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Overview
| Comment: | Performance optimization to the moveToRoot() subroutine in btree.c. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
b5842a70f8e26456a8f0d39539bc266f |
| User & Date: | drh 2013-12-06 23:25:27 |
Context
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2013-12-07
| ||
| 16:56 | At the start of each journaled write transaction, check to see if the database file has been moved, and if it has refuse to start the transaction, returning an SQLITE_READONLY_DBMOVED error code. Writing to a moved or renamed database is still allowed when journal_mode is OFF or MEMORY. check-in: 369a23e0 user: drh tags: trunk | |
|
2013-12-06
| ||
| 23:25 | Performance optimization to the moveToRoot() subroutine in btree.c. check-in: b5842a70 user: drh tags: trunk | |
| 22:45 | Use memcmp() instead of the BINARY collating function where possible, for a performance boost. check-in: c5a3a1af user: drh tags: trunk | |
Changes
Changes to src/btree.c.
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** indicating a table b-tree, or if the caller did specify a KeyInfo
** structure the flags byte is set to 0x02 or 0x0A, indicating an index
** b-tree).
*/
static int moveToRoot(BtCursor *pCur){
MemPage *pRoot;
int rc = SQLITE_OK;
Btree *p = pCur->pBtree;
BtShared *pBt = p->pBt;
assert( cursorHoldsMutex(pCur) );
assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
assert( CURSOR_VALID < CURSOR_REQUIRESEEK );
assert( CURSOR_FAULT > CURSOR_REQUIRESEEK );
if( pCur->eState>=CURSOR_REQUIRESEEK ){
if( pCur->eState==CURSOR_FAULT ){
................................................................................
assert( pCur->skipNext!=SQLITE_OK );
return pCur->skipNext;
}
sqlite3BtreeClearCursor(pCur);
}
if( pCur->iPage>=0 ){
int i;
for(i=1; i<=pCur->iPage; i++){
releasePage(pCur->apPage[i]);
}
pCur->iPage = 0;
}else if( pCur->pgnoRoot==0 ){
pCur->eState = CURSOR_INVALID;
return SQLITE_OK;
}else{
rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0],
pCur->wrFlag==0 ? PAGER_GET_READONLY : 0);
if( rc!=SQLITE_OK ){
pCur->eState = CURSOR_INVALID;
return rc;
}
pCur->iPage = 0;
................................................................................
assert( pRoot->isInit && (pCur->pKeyInfo==0)==pRoot->intKey );
pCur->aiIdx[0] = 0;
pCur->info.nSize = 0;
pCur->atLast = 0;
pCur->validNKey = 0;
if( pRoot->nCell==0 && !pRoot->leaf ){
Pgno subpage;
if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
pCur->eState = CURSOR_VALID;
rc = moveToChild(pCur, subpage);
}else{
pCur->eState = ((pRoot->nCell>0)?CURSOR_VALID:CURSOR_INVALID);
}
return rc;
}
/*
** Move the cursor down to the left-most leaf entry beneath the
** entry to which it is currently pointing.
|
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** indicating a table b-tree, or if the caller did specify a KeyInfo
** structure the flags byte is set to 0x02 or 0x0A, indicating an index
** b-tree).
*/
static int moveToRoot(BtCursor *pCur){
MemPage *pRoot;
int rc = SQLITE_OK;
assert( cursorHoldsMutex(pCur) );
assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
assert( CURSOR_VALID < CURSOR_REQUIRESEEK );
assert( CURSOR_FAULT > CURSOR_REQUIRESEEK );
if( pCur->eState>=CURSOR_REQUIRESEEK ){
if( pCur->eState==CURSOR_FAULT ){
................................................................................
assert( pCur->skipNext!=SQLITE_OK );
return pCur->skipNext;
}
sqlite3BtreeClearCursor(pCur);
}
if( pCur->iPage>=0 ){
while( pCur->iPage ) releasePage(pCur->apPage[pCur->iPage--]);
}else if( pCur->pgnoRoot==0 ){
pCur->eState = CURSOR_INVALID;
return SQLITE_OK;
}else{
rc = getAndInitPage(pCur->pBtree->pBt, pCur->pgnoRoot, &pCur->apPage[0],
pCur->wrFlag==0 ? PAGER_GET_READONLY : 0);
if( rc!=SQLITE_OK ){
pCur->eState = CURSOR_INVALID;
return rc;
}
pCur->iPage = 0;
................................................................................
assert( pRoot->isInit && (pCur->pKeyInfo==0)==pRoot->intKey );
pCur->aiIdx[0] = 0;
pCur->info.nSize = 0;
pCur->atLast = 0;
pCur->validNKey = 0;
if( pRoot->nCell>0 ){
pCur->eState = CURSOR_VALID;
}else if( !pRoot->leaf ){
Pgno subpage;
if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
pCur->eState = CURSOR_VALID;
rc = moveToChild(pCur, subpage);
}else{
pCur->eState = CURSOR_INVALID;
}
return rc;
}
/*
** Move the cursor down to the left-most leaf entry beneath the
** entry to which it is currently pointing.
|