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Performance improvements in sqlite3BtreeMovetoUnpacked().

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FossilOrigin-Name: d0fb7acea7cbfe6f2d84782a28bb51675a06576f
This commit is contained in:
drh
2013-11-25 02:38:55 +00:00
parent 93307e9d06
commit ec3e6b10f4
3 changed files with 51 additions and 43 deletions
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77
src/btree.c
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@@ -4647,10 +4647,10 @@ int sqlite3BtreeMovetoUnpacked(
}
assert( pCur->apPage[0]->intKey || pIdxKey );
for(;;){
int lwr, upr, idx;
int lwr, upr, idx, c;
Pgno chldPg;
MemPage *pPage = pCur->apPage[pCur->iPage];
int c;
u8 *pCell; /* Pointer to current cell in pPage */
/* pPage->nCell must be greater than zero. If this is the root-page
** the cursor would have been INVALID above and this for(;;) loop
@@ -4667,30 +4667,45 @@ int sqlite3BtreeMovetoUnpacked(
}else{
pCur->aiIdx[pCur->iPage] = (u16)(idx = (upr+lwr)/2);
}
for(;;){
u8 *pCell; /* Pointer to current cell in pPage */
pCur->info.nSize = 0;
if( pPage->intKey ){
assert( idx==pCur->aiIdx[pCur->iPage] );
pCur->info.nSize = 0;
pCell = findCell(pPage, idx) + pPage->childPtrSize;
if( pPage->intKey ){
for(;;){
i64 nCellKey;
pCell = findCell(pPage, idx) + pPage->childPtrSize;
if( pPage->hasData ){
u32 dummy;
pCell += getVarint32(pCell, dummy);
}
getVarint(pCell, (u64*)&nCellKey);
if( nCellKey==intKey ){
c = 0;
pCur->validNKey = 1;
pCur->info.nKey = nCellKey;
if( !pPage->leaf ){
lwr = idx;
break;
}else{
*pRes = 0;
rc = SQLITE_OK;
goto moveto_finish;
}
}else if( nCellKey<intKey ){
c = -1;
lwr = idx+1;
}else{
assert( nCellKey>intKey );
c = +1;
upr = idx-1;
}
pCur->validNKey = 1;
pCur->info.nKey = nCellKey;
}else{
if( lwr>upr ) break;
pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);
}
}else{
for(;;){
int nCell;
assert( idx==pCur->aiIdx[pCur->iPage] );
pCell = findCell(pPage, idx) + pPage->childPtrSize;
/* The maximum supported page-size is 65536 bytes. This means that
** the maximum number of record bytes stored on an index B-Tree
** page is less than 16384 bytes and may be stored as a 2-byte
@@ -4699,7 +4714,7 @@ int sqlite3BtreeMovetoUnpacked(
** stored entirely within the b-tree page by inspecting the first
** 2 bytes of the cell.
*/
int nCell = pCell[0];
nCell = pCell[0];
if( nCell<=pPage->max1bytePayload
/* && (pCell+nCell)<pPage->aDataEnd */
){
@@ -4738,47 +4753,37 @@ int sqlite3BtreeMovetoUnpacked(
c = sqlite3VdbeRecordCompare(nCell, pCellKey, pIdxKey);
sqlite3_free(pCellKey);
}
}
if( c==0 ){
if( pPage->intKey && !pPage->leaf ){
lwr = idx;
break;
}else{
if( c==0 ){
*pRes = 0;
rc = SQLITE_OK;
goto moveto_finish;
}
if( c<0 ){
lwr = idx+1;
}else{
upr = idx-1;
}
if( lwr>upr ) break;
pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);
}
if( c<0 ){
lwr = idx+1;
}else{
upr = idx-1;
}
if( lwr>upr ){
break;
}
pCur->aiIdx[pCur->iPage] = (u16)(idx = (lwr+upr)/2);
}
assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
assert( pPage->isInit );
if( pPage->leaf ){
chldPg = 0;
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
*pRes = c;
rc = SQLITE_OK;
goto moveto_finish;
}else if( lwr>=pPage->nCell ){
chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
}else{
chldPg = get4byte(findCell(pPage, lwr));
}
if( chldPg==0 ){
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
*pRes = c;
rc = SQLITE_OK;
goto moveto_finish;
}
pCur->aiIdx[pCur->iPage] = (u16)lwr;
pCur->info.nSize = 0;
pCur->validNKey = 0;
rc = moveToChild(pCur, chldPg);
if( rc ) goto moveto_finish;
if( rc ) break;
}
moveto_finish:
return rc;