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Simplify the CellInfo structure for a size reduction and performance

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improvement.

FossilOrigin-Name: bf59df66b3613c38cfb13a68091b8328ebb22c78
This commit is contained in:
drh
2014-09-23 21:25:19 +00:00
parent 3b8fea9ec6
commit ab1cc58b70
4 changed files with 38 additions and 48 deletions
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60
src/btree.c
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@@ -977,38 +977,33 @@ static void btreeParseCellPtr(
u8 *pCell, /* Pointer to the cell text. */
CellInfo *pInfo /* Fill in this structure */
){
u16 n; /* Number bytes in cell content header */
u8 *pIter = &pCell[pPage->childPtrSize];
u32 nPayload; /* Number of bytes of cell payload */
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
pInfo->pCell = pCell;
assert( pPage->leaf==0 || pPage->leaf==1 );
n = pPage->childPtrSize;
assert( n==4-4*pPage->leaf );
if( pPage->intKey ){
if( pPage->hasData ){
assert( n==0 );
n = getVarint32(pCell, nPayload);
assert( pIter==pCell );
pIter += getVarint32(pIter, nPayload);
}else{
nPayload = 0;
}
n += getVarint(&pCell[n], (u64*)&pInfo->nKey);
pInfo->nData = nPayload;
pIter += getVarint(pIter, (u64*)&pInfo->nKey);
}else{
pInfo->nData = 0;
n += getVarint32(&pCell[n], nPayload);
pIter += getVarint32(pIter, nPayload);
pInfo->nKey = nPayload;
}
pInfo->nPayload = nPayload;
pInfo->nHeader = n;
pInfo->pPayload = pIter;
testcase( nPayload==pPage->maxLocal );
testcase( nPayload==pPage->maxLocal+1 );
if( likely(nPayload<=pPage->maxLocal) ){
if( nPayload<=pPage->maxLocal ){
/* This is the (easy) common case where the entire payload fits
** on the local page. No overflow is required.
*/
if( (pInfo->nSize = (u16)(n+nPayload))<4 ) pInfo->nSize = 4;
pInfo->nSize = nPayload + (u16)(pIter - pCell);
if( pInfo->nSize<4 ) pInfo->nSize = 4;
pInfo->nLocal = (u16)nPayload;
pInfo->iOverflow = 0;
}else{
@@ -1035,7 +1030,7 @@ static void btreeParseCellPtr(
}else{
pInfo->nLocal = (u16)minLocal;
}
pInfo->iOverflow = (u16)(pInfo->nLocal + n);
pInfo->iOverflow = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell);
pInfo->nSize = pInfo->iOverflow + 4;
}
}
@@ -1132,7 +1127,6 @@ static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
if( *pRC ) return;
assert( pCell!=0 );
btreeParseCellPtr(pPage, pCell, &info);
assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
if( info.iOverflow ){
Pgno ovfl = get4byte(&pCell[info.iOverflow]);
ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
@@ -3866,8 +3860,9 @@ int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
assert( cursorHoldsMutex(pCur) );
assert( pCur->eState==CURSOR_VALID );
assert( pCur->apPage[pCur->iPage]->intKey==1 );
getCellInfo(pCur);
*pSize = pCur->info.nData;
*pSize = pCur->info.nPayload;
return SQLITE_OK;
}
@@ -4018,7 +4013,6 @@ static int accessPayload(
){
unsigned char *aPayload;
int rc = SQLITE_OK;
u32 nKey;
int iIdx = 0;
MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
BtShared *pBt = pCur->pBt; /* Btree this cursor belongs to */
@@ -4033,15 +4027,13 @@ static int accessPayload(
assert( eOp!=2 || offset==0 ); /* Always start from beginning for eOp==2 */
getCellInfo(pCur);
aPayload = pCur->info.pCell + pCur->info.nHeader;
nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);
aPayload = pCur->info.pPayload;
#ifdef SQLITE_DIRECT_OVERFLOW_READ
bEnd = (offset+amt==nKey+pCur->info.nData);
bEnd = offset+amt==pCur->info.nPayload;
#endif
assert( offset+amt <= pCur->info.nPayload );
if( NEVER(offset+amt > nKey+pCur->info.nData)
|| &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
){
if( &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize] ){
/* Trying to read or write past the end of the data is an error */
return SQLITE_CORRUPT_BKPT;
}
@@ -4275,7 +4267,7 @@ static const void *fetchPayload(
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
assert( pCur->info.nSize>0 );
*pAmt = pCur->info.nLocal;
return (void*)(pCur->info.pCell + pCur->info.nHeader);
return (void*)pCur->info.pPayload;
}
@@ -5640,9 +5632,10 @@ static int fillInCell(
}
nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
btreeParseCellPtr(pPage, pCell, &info);
assert( info.nHeader==nHeader );
assert( nHeader=(int)(info.pPayload - pCell) );
assert( info.nKey==nKey );
assert( info.nData==(u32)(nData+nZero) );
assert( pPage->intKey==0 || info.nPayload==(u32)(nData+nZero) );
assert( pPage->intKey==1 || info.nPayload==nKey );
/* Fill in the payload */
nPayload = nData + nZero;
@@ -8086,19 +8079,18 @@ static int checkTreePage(
"On tree page %d cell %d: ", iPage, i);
pCell = findCell(pPage,i);
btreeParseCellPtr(pPage, pCell, &info);
sz = info.nData;
if( !pPage->intKey ) sz += (int)info.nKey;
sz = info.nPayload;
/* For intKey pages, check that the keys are in order.
*/
else if( i==0 ) nMinKey = nMaxKey = info.nKey;
else{
if( info.nKey <= nMaxKey ){
if( pPage->intKey ){
if( i==0 ){
nMinKey = nMaxKey = info.nKey;
}else if( info.nKey <= nMaxKey ){
checkAppendMsg(pCheck, zContext,
"Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
"Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
}
nMaxKey = info.nKey;
}
assert( sz==info.nPayload );
if( (sz>info.nLocal)
&& (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
){