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Overview
| Comment: | Performance improvements in moveToChild() by shifting some work over to getAndInitPage(). Net improvement is about 800K cycles at cost of 30 bytes. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
1956a4ce8eca650d98a7f68fd2d82eb8 |
| User & Date: | drh 2015-06-27 19:45:03 |
Context
|
2015-06-27
| ||
| 20:55 | Enhancements to the previous check-in to make it a little smaller and faster. check-in: 291d9e0c user: drh tags: trunk | |
| 19:45 | Performance improvements in moveToChild() by shifting some work over to getAndInitPage(). Net improvement is about 800K cycles at cost of 30 bytes. check-in: 1956a4ce user: drh tags: trunk | |
| 15:51 | Manually inline the call from getAndInitPage() to btreeGetPage() for a savings of 2.5 million cycles at a cost of less than 100 bytes. check-in: 7f65b96b user: drh tags: trunk | |
Changes
Changes to src/btree.c.
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u32 sqlite3BtreeLastPage(Btree *p){
assert( sqlite3BtreeHoldsMutex(p) );
assert( ((p->pBt->nPage)&0x8000000)==0 );
return btreePagecount(p->pBt);
}
/*
** Get a page from the pager and initialize it. This routine is just a
** convenience wrapper around separate calls to btreeGetPage() and
** btreeInitPage().
**
** If an error occurs, then the value *ppPage is set to is undefined. It
** may remain unchanged, or it may be set to an invalid value.
*/
static int getAndInitPage(
BtShared *pBt, /* The database file */
Pgno pgno, /* Number of the page to get */
MemPage **ppPage, /* Write the page pointer here */
int bReadonly /* PAGER_GET_READONLY or 0 */
){
int rc;
assert( sqlite3_mutex_held(pBt->mutex) );
assert( bReadonly==PAGER_GET_READONLY || bReadonly==0 );
if( pgno>btreePagecount(pBt) ){
rc = SQLITE_CORRUPT_BKPT;
}else{
DbPage *pDbPage;
rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, bReadonly);
if( rc ) return rc;
*ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
if( (*ppPage)->isInit==0 ){
rc = btreeInitPage(*ppPage);
if( rc!=SQLITE_OK ){
releasePage(*ppPage);
}
}
}
testcase( pgno==0 );
assert( pgno!=0 || rc==SQLITE_CORRUPT );
return rc;
}
/*
** Release a MemPage. This should be called once for each prior
** call to btreeGetPage.
*/
................................................................................
pCur->pgnoRoot = (Pgno)iTable;
pCur->iPage = -1;
pCur->pKeyInfo = pKeyInfo;
pCur->pBtree = p;
pCur->pBt = pBt;
assert( wrFlag==0 || wrFlag==BTCF_WriteFlag );
pCur->curFlags = wrFlag;
pCur->pNext = pBt->pCursor;
if( pCur->pNext ){
pCur->pNext->pPrev = pCur;
}
pBt->pCursor = pCur;
pCur->eState = CURSOR_INVALID;
return SQLITE_OK;
................................................................................
**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){
int rc;
int i = pCur->iPage;
MemPage *pNewPage;
BtShared *pBt = pCur->pBt;
assert( cursorHoldsMutex(pCur) );
assert( pCur->eState==CURSOR_VALID );
assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
assert( pCur->iPage>=0 );
if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
return SQLITE_CORRUPT_BKPT;
}
rc = getAndInitPage(pBt, newPgno, &pNewPage,
(pCur->curFlags & BTCF_WriteFlag)==0 ? PAGER_GET_READONLY : 0);
if( rc ) return rc;
pCur->apPage[i+1] = pNewPage;
pCur->aiIdx[i+1] = 0;
pCur->iPage++;
pCur->info.nSize = 0;
pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
if( pNewPage->nCell<1 || pNewPage->intKey!=pCur->apPage[i]->intKey ){
return SQLITE_CORRUPT_BKPT;
}
return SQLITE_OK;
}
#if SQLITE_DEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of
................................................................................
