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Performance improvement in sqlite3BtreeNext() and sqlite3BtreePrevious()

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for the common case of a valid cursor.

FossilOrigin-Name: dc65ad8c4c67b21e3b042b8df6580d02b634a90b
This commit is contained in:
drh
2013-08-19 20:04:10 +00:00
parent 2c18788ffa
commit f66f26a311
3 changed files with 38 additions and 30 deletions
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52
src/btree.c
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@@ -4796,21 +4796,25 @@ int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
MemPage *pPage;
assert( cursorHoldsMutex(pCur) );
rc = restoreCursorPosition(pCur);
if( rc!=SQLITE_OK ){
return rc;
}
assert( pRes!=0 );
if( CURSOR_INVALID==pCur->eState ){
*pRes = 1;
return SQLITE_OK;
if( pCur->eState!=CURSOR_VALID ){
rc = restoreCursorPosition(pCur);
if( rc!=SQLITE_OK ){
return rc;
}
if( CURSOR_INVALID==pCur->eState ){
*pRes = 1;
return SQLITE_OK;
}
}
if( pCur->skipNext>0 ){
if( pCur->skipNext ){
if( pCur->skipNext>0 ){
pCur->skipNext = 0;
*pRes = 0;
return SQLITE_OK;
}
pCur->skipNext = 0;
*pRes = 0;
return SQLITE_OK;
}
pCur->skipNext = 0;
pPage = pCur->apPage[pCur->iPage];
idx = ++pCur->aiIdx[pCur->iPage];
@@ -4870,21 +4874,25 @@ int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
MemPage *pPage;
assert( cursorHoldsMutex(pCur) );
rc = restoreCursorPosition(pCur);
if( rc!=SQLITE_OK ){
return rc;
}
pCur->atLast = 0;
if( CURSOR_INVALID==pCur->eState ){
*pRes = 1;
return SQLITE_OK;
if( pCur->eState!=CURSOR_VALID ){
if( ALWAYS(pCur->eState>=CURSOR_REQUIRESEEK) ){
rc = btreeRestoreCursorPosition(pCur);
if( rc!=SQLITE_OK ) return rc;
}
if( CURSOR_INVALID==pCur->eState ){
*pRes = 1;
return SQLITE_OK;
}
}
if( pCur->skipNext<0 ){
if( pCur->skipNext ){
if( pCur->skipNext<0 ){
pCur->skipNext = 0;
*pRes = 0;
return SQLITE_OK;
}
pCur->skipNext = 0;
*pRes = 0;
return SQLITE_OK;
}
pCur->skipNext = 0;
pPage = pCur->apPage[pCur->iPage];
assert( pPage->isInit );