On 21/02/16 20:26, Stefan Manegold wrote:

Hi,

(as a side note, I'm afraid I'm too "old fashioned" and do no longer understand "modern" MonetDB traces; at least, I have no idea, why there are so many prepare statements calls/traces in your trace of a simple select count(*) query ... )

Having said that, the trace suggests that your machine either has 6 cores, or MonetDB has decided to split it in 6 slices for processing, although you machine has only 4 cores?

Also, the trace reveals that the vast majority of the time is spent in 6 (one per slice) sql.tid() calls:

$ grep sql.tid monet.log | 1474764656 | X_43=[14960273]:bat[:oid,:oid]{horigin=6, torigin=6} := sql.tid(X_2=0:int,"sys":str,"zoombox_movimentos":str,5:int,6:int); 1474 seconds to load 112 MB illustrates either a severe memory resource competition of a pretty lousy IO system. An overloaded machine.

| 1483639788 | X_33=[16225905]:bat[:oid,:oid]{horigin=1, torigin=1} := sql.tid(X_2=0:int,"sys":str,"zoombox_movimentos":str,0:int,6:int); | 1483894651 | X_37=[16225905]:bat[:oid,:oid]{horigin=3, torigin=3} := sql.tid(X_2=0:int,"sys":str,"zoombox_movimentos":str,2:int,6:int); | 1484040668 | X_39=[16225905]:bat[:oid,:oid]{horigin=4, torigin=4} := sql.tid(X_2=0:int,"sys":str,"zoombox_movimentos":str,3:int,6:int); | 1484137364 | X_41=[16225905]:bat[:oid,:oid]{horigin=5, torigin=5} := sql.tid(X_2=0:int,"sys":str,"zoombox_movimentos":str,4:int,6:int); | 4274477065 | X_35=[16225905]:bat[:oid,:oid]{horigin=2, torigin=2} := sql.tid(X_2=0:int,"sys":str,"zoombox_movimentos":str,1:int,6:int);

Again, I reached the limits of my up-to-date knowledge of MonetDB to know what these do and why they take so long.

Maybe some else knows more ...

Stefan

----- On Feb 21, 2016, at 7:54 PM, Luciano Sasso luciano@gsgroup.com.br wrote:

...

Hi, send attached trace for query.

Att,

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