Limits of Pushdown

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There are limiting factors to the ability to push down queries. If there are multiple data sources connected on the Data Virtuality Platform, a query spanning multiple databases can not be pushed down completely, so some operations will have to be executed in Data Virtuality’s memory (or, to be more exact, in the buffer space, which will be discussed below)

As an example, two different databases of the same MSSQL server can be joined when querying it directly. If a different connection represents each database, the performance will be mitigated because Data Virtuality interprets them as different sources. A way to work around this behaviour is to create a view on the MSSQL server that joins them already on the MSSQL server side.