Hi,

I have been studying on the slow query behavior with certain joins in MonetDB. I use explain & trace statements to understand the flow.

But, I couldn't actually understand the MAL statements that appear as the output of EXPLAIN/TRACE statements.

I tried learning MAL with this reference - https://www.monetdb.org/Documentation/Manuals/MonetDB/MALreference

But it had no explanations for system defined MAL statements that appear in trace.

For example, from the trace statement, I could find that a lot of time was spent in the MAL expression "language.dataflow()", but without actually knowing what does this step actually do, I am unable to optimize the query.

Is there any reference guide to understand the output of EXPLAIN/TRACE? Or should we refer to the source code to understand this?
Is it possible to know the query plan that Monet arrives to execute a query?
Is it possible to make the output of EXPLAIN/TRACE to be in SQL format, like in MySQL?

Any help much appreciated.

Thanks & Regards,

Vijayakrishna.P.
Mobile : (+91) 9500402305.