assert( pCur->apPage[pCur->iPage]!=0 );
releasePageNotNull(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->curFlags & BTCF_WriteFlag)==0 ? PAGER_GET_READONLY : 0);
if( rc!=SQLITE_OK ){
pCur->eState = CURSOR_INVALID;
return rc;
}
pCur->iPage = 0;
}
pRoot = pCur->apPage[0];
................................................................................
if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
pRight = &pParent->aData[pParent->hdrOffset+8];
}else{
pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
}
pgno = get4byte(pRight);
while( 1 ){
rc = getAndInitPage(pBt, pgno, &apOld[i], 0);
if( rc ){
memset(apOld, 0, (i+1)*sizeof(MemPage*));
goto balance_cleanup;
}
nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
if( (i--)==0 ) break;
................................................................................
int hdr;
u16 szCell;
assert( sqlite3_mutex_held(pBt->mutex) );
if( pgno>btreePagecount(pBt) ){
return SQLITE_CORRUPT_BKPT;
}
rc = getAndInitPage(pBt, pgno, &pPage, 0);
if( rc ) return rc;
if( pPage->bBusy ){
rc = SQLITE_CORRUPT_BKPT;
goto cleardatabasepage_out;
}
pPage->bBusy = 1;
hdr = pPage->hdrOffset;
|
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u32 sqlite3BtreeLastPage(Btree *p){
assert( sqlite3BtreeHoldsMutex(p) );
assert( ((p->pBt->nPage)&0x8000000)==0 );
return btreePagecount(p->pBt);
}
/*
** Get a page from the pager and initialize it.
**
** If pCur!=0 then the page acquired will be added to that cursor.
** If the fetch fails, this routine must decrement pCur->iPage.
**
** The page is fetched as read-write unless pCur is not NULL and is
** a read-only cursor.
**
** If an error occurs, then *ppPage is undefined. It
** may remain unchanged, or it may be set to an invalid value.
*/
static int getAndInitPage(
BtShared *pBt, /* The database file */
Pgno pgno, /* Number of the page to get */
MemPage **ppPage, /* Write the page pointer here */
BtCursor *pCur, /* Cursor to receive the page, or NULL */
int bReadOnly /* True for a read-only page */
){
int rc;
DbPage *pDbPage;
assert( sqlite3_mutex_held(pBt->mutex) );
assert( pCur==0 || ppPage==&pCur->apPage[pCur->iPage] );
assert( pCur==0 || bReadOnly==pCur->curPagerFlags );
if( pgno>btreePagecount(pBt) ){
rc = SQLITE_CORRUPT_BKPT;
goto getAndInitPage_error;
}
rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, bReadOnly);
if( rc ){
goto getAndInitPage_error;
}
*ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
if( (*ppPage)->isInit==0 ){
rc = btreeInitPage(*ppPage);
if( rc!=SQLITE_OK ){
releasePage(*ppPage);
goto getAndInitPage_error;
}
}
/* If obtaining a page for a cursor, we must verify that the page is
** compatible with the cursor */
if( pCur && pCur->iPage>0
&& ((*ppPage)->nCell<1 || (*ppPage)->intKey!=pCur->apPage[0]->intKey)
){
rc = SQLITE_CORRUPT_BKPT;
releasePage(*ppPage);
goto getAndInitPage_error;
}
testcase( pgno==0 );
assert( pgno!=0 || rc==SQLITE_CORRUPT );
return SQLITE_OK;
getAndInitPage_error:
if( pCur ) pCur->iPage--;
return rc;
}
/*
** Release a MemPage. This should be called once for each prior
** call to btreeGetPage.
*/
................................................................................
pCur->pgnoRoot = (Pgno)iTable;
pCur->iPage = -1;
pCur->pKeyInfo = pKeyInfo;
pCur->pBtree = p;
pCur->pBt = pBt;
assert( wrFlag==0 || wrFlag==BTCF_WriteFlag );
pCur->curFlags = wrFlag;
pCur->curPagerFlags = wrFlag ? 0 : PAGER_GET_READONLY;
pCur->pNext = pBt->pCursor;
if( pCur->pNext ){
pCur->pNext->pPrev = pCur;
}
pBt->pCursor = pCur;
pCur->eState = CURSOR_INVALID;
return SQLITE_OK;
................................................................................
