September 2016 - developers-list

GDK_mmap_minsize again
by Hannes Mühleisen 24 Sep '16

24 Sep '16

Hello list, we were wondering about the purpose of GDK_mmap_minsize when creating transient columns. The attached patch will always *try* to malloc/realloc a transient column but still fall back to memory-mapped files if malloc should fail. This dramatically improves performance. Any good reason why this should not be the default behaviour? Thanks, Mark and Hannes

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eviction in Monetdb
by Narendra Pradeep 15 Sep '16

15 Sep '16

Hello , Need to know about monetdb eviction policy ? My understanding is Monetdb creates a buffer pool {BBP} and inserts all the bats that are used . But not sure when does Monetdb deletes the bat from the buffer pool and what eviction policy does it use (like LRU or based on some threshold) ? Thanks

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Re: MonetDB: graph1 - Add the operator bat.getCount() to retrieve th...
by Stefan Manegold 14 Sep '16

14 Sep '16

Hi Dean, how is bat.getCount() different from aggr.count() ? ;-) Thanks! Stefan ----- On Sep 14, 2016, at 6:30 PM, Dean De Leo commits+dleo=cwi.nl(a)monetdb.org wrote: > Changeset: 9ac831deacb3 for MonetDB > URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=9ac831deacb3 > Modified Files: > monetdb5/modules/kernel/bat5.c > monetdb5/modules/kernel/bat5.h > monetdb5/modules/kernel/bat5.mal > Branch: graph1 > Log Message: > > Add the operator bat.getCount() to retrieve the cardinality of a bat > > > diffs (48 lines): > > diff --git a/monetdb5/modules/kernel/bat5.c b/monetdb5/modules/kernel/bat5.c > --- a/monetdb5/modules/kernel/bat5.c > +++ b/monetdb5/modules/kernel/bat5.c > @@ -496,6 +496,19 @@ BKCgetColumnType(str *res, const bat *bi > } > > str > +BKCgetCount(lng *res, const bat *bid) > +{ > + *res = lng_nil; > + if (BBPcheck(*bid, "bat.getCount")) { > + BAT *b = BBPquickdesc(*bid, 0); > + > + if (b != NULL) > + *res = (lng) BATcount(b); > + } > + return MAL_SUCCEED; > +} > + > +str > BKCgetRole(str *res, const bat *bid) > { > BAT *b; > diff --git a/monetdb5/modules/kernel/bat5.h b/monetdb5/modules/kernel/bat5.h > --- a/monetdb5/modules/kernel/bat5.h > +++ b/monetdb5/modules/kernel/bat5.h > @@ -29,6 +29,7 @@ mal_export str BKCbun_inplace_force(bat > mal_export str BKCbat_inplace_force(bat *r, const bat *bid, const bat *rid, > const bat *uid, const bit *force); > mal_export str BKCgetCapacity(lng *res, const bat *bid); > mal_export str BKCgetColumnType(str *res, const bat *bid); > +mal_export str BKCgetCount(lng *res, const bat *bid); > mal_export str BKCgetRole(str *res, const bat *bid); > mal_export str BKCsetkey(bat *res, const bat *bid, const bit *param); > mal_export str BKCisSorted(bit *res, const bat *bid); > diff --git a/monetdb5/modules/kernel/bat5.mal b/monetdb5/modules/kernel/bat5.mal > --- a/monetdb5/modules/kernel/bat5.mal > +++ b/monetdb5/modules/kernel/bat5.mal > @@ -77,6 +77,10 @@ command getCapacity(b:bat[:any_1]):lng > address BKCgetCapacity > comment "Returns the current allocation size (in max number of elements) of a > BAT."; > > +command getCount(b:bat[:any_1]):lng > +address BKCgetCount > +comment "Returns the current tuple count of a BAT."; > + > command getColumnType( b:bat[:any_1] ) :str > address BKCgetColumnType > comment "Returns the type of the tail column of a BAT, as an integer type > number."; > _______________________________________________ > checkin-list mailing list > checkin-list(a)monetdb.org > https://www.monetdb.org/mailman/listinfo/checkin-list -- | Stefan.Manegold(a)CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |

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