;-)

Dank je wel! --- Niet alleen voor deze, maar met naam ook voor de hele nieuwe group-by code en al die andere nieuwe schone code!!!

Stefan

On Tue, Aug 21, 2012 at 12:43:42PM +0200, Sjoerd Mullender wrote:

Changeset: 6f001c03cd8d for MonetDB URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=6f001c03cd8d Modified Files: gdk/gdk_group.c Branch: default Log Message:

Implemented another trivial case for grouping: all equal values.

diffs (122 lines):

diff --git a/gdk/gdk_group.c b/gdk/gdk_group.c --- a/gdk/gdk_group.c +++ b/gdk/gdk_group.c @@ -44,11 +44,14 @@

• is always created. In other words, the groups argument may not be
• NULL, but the extents and histo arguments may be NULL.

• • There are five different implementations of the grouping code.

• • There are six different implementations of the grouping code.
  • If it can be trivially determined that all groups are singletons,
  • we can produce the outputs trivially.
• • If all values in b are known to be equal (both sorted and reverse
• • sorted), we produce a single group or copy the input group.
• • If the input bats b and g are sorted, or if the subsorted flag is
  • set (only used by BATsubsort), we only need to compare consecutive
  • values.

@@ -102,6 +105,7 @@ BATgroup_internal(BAT **groups, BAT **ex

if (b->tkey || BATcount(b) <= 1 || (g && (g->tkey || BATtdense(g)))) { /* grouping is trivial: 1 element per group */

• ALGODEBUG fprintf(stderr, "#BATgroup: trivial case: 1 element per group\n");
  

  if (BATcount(b) == 1 && b->htype == TYPE_oid) ngrp = * (oid *) Hloc(b, BUNfirst(b)); else

@@ -132,6 +136,62 @@ BATgroup_internal(BAT **groups, BAT **ex } return GDK_SUCCEED; }

• if (b->tsorted && b->trevsorted) {

• /* all values are equal */
  

• if (g == NULL) {
  

• 	/* there's only a single group: 0 */
  

• 	ALGODEBUG fprintf(stderr, "#BATgroup: trivial case: single output group\n");
  

• 	ngrp = 0;
  

• 	gn = BATconstant(TYPE_oid, &ngrp, BATcount(b));
  

• 	if (gn == NULL)
  

• 		goto error;
  

• 	BATseqbase(gn, b->hseqbase);
  

• 	*groups = gn;
  

• 	if (extents) {
  

• 		ngrp = gn->hseqbase;
  

• 		en = BATconstant(TYPE_void, &ngrp, 1);
  

• 		if (en == NULL)
  

• 			goto error;
  

• 		BATseqbase(BATmirror(en), ngrp);
  

• 		*extents = en;
  

• 	}
  

• 	if (histo) {
  

• 		wrd cnt = (wrd) BATcount(b);
  

• 		hn = BATconstant(TYPE_wrd, &cnt, 1);
  

• 		if (hn == NULL)
  

• 			goto error;
  

• 		*histo = hn;
  

• 	}
  

• 	return GDK_SUCCEED;
  

• }
  

• if ((extents == NULL) == (e == NULL) &&
  

•     (histo == NULL) == (h == NULL)) {
  

• 	/* inherit given grouping; note that if
  

• 	 * extents/histo is to be returned, we need
  

• 	 * e/h available in order to copy them,
  

• 	 * otherwise we will need to calculate them
  

• 	 * which we will do using the "normal" case */
  

• 	ALGODEBUG fprintf(stderr, "#BATgroup: trivial case: copy input groups\n");
  

• 	gn = BATcopy(g, g->htype, g->ttype, 0);
  

• 	if (gn == NULL)
  

• 		goto error;
  

• 	*groups = gn;
  

• 	if (extents) {
  

• 		en = BATcopy(e, e->htype, e->ttype, 0);
  

• 		if (en == NULL)
  

• 			goto error;
  

• 		*extents = en;
  

• 	}
  

• 	if (histo) {
  

• 		hn = BATcopy(h, h->htype, h->ttype, 0);
  

• 		if (hn == NULL)
  

• 			goto error;
  

• 		*histo = hn;
  

• 	}
  

• 	return GDK_SUCCEED;
  

• }
  

• } assert(g == NULL || !BATtdense(g)); /* i.e. g->ttype == TYPE_oid */ bi = bat_iterator(b); cmp = BATatoms[b->ttype].atomCmp;

@@ -167,6 +227,7 @@ BATgroup_internal(BAT **groups, BAT **ex (g == NULL || g->tsorted || g->trevsorted)) || subsorted) { /* we only need to compare each entry with the previous */

• ALGODEBUG fprintf(stderr, "#BATgroup: compare consecutive values\n");
  

  if (grps) prev = *grps++; pv = BUNtail(bi, BUNfirst(b));

@@ -220,6 +281,7 @@ BATgroup_internal(BAT **groups, BAT **ex /* for each value, we need to scan all previous equal * values (a consecutive, possibly empty, range) to * see if we can find one in the same old group */

• ALGODEBUG fprintf(stderr, "#BATgroup: subscan old groups\n");
  

  pv = BUNtail(bi, BUNfirst(b)); ngrps[0] = ngrp; if (extents)

@@ -284,6 +346,7 @@ BATgroup_internal(BAT **groups, BAT **ex } } else if (b->T->hash) { /* we already have a hash table on b */

• ALGODEBUG fprintf(stderr, "#BATgroup: use existing hash table\n");
  

  hs = b->T->hash; for (r = BUNfirst(b), p = r, q = r + BATcount(b); p < q; p++) { v = BUNtail(bi, p);

@@ -343,6 +406,7 @@ BATgroup_internal(BAT **groups, BAT **ex * build an incomplete hash table on the fly--also see * BATassertHeadProps and BATderiveHeadProps for * similar code */

• ALGODEBUG fprintf(stderr, "#BATgroup: create partial hash table\n");
  

  nme = BBP_physical(b->batCacheid); nmelen = strlen(nme); if ((hp = GDKzalloc(sizeof(Heap))) == NULL ||

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