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.
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