Hello, I'm new to monetdb and installed it two weeks ago to do some tests. I was very much impressed with the speed on large tables, but in some of my latest tests regarding subparts of these tables based on a unix timestamp the time was the same as querying the whole table. Does anyone know what I can do to get higher speeds on queries in monetdb that only use part of the table, like partition pruning, explicit foreign keys or unique statements, indexes or some other way? I have the following two tables and number of records: CREATE TABLE table1 (T1vid INT NOT NULL, T1Field1 VARCHAR(20) NOT NULL, T1Field2 TINYINT NOT NULL); This table has about 400.000 records. The records are non time bounded, it's just a list. The T1vid is an increased ID, but not generated in momentdb at the moment, but in mysql CREATE TABLE table2 (T2mid INT NOT NULL, T2vid INT NOT NULL, T2timestamp INT NOT NULL, T2Field1 INT NOT NULL, T2Field2 INT NOT NULL); This table has about 1.000.000 records and a unix_timestamp field. It get a few new records every second and records older then 24 hours are deleted. The T2mid-field refers to some other table that's not in momentdb's database, so just an integer. The T2vid-field however refers to the T1vid-field in table1 (a foreign key, but i didn't define it that way). The following query takes about 3,5 seconds, it doesnt't have the timestamp included in the WHERE-clause: SELECT SUM(t2.T2Field2), t1.T1Field1, t1.T1Field2, (t2.T2timestamp / 3600) as interval FROM table2 AS t2 LEFT JOIN table 1 AS t1 ON t1.T1vid=t2.T2vid WHERE t2.T2Field1=8 AND t2.T2vid IN (*list of 15 unique v.T1vid ID's*) GROUP BY interval, t1.T1Field1, t1.T1Field2 ORDER BY interval DESC; Resulting is a list of the 15 v.T1vid ID's times the number of interval's. t2.T2timestamp is now devided by 3600 and grouped on this result, so each set of 15 v.T1vid ID's would reflect 1 hour, returning max 24x15 rows. ** The following query also takes about 3,5 seconds, but it does have the timestamp included in the WHERE-clause. It only needs to access 1 hour of data instead of the whole 24 hours, and groups it into intervals of 5 minutes (300 sec): SELECT SUM(t2.T2Field2), t1.T1Field1, t1.T1Field2, (t2.T2timestamp / 300) as interval FROM table2 AS t2 LEFT JOIN table 1 AS t1 ON t1.T1vid=t2.T2vid WHERE* t2.T2timestamp BETWEEN 1298360000 AND 1298363600* AND t2.T2Field1=8 AND t2.T2vid IN (*list of 15 unique v.T1vid ID's*) GROUP BY interval, t1.T1Field1, t1.T1Field2 ORDER BY interval DESC; t2.T2timestamp is now devided by 300, so each set of 15 v.T1vid ID's would reflect 5 minuntes, returning max 12x15 rows. I would very much appreciate any help or hints; please let me know any question you might have. Kind regards, Rob Berentsen