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Currently,only the first column of multi-column indices 

is used to find start scan position of Indexscan-s.

To speed up finding scan start position,I have changed
_bt_first() to use as many keys as possible.

I'll attach the patch here.

Regards.

Hiroshi Inoue
This commit is contained in:
Bruce Momjian 1999-09-27 18:20:21 +00:00
parent 62045e67eb
commit 7b2a8e4e56
2 changed files with 92 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

130
src/backend/access/nbtree/nbtsearch.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.53 1999/07/17 20:16:43 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsearch.c,v 1.54 1999/09/27 18:20:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -727,11 +727,15 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
RegProcedure proc;
int result;
BTScanOpaque so;
ScanKeyData skdata;
Size keysok;
int i;
int nKeyIndex = -1;
bool strategyCheck;
ScanKey scankeys = 0;
int keysCount = 0;
int *nKeyIs = 0;
int i, j;
StrategyNumber strat_total;
rel = scan->relation;
so = (BTScanOpaque) scan->opaque;
@ -742,38 +746,57 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
so->numberOfFirstKeys = 0; /* may be changed by _bt_orderkeys */
so->qual_ok = 1; /* may be changed by _bt_orderkeys */
scan->scanFromEnd = false;
strategyCheck = false;
if (so->numberOfKeys > 0)
{
_bt_orderkeys(rel, so);
if (ScanDirectionIsBackward(dir))
if (so->qual_ok)
strategyCheck = true;
}
strat_total = BTEqualStrategyNumber;
if (strategyCheck)
{
AttrNumber attno;
nKeyIs = (int *)palloc(so->numberOfKeys*sizeof(int));
for (i=0; i < so->numberOfKeys; i++)
{
for (i = 0; i < so->numberOfKeys; i++)
attno = so->keyData[i].sk_attno;
if (attno == keysCount)
continue;
if (attno > keysCount + 1)
break;
strat = _bt_getstrat(rel, attno,
so->keyData[i].sk_procedure);
if (strat == strat_total ||
strat == BTEqualStrategyNumber)
{
if (so->keyData[i].sk_attno != 1)
nKeyIs[keysCount++] = i;
continue;
}
if (ScanDirectionIsBackward(dir) &&
(strat == BTLessStrategyNumber ||
strat == BTLessEqualStrategyNumber) )
{
nKeyIs[keysCount++] = i;
strat_total = strat;
if (strat == BTLessStrategyNumber)
break;
strat = _bt_getstrat(rel, so->keyData[i].sk_attno,
so->keyData[i].sk_procedure);
if (strat == BTLessStrategyNumber ||
strat == BTLessEqualStrategyNumber ||
strat == BTEqualStrategyNumber)
{
nKeyIndex = i;
continue;
}
if (ScanDirectionIsForward(dir) &&
(strat == BTGreaterStrategyNumber ||
strat == BTGreaterEqualStrategyNumber) )
{
nKeyIs[keysCount++] = i;
strat_total = strat;
if (strat == BTGreaterStrategyNumber)
break;
}
continue;
}
}
else
{
strat = _bt_getstrat(rel, 1, so->keyData[0].sk_procedure);
if (strat == BTLessStrategyNumber ||
strat == BTLessEqualStrategyNumber)
;
else
nKeyIndex = 0;
}
if (nKeyIndex < 0)
if (!keysCount)
scan->scanFromEnd = true;
}
else
@ -784,7 +807,11 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
/* if we just need to walk down one edge of the tree, do that */
if (scan->scanFromEnd)
{
if (nKeyIs)
pfree(nKeyIs);
return _bt_endpoint(scan, dir);
}
itupdesc = RelationGetDescr(rel);
current = &(scan->currentItemData);
@ -796,16 +823,24 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
* at the right place in the scan.
*/
/* _bt_orderkeys disallows it, but it's place to add some code latter */
if (so->keyData[0].sk_flags & SK_ISNULL)
scankeys = (ScanKey)palloc(keysCount*sizeof(ScanKeyData));
for (i=0; i < keysCount; i++)
{
elog(ERROR, "_bt_first: btree doesn't support is(not)null, yet");
return (RetrieveIndexResult) NULL;
j = nKeyIs[i];
if (so->keyData[j].sk_flags & SK_ISNULL)
{
pfree(nKeyIs);
pfree(scankeys);
elog(ERROR, "_bt_first: btree doesn't support is(not)null, yet");
return ((RetrieveIndexResult) NULL);
}
proc = index_getprocid(rel, i+1, BTORDER_PROC);
ScanKeyEntryInitialize(scankeys+i, so->keyData[j].sk_flags,
i+1, proc, so->keyData[j].sk_argument);
}
proc = index_getprocid(rel, 1, BTORDER_PROC);
ScanKeyEntryInitialize(&skdata, so->keyData[nKeyIndex].sk_flags,
1, proc, so->keyData[nKeyIndex].sk_argument);
if (nKeyIs) pfree(nKeyIs);
stack = _bt_search(rel, 1, &skdata, &buf);
stack = _bt_search(rel, keysCount, scankeys, &buf);
_bt_freestack(stack);
blkno = BufferGetBlockNumber(buf);
@ -823,6 +858,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
ItemPointerSetInvalid(current);
so->btso_curbuf = InvalidBuffer;
_bt_relbuf(rel, buf, BT_READ);
pfree(scankeys);
return (RetrieveIndexResult) NULL;
}
maxoff = PageGetMaxOffsetNumber(page);
@ -835,7 +871,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
*/
while (maxoff == P_HIKEY && !P_RIGHTMOST(pop) &&
_bt_skeycmp(rel, 1, &skdata, page,
_bt_skeycmp(rel, keysCount, scankeys, page,
PageGetItemId(page, P_HIKEY),
BTGreaterEqualStrategyNumber))
{
@ -849,6 +885,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
ItemPointerSetInvalid(current);
so->btso_curbuf = InvalidBuffer;
_bt_relbuf(rel, buf, BT_READ);
pfree(scankeys);
return (RetrieveIndexResult) NULL;
}
maxoff = PageGetMaxOffsetNumber(page);
@ -857,7 +894,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
/* find the nearest match to the manufactured scan key on the page */
offnum = _bt_binsrch(rel, buf, 1, &skdata, BT_DESCENT);
offnum = _bt_binsrch(rel, buf, keysCount, scankeys, BT_DESCENT);
if (offnum > maxoff)
{
@ -872,12 +909,11 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
* we're looking for minus the value we're looking at in the index.
*/
result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum);
result = _bt_compare(rel, itupdesc, page, keysCount, scankeys, offnum);
/* it's yet other place to add some code latter for is(not)null */
strat = _bt_getstrat(rel, 1, so->keyData[nKeyIndex].sk_procedure);
strat = strat_total;
switch (strat)
{
case BTLessStrategyNumber:
@ -890,7 +926,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
offnum = ItemPointerGetOffsetNumber(current);
page = BufferGetPage(buf);
result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum);
result = _bt_compare(rel, itupdesc, page, keysCount, scankeys, offnum);
} while (result <= 0);
}
@ -906,12 +942,11 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
offnum = ItemPointerGetOffsetNumber(current);
page = BufferGetPage(buf);
result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum);
result = _bt_compare(rel, itupdesc, page, keysCount, scankeys, offnum);
} while (result >= 0);
if (result < 0)
_bt_twostep(scan, &buf, BackwardScanDirection);
}
if (result < 0)
_bt_twostep(scan, &buf, BackwardScanDirection);
break;
case BTEqualStrategyNumber:
@ -920,6 +955,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
_bt_relbuf(scan->relation, buf, BT_READ);
so->btso_curbuf = InvalidBuffer;
ItemPointerSetInvalid(&(scan->currentItemData));
pfree(scankeys);
return (RetrieveIndexResult) NULL;
}
else if (ScanDirectionIsBackward(dir))
@ -931,7 +967,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
offnum = ItemPointerGetOffsetNumber(current);
page = BufferGetPage(buf);
result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum);
result = _bt_compare(rel, itupdesc, page, keysCount, scankeys, offnum);
} while (result == 0);
if (result < 0)
@ -950,6 +986,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
_bt_relbuf(scan->relation, buf, BT_READ);
so->btso_curbuf = InvalidBuffer;
ItemPointerSetInvalid(&(scan->currentItemData));
pfree(scankeys);
return (RetrieveIndexResult) NULL;
}
}
@ -974,7 +1011,7 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
page = BufferGetPage(buf);
offnum = ItemPointerGetOffsetNumber(current);
result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum);
result = _bt_compare(rel, itupdesc, page, keysCount, scankeys, offnum);
} while (result < 0);
if (result > 0)
@ -993,12 +1030,13 @@ _bt_first(IndexScanDesc scan, ScanDirection dir)
offnum = ItemPointerGetOffsetNumber(current);
page = BufferGetPage(buf);
result = _bt_compare(rel, itupdesc, page, 1, &skdata, offnum);
result = _bt_compare(rel, itupdesc, page, keysCount, scankeys, offnum);
} while (result >= 0);
}
break;
}
pfree(scankeys);
/* okay, current item pointer for the scan is right */
offnum = ItemPointerGetOffsetNumber(current);
page = BufferGetPage(buf);

