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Change BtreeMoveto so that it can be biased to the right or to the center.

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Use a right bias when appending and a center bias when searching.  This
gives about a 15% reduction in calls to sqlite3VdbeRecordCompare. (CVS 3741)

FossilOrigin-Name: ad4a6b1a91bcefd8a4c75e8dc99c1153c72c31a3
This commit is contained in:
drh
2007-03-29 05:51:49 +00:00
parent f1d68b3096
commit e4d9081307
13 changed files with 101 additions and 67 deletions
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23
src/btree.c
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@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.344 2007/03/29 04:43:26 drh Exp $
** $Id: btree.c,v 1.345 2007/03/29 05:51:49 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
@@ -728,7 +728,7 @@ static int restoreOrClearCursorPositionX(BtCursor *pCur, int doSeek){
assert( pCur->eState==CURSOR_REQUIRESEEK );
pCur->eState = CURSOR_INVALID;
if( doSeek ){
rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, &pCur->skip);
rc = sqlite3BtreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &pCur->skip);
}
if( rc==SQLITE_OK ){
sqliteFree(pCur->pKey);
@@ -3303,7 +3303,13 @@ int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
** *pRes>0 The cursor is left pointing at an entry that
** is larger than pKey.
*/
int sqlite3BtreeMoveto(BtCursor *pCur, const void *pKey, i64 nKey, int *pRes){
int sqlite3BtreeMoveto(
BtCursor *pCur, /* The cursor to be moved */
const void *pKey, /* The key content for indices. Not used by tables */
i64 nKey, /* Size of pKey. Or the key for tables */
int biasRight, /* If true, bias the search to the high end */
int *pRes /* Search result flag */
){
int rc;
rc = moveToRoot(pCur);
if( rc ) return rc;
@@ -3324,7 +3330,11 @@ int sqlite3BtreeMoveto(BtCursor *pCur, const void *pKey, i64 nKey, int *pRes){
if( !pPage->intKey && pKey==0 ){
return SQLITE_CORRUPT_BKPT;
}
pCur->idx = upr;
if( biasRight ){
pCur->idx = upr;
}else{
pCur->idx = (upr+lwr)/2;
}
if( lwr<=upr ) for(;;){
void *pCellKey;
i64 nCellKey;
@@ -5182,7 +5192,8 @@ static int checkReadLocks(Btree *pBtree, Pgno pgnoRoot, BtCursor *pExclude){
int sqlite3BtreeInsert(
BtCursor *pCur, /* Insert data into the table of this cursor */
const void *pKey, i64 nKey, /* The key of the new record */
const void *pData, int nData /* The data of the new record */
const void *pData, int nData, /* The data of the new record */
int appendBias /* True if this is likely an append */
){
int rc;
int loc;
@@ -5208,7 +5219,7 @@ int sqlite3BtreeInsert(
restoreOrClearCursorPosition(pCur, 0);
if(
SQLITE_OK!=(rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur)) ||
SQLITE_OK!=(rc = sqlite3BtreeMoveto(pCur, pKey, nKey, &loc))
SQLITE_OK!=(rc = sqlite3BtreeMoveto(pCur, pKey, nKey, appendBias, &loc))
){
return rc;
}