Hi All,

Just to share the result for simple queries performed on in memory Column Store table with SAP Dynamic Tiering Extende table on disk storage.

Platform:

HANA DB Version – HANA SPS09 revision 91

SAP Dynamic Tiering – SAP IQ 16 SP9

Scenario:

a) RLV (delta) enable on Extended Storage

b) Number of entries for CS table and ES table is identical as data in ES table was copied from CS table.

-> Column Store

-> Extended Storage

Simple queries performed and its results:

From the result above, we see that complete search (select *) is faster for Extended Storage and queries with selection process is much faster on CS.

This probably Extended Storage is ROW-BASED storage as per for visualize plan below? Remote Row Scan is used all queries on Extended Storage table.

Trying to figure out more how exactly Dynamic Tiering works for its Extended Table especially during data insert/import, unfortunately, couldn’t dig more as there’s no useful info written on esserver trace, indexserver trace, etc, and also log files in SAP IQ directories.

What I can see is just the size growing on file system, HANA admin cockpit and view M_ES_*

Input for this missing technical piece on SAP Dynamic Tiering Extended Table is greatly welcomed and appreciated.

Thanks,
Nicholas Chang

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2 Comments

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  1. Lars Breddemann

    As mentioned in your other blog post, ESS is not row based – but the communication between indexserver and ES server is. That’s why you see a “row scan” operation.

    It doesn’t tell you exactly what’s happening in the ES server, but rather shows you how the indexserver “sees” the operation.

    Compare that to the SDA table acesses – it’s pretty similar in this regard.

    – Lars

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