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Add the MemPage.noPayload boolean and use it to help

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cellSizePtr() and btreeParseCellPtr() run faster.

FossilOrigin-Name: 8e3375313ebbf26b68561f3ed31d2a488222e5d0
This commit is contained in:
drh
2014-09-24 00:59:08 +00:00
parent c46838309c
commit 3e28ff5cb5
4 changed files with 56 additions and 52 deletions
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85
src/btree.c
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@@ -974,20 +974,25 @@ static void btreeParseCellPtr(
u8 *pCell, /* Pointer to the cell text. */
CellInfo *pInfo /* Fill in this structure */
){
u8 *pIter = &pCell[pPage->childPtrSize];
u8 *pIter; /* For scanning through pCell */
u32 nPayload; /* Number of bytes of cell payload */
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
assert( pPage->leaf==0 || pPage->leaf==1 );
if( pPage->intKey ){
if( pPage->hasData ){
assert( pIter==pCell );
pIter += getVarint32(pIter, nPayload);
}else{
nPayload = 0;
}
if( pPage->intKeyLeaf ){
assert( pPage->childPtrSize==0 );
pIter = pCell + getVarint32(pCell, nPayload);
pIter += getVarint(pIter, (u64*)&pInfo->nKey);
}else if( pPage->noPayload ){
assert( pPage->childPtrSize==4 );
pInfo->nSize = 4 + getVarint(&pCell[4], (u64*)&pInfo->nKey);
pInfo->nPayload = 0;
pInfo->nLocal = 0;
pInfo->iOverflow = 0;
pInfo->pPayload = 0;
return;
}else{
pIter = pCell + pPage->childPtrSize;
pIter += getVarint32(pIter, nPayload);
pInfo->nKey = nPayload;
}
@@ -1046,9 +1051,9 @@ static void btreeParseCell(
** the space used by the cell pointer.
*/
static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
u8 *pIter = &pCell[pPage->childPtrSize];
u8 *pEnd;
u32 nSize;
u8 *pIter = pCell + pPage->childPtrSize; /* For looping over bytes of pCell */
u8 *pEnd; /* End mark for a varint */
u32 nSize; /* Size value to return */
#ifdef SQLITE_DEBUG
/* The value returned by this function should always be the same as
@@ -1059,19 +1064,21 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
btreeParseCellPtr(pPage, pCell, &debuginfo);
#endif
if( pPage->intKey==0 || pPage->hasData ){
nSize = *pIter;
if( nSize>=0x80 ){
pEnd = &pIter[9];
nSize &= 0x7f;
do{
nSize = (nSize<<7) | (*++pIter & 0x7f);
}while( *(pIter)>=0x80 && pIter<pEnd );
}
pIter++;
}else{
nSize = 0;
if( pPage->noPayload ){
pEnd = &pIter[9];
while( (*pIter++)&0x80 && pIter<pEnd );
assert( pPage->childPtrSize==4 );
return (u16)(pIter - pCell);
}
nSize = *pIter;
if( nSize>=0x80 ){
pEnd = &pIter[9];
nSize &= 0x7f;
do{
nSize = (nSize<<7) | (*++pIter & 0x7f);
}while( *(pIter)>=0x80 && pIter<pEnd );
}
pIter++;
if( pPage->intKey ){
/* pIter now points at the 64-bit integer key value, a variable length
** integer. The following block moves pIter to point at the first byte
@@ -1079,10 +1086,12 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
pEnd = &pIter[9];
while( (*pIter++)&0x80 && pIter<pEnd );
}
testcase( nSize==pPage->maxLocal );
testcase( nSize==pPage->maxLocal+1 );
if( nSize>pPage->maxLocal ){
if( nSize<=pPage->maxLocal ){
nSize += (u32)(pIter - pCell);
if( nSize<4 ) nSize = 4;
}else{
int minLocal = pPage->minLocal;
nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
testcase( nSize==pPage->maxLocal );
@@ -1090,15 +1099,8 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
if( nSize>pPage->maxLocal ){
nSize = minLocal;
}
nSize += 4;
nSize += 4 + (u16)(pIter - pCell);
}
nSize += (u32)(pIter - pCell);
/* The minimum size of any cell is 4 bytes. */
if( nSize<4 ){
nSize = 4;
}
assert( nSize==debuginfo.nSize || CORRUPT_DB );
return (u16)nSize;
}
@@ -1442,12 +1444,14 @@ static int decodeFlags(MemPage *pPage, int flagByte){
pBt = pPage->pBt;
if( flagByte==(PTF_LEAFDATA | PTF_INTKEY) ){
pPage->intKey = 1;
pPage->hasData = pPage->leaf;
pPage->intKeyLeaf = pPage->leaf;
pPage->noPayload = !pPage->leaf;
pPage->maxLocal = pBt->maxLeaf;
pPage->