Op 18-02-10 18:23, Stefan Manegold schreef: > On Thu, Feb 18, 2010 at 05:46:31PM +0100, Stefan de Konink wrote: >> Attached is a trace of a single column select operation, with a max, >> avg and equality. >> >> The equality takes about 4 times more time than the avg operation. >> >> From the plan I see that the operation is executed paralel, but I do >> wonder why suddenly the uselect takes such a high amount of time. > > Which version of MonetDB?
CVS HEAD, 2 am. > How configured / compiled? --enable-assert --enable-debug > How was the mserver5 started (which command line options were given)? /opt/monetdb-head/bin/mserver5 --dbfarm=/home/skinkie/monetb --dbname=kvk --dbinit="include sphinx; include sql;" --set mapi_port=50001 > Any changes compared to the default monetdb5.conf? No, not changed anything in there. > Is the "kvk" column sorted? No, it does include a partial sort (msb are sorted). A 32bit column (kvks) that is (or either should be...) ends up with between 170ms ~ 220ms. > Could you run the select query in the MAL debugger > (DEBUG select kvk from kvk where kvk = 412657690010;), > single step through it, > set the debug mask to 2097152 > (debug 2097152) > just before the algebra.uselect() is executed, > and report the output on the server console after the algebra.uselect() has > been executed? Do you mean this? mdb># _44 := algebra.uselect(_40=<tmp_5710>:bat[:oid,:lng][1196532],A0=412657690010:lng); mdb> #BAT_select_(b=tmp_5710): sampling: tmp1 = BATslice(b=tmp_5710, _lo=598266, _hi=598371); #BAT_select_(b=tmp_5710): sampling: tmp2 = BAT_select_(tmp1=tmp_5704, tl, th, tail); #BAT_select_(b=tmp_5704): BAT_scanselect(b=tmp_5704, bn=tmp_5703, tl, th, equi=1, nequi=0, lval=1, hval=1, nocheck=1); #seqscan_eq_lng_void_tloc_oid_vid_nocheck_noinc[if ( simple_EQ(tl ,v,lng) ),v,oid_ctr,oid_ctr++;](b=tmp_5704, bn=tmp_5703, tl, th, oid_ctr=598266, str_idx=0); #BAT_select_(b=tmp_5704): tmp_5703: hkey=1, tkey=0, hsorted=139659451564097, tsorted=0. #BAT_select_(b=tmp_5710): BAT_hashselect(b=tmp_5710, bn=tmp_5703, tl); (building hash-table on the fly) #BAThash: create hash(1196532); #BAT_select_(b=tmp_5710): tmp_5703: hkey=1, tkey=0, hsorted=139659451564032, tsorted=139659451564032. Stefan ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Monetdb-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/monetdb-developers
