Hi all,

we're testing MonetDB performances in order to understand if it could be possible to use it as data mart in our BI software.

We're considering a set of queries executed in our test environment (CentOS 7, 32 GB RAM, 4 cpu).

All the executed queries have quite good performances (between 10 and 45 seconds) except the following one that is taking several minutes in order to be executed:

SELECT id, count(distinct value)

FROM table

GROUP BY id;

The table contains 100 millions of data. It has about 130 columns (varchar, int, bigint, smallint, tinyint, timestamp, datetime). We have no BLOB/CLOB/Text types.

The fields used in the query have these data types:

id: int

value: bigint

Can you suggest us any optimizations in order to have this query run faster? Do you know some possible reasons why it's so slow?

Kind Regards,

Alfio Bettini