Hi, please, i have on server as 3.750 mb as ubuntu 12.04, one processor and 2.000 mhz. I install here monetdb and have 12.000,000 millions of rows. I had one problem as one query. For example this query block database: select "timedimension"."namemonth" as "c0", "bi_con_cdr_diario"."comnombre2" as "c1", "bi_con_cdr_diario"."succodigo" as "c2", sum("bi_con_cdr_diario"."minutosfacturados") as "m0" from "timedimension" as "timedimension", "bi_con_cdr_diario" as "bi_con_cdr_diario" where "bi_con_cdr_diario"."idtimedimension" = "timedimension"."id" and "bi_con_cdr_diario"."comcodigo" = '4' group by "timedimension"."namemonth", "bi_con_cdr_diario"."comnombre2", "bi_con_cdr_diario"."succodigo" if i delete (and "bi_con_cdr_diario"."comcodigo" = '4' ) this work fine. Too i im testing very others querys and work fine, but why this not work and block database? Thaks for your help. Edgar M