10
src/backend/access/nbtree/nbtutils.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtutils.c,v 1.32 1999/07/17 20:16:43 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtutils.c,v 1.33 1999/09/27 18:20:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -101,6 +101,7 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
uint16 numberOfKeys = so->numberOfKeys;
uint16 new_numberOfKeys = 0;
AttrNumber attno = 1;
bool equalStrategyEnd, underEqualStrategy;
if (numberOfKeys < 1)
return;
@ -136,6 +137,8 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
for (j = 0; j <= BTMaxStrategyNumber; j++)
init[j] = 0;
equalStrategyEnd = false;
underEqualStrategy = true;
/* check each key passed in */
for (i = 0;;)
{
@ -150,6 +153,7 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
if (cur->sk_attno != attno + 1 && i < numberOfKeys)
elog(ERROR, "_bt_orderkeys: key(s) for attribute %d missed", attno + 1);
underEqualStrategy = (!equalStrategyEnd);
/*
* If = has been specified, no other key will be used. In case
* of key < 2 && key == 1 and so on we have to set qual_ok to
@ -175,6 +179,8 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
init[BTGreaterEqualStrategyNumber - 1] = 0;
init[BTGreaterStrategyNumber - 1] = 0;
}
else
equalStrategyEnd = true;
/* only one of <, <= */
if (init[BTLessStrategyNumber - 1]
@ -223,7 +229,7 @@ _bt_orderkeys(Relation relation, BTScanOpaque so)
if (init[j])
key[new_numberOfKeys++] = xform[j];
if (attno == 1)
if (underEqualStrategy)
so->numberOfFirstKeys = new_numberOfKeys;
if (i == numberOfKeys)