID = BKPF, NUM_VERSIONS = 12098450, MIN_READ_TIMESTAMP = 32248024052).
The transaction possibly blocks the garbage collection:
 CONNECTION_ID = 324506, HOST = hostname:30003, VOLUME_ID = 3,
 TRANSACTION_ID = "582", TRANSACTION_TYPE = "USER TRANSACTION",
 PRIMARY_TRANSACTION_ID = "-1", PRIMARY_TRANSACTION_TYPE = "",
 UPDATE_TRANSACTION_ID = "0", MIN_MVCC_SNAPSHOT_TIMESTAMP = 32248024052,
 TRANSACTION TOTAL EXECUTED TIME = 0 sec.
The cursor possibly blocks the garbage collection: 
 CONNECTION_ID = 324506, CONNECTION_STATUS = RUNNING, HOST = hostname : 30003, IDLE_TIME = 216 sec,
 STATEMENT_STATUS = SUSPENDED, STATEMENT_LIFE_TIME = 852772 sec, ISOLATION_LEVEL = READ COMMITTED.
...
IPMM short info:
...
Top "M_HEAP_MEMORY" allocators (component, name, size). Ordered descending by exclusive_size_in_use.
 1: Row Store Tables:                           Pool/RowStoreTables/Version                                             1.50tb (1658229374984b)
 2: System:                                     Pool/RowEngine/RowTableManager/MVCCManager/MVCCAllocator                457.38gb (491116833448b)
...
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Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.


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Environment

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

Product

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

Keywords

SAP HANA, Pool/RowStoreTables/Version, garbage collection, versions, version, row store, idle_cursor_lifetime, idle_connection_timeout, write_transaction_lifetime,garbage collection blockage, indexserver.ini, un-collected versions , KBA , HAN-DB , SAP HANA Database , Problem

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