On 26/12/14 13:44, Vijay Krishna wrote:

Hi,

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.

Dataflow blocks mark a parallel block;
https://www.monetdb.org/Documentation/Manuals/MonetDB/Optimizers/Dataflow1

  * *Is there any reference guide to understand the output of EXPLAIN/TRACE? Or should we refer to the source code to understand this?
    *

https://www.monetdb.org/Documentation/Manuals/SQLreference/Runtime

  * *Is it possible to know the query plan that Monet arrives to execute a query?

Explain always shows the plan to be executed.

    *
  * *Is it possible to make the output of EXPLAIN/TRACE to be in SQL format, like in MySQL?*

You can use EXPLAIN/PLAN/TRACE to inspect the plans generated
https://www.monetdb.org/Documentation/Manuals/SQLreference/Runtime


Success, Martin

Any help much appreciated.


Thanks & Regards,

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


_______________________________________________
users-list mailing list
users-list@monetdb.org
https://www.monetdb.org/mailman/listinfo/users-list

_______________________________________________
users-list mailing list
users-list@monetdb.org
https://www.monetdb.org/mailman/listinfo/users-list