**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){
BtShared *pBt = pCur->pBt;
assert( cursorHoldsMutex(pCur) );
assert( pCur->eState==CURSOR_VALID );
assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
assert( pCur->iPage>=0 );
if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
return SQLITE_CORRUPT_BKPT;
}
pCur->info.nSize = 0;
pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
pCur->iPage++;
pCur->aiIdx[pCur->iPage] = 0;
return getAndInitPage(pBt, newPgno, &pCur->apPage[pCur->iPage],
pCur, pCur->curPagerFlags);
}
#if SQLITE_DEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of
................................................................................
assert( pCur->apPage[pCur->iPage]!=0 );
releasePageNotNull(pCur->apPage[pCur->iPage--]);
}
}else if( pCur->pgnoRoot==0 ){
pCur->eState = CURSOR_INVALID;
return SQLITE_OK;
}else{
assert( pCur->iPage==(-1) );
pCur->iPage = 0;
rc = getAndInitPage(pCur->pBtree->pBt, pCur->pgnoRoot, &pCur->apPage[0],
pCur, pCur->curPagerFlags);
if( rc!=SQLITE_OK ){
pCur->eState = CURSOR_INVALID;
return rc;
}
pCur->iPage = 0;
}
pRoot = pCur->apPage[0];
................................................................................
if( (i+nxDiv-pParent->nOverflow)==pParent->nCell ){
pRight = &pParent->aData[pParent->hdrOffset+8];
}else{
pRight = findCell(pParent, i+nxDiv-pParent->nOverflow);
}
pgno = get4byte(pRight);
while( 1 ){
rc = getAndInitPage(pBt, pgno, &apOld[i], 0, 0);
if( rc ){
memset(apOld, 0, (i+1)*sizeof(MemPage*));
goto balance_cleanup;
}
nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
if( (i--)==0 ) break;
................................................................................
int hdr;
u16 szCell;
assert( sqlite3_mutex_held(pBt->mutex) );
if( pgno>btreePagecount(pBt) ){
return SQLITE_CORRUPT_BKPT;
}
rc = getAndInitPage(pBt, pgno, &pPage, 0, 0);
if( rc ) return rc;
if( pPage->bBusy ){
rc = SQLITE_CORRUPT_BKPT;
goto cleardatabasepage_out;
}
pPage->bBusy = 1;
hdr = pPage->hdrOffset;
|
Changes to src/btreeInt.h.
514 515 516 517 518 519 520 521 522 523 524 525 526 527 |
i64 nKey; /* Size of pKey, or last integer key */
void *pKey; /* Saved key that was cursor last known position */
Pgno pgnoRoot; /* The root page of this tree */
int nOvflAlloc; /* Allocated size of aOverflow[] array */
int skipNext; /* Prev() is noop if negative. Next() is noop if positive.
** Error code if eState==CURSOR_FAULT */
u8 curFlags; /* zero or more BTCF_* flags defined below */
u8 eState; /* One of the CURSOR_XXX constants (see below) */
u8 hints; /* As configured by CursorSetHints() */
i16 iPage; /* Index of current page in apPage */
u16 aiIdx[BTCURSOR_MAX_DEPTH]; /* Current index in apPage[i] */
MemPage *apPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
};
|
> |
514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 |
i64 nKey; /* Size of pKey, or last integer key */
void *pKey; /* Saved key that was cursor last known position */
Pgno pgnoRoot; /* The root page of this tree */
int nOvflAlloc; /* Allocated size of aOverflow[] array */
int skipNext; /* Prev() is noop if negative. Next() is noop if positive.
** Error code if eState==CURSOR_FAULT */
u8 curFlags; /* zero or more BTCF_* flags defined below */
u8 curPagerFlags; /* Flags to send to sqlite3PagerAcquire() */
u8 eState; /* One of the CURSOR_XXX constants (see below) */
u8 hints; /* As configured by CursorSetHints() */
i16 iPage; /* Index of current page in apPage */
u16 aiIdx[BTCURSOR_MAX_DEPTH]; /* Current index in apPage[i] */
MemPage *apPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
};
|