Data Virtualization optimisation

[MattRogers]

I believe that Data Warehouse Cloud does support join push-down and filter push-down for some connections but it doesn't seem easy to understand what connection do or don't support these features.

I've read that they are "typically supported in database to database" scenarios but that's a little vague.

I also know that you can look at the Remote Query logs to see what joins/filters are perhaps being applied - but again that's a little hit/miss.

Is there any documentation specifically around this.

[kpsauer · Accepted solution]

For the SDI based connections this is documented. Check the Data Warehouse Cloud documentation for connection. For each connection you find more details there and also a link to the SDI documentation.

Let me make an example to illustrate it:

For the SAP HANA on-prem connection you find more information. On the bottom of this page you find a link to the SDI documentation, where you find further details. On the SAP HANA adapter page you will find supported push down features for SELECT statement like like GROUP BY, WHERE Clause, TOP, LIMIT and others.

It works very similar for other connections.

Best regards
KP Sauer

[MattRogers · Accepted solution]

Thanks Klaus-Peter. This is really helpful.

[Sven_Knpfler]

There is also this system view "SYS"."ADAPTER_CAPABILITIES" that gives you detailed information about the capabilities of each adapter in regard to push down (SDA) and real time replication (CDC):

https://help.sap.com/viewer/c1d3f60099654ecfb3fe36ac93c121bb/2021_4_QRC/en-US/a1fcde3545984c14a92cfb...

[MattRogers]

Thanks Sven - really useful information to know - much appreciated!