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Improve page split in rtree emulation. Now if splitted result has

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big misalignement, then it tries to split page basing on distribution
of boxe's centers.

Per report from  Dolafi, Tom <dolafit@janelia.hhmi.org>

 Backpatch is needed, change doesn't affect on-disk storage.
This commit is contained in:
Teodor Sigaev 2007-09-07 17:04:26 +00:00
parent 978de9d06d
commit 0392ea5097
1 changed files with 36 additions and 47 deletions
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83
src/backend/access/gist/gistproc.c
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@ -10,7 +10,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/access/gist/gistproc.c,v 1.10 2007/01/05 22:19:22 momjian Exp $
* $PostgreSQL: pgsql/src/backend/access/gist/gistproc.c,v 1.11 2007/09/07 17:04:26 teodor Exp $
*
*-------------------------------------------------------------------------
*/
@ -21,13 +21,6 @@
#include "utils/geo_decls.h"
typedef struct
{
BOX *key;
int pos;
} KBsort;
static int compare_KB(const void *a, const void *b);
static bool gist_box_leaf_consistent(BOX *key, BOX *query,
StrategyNumber strategy);
static double size_box(Datum dbox);
@ -194,22 +187,6 @@ gist_box_penalty(PG_FUNCTION_ARGS)
PG_RETURN_POINTER(result);
}
/*
* qsort comparator for box areas
*/
static int
compare_KB(const void *a, const void *b)
{
BOX *abox = ((const KBsort *) a)->key;
BOX *bbox = ((const KBsort *) b)->key;
double sa = (abox->high.x - abox->low.x) * (abox->high.y - abox->low.y);
double sb = (bbox->high.x - bbox->low.x) * (bbox->high.y - bbox->low.y);
if (sa == sb)
return 0;
return (sa > sb) ? 1 : -1;
}
static void
chooseLR(GIST_SPLITVEC *v,
OffsetNumber *list1, int nlist1, BOX *union1,
@ -417,44 +394,56 @@ gist_box_picksplit(PG_FUNCTION_ARGS)
ADDLIST(listT, unionT, posT, i);
}
/* bad disposition, sort by ascending and resplit */
if ((posR == 0 || posL == 0) && (posT == 0 || posB == 0))
#define LIMIT_RATIO 0.1
#define _IS_BADRATIO(x,y) ( (y) == 0 || (float)(x)/(float)(y) < LIMIT_RATIO )
#define IS_BADRATIO(x,y) ( _IS_BADRATIO((x),(y)) || _IS_BADRATIO((y),(x)) )
/* bad disposition, try to split by centers of boxes */
if ( IS_BADRATIO(posR, posL) && IS_BADRATIO(posT, posB) )
{
KBsort *arr = (KBsort *) palloc(sizeof(KBsort) * maxoff);
double avgCenterX=0.0, avgCenterY=0.0;
double CenterX, CenterY;
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
cur = DatumGetBoxP(entryvec->vector[i].key);
avgCenterX += ((double)cur->high.x + (double)cur->low.x)/2.0;
avgCenterY += ((double)cur->high.y + (double)cur->low.y)/2.0;
}
avgCenterX /= maxoff;
avgCenterY /= maxoff;
posL = posR = posB = posT = 0;
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
arr[i - 1].key = DatumGetBoxP(entryvec->vector[i].key);
arr[i - 1].pos = i;
}
qsort(arr, maxoff, sizeof(KBsort), compare_KB);
for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
{
cur = arr[i - 1].key;
if (cur->low.x - pageunion.low.x < pageunion.high.x - cur->high.x)
ADDLIST(listL, unionL, posL, arr[i - 1].pos);
else if (cur->low.x - pageunion.low.x == pageunion.high.x - cur->high.x)
cur = DatumGetBoxP(entryvec->vector[i].key);
CenterX = ((double)cur->high.x + (double)cur->low.x)/2.0;
CenterY = ((double)cur->high.y + (double)cur->low.y)/2.0;
if (CenterX < avgCenterX)
ADDLIST(listL, unionL, posL, i);
else if (CenterX == avgCenterX)
{
if (posL > posR)
ADDLIST(listR, unionR, posR, arr[i - 1].pos);
ADDLIST(listR, unionR, posR, i);
else
ADDLIST(listL, unionL, posL, arr[i - 1].pos);
ADDLIST(listL, unionL, posL, i);
}
else
ADDLIST(listR, unionR, posR, arr[i - 1].pos);
ADDLIST(listR, unionR, posR, i);
if (cur->low.y - pageunion.low.y < pageunion.high.y - cur->high.y)
ADDLIST(listB, unionB, posB, arr[i - 1].pos);
else if (cur->low.y - pageunion.low.y == pageunion.high.y - cur->high.y)
if (CenterY < avgCenterY)
ADDLIST(listB, unionB, posB, i);
else if (CenterY == avgCenterY)
{
if (posB > posT)
ADDLIST(listT, unionT, posT, arr[i - 1].pos);
ADDLIST(listT, unionT, posT, i);
else
ADDLIST(listB, unionB, posB, arr[i - 1].pos);
ADDLIST(listB, unionB, posB, i);
}
else
ADDLIST(listT, unionT, posT, arr[i - 1].pos);
else
ADDLIST(listT, unionT, posT, i);
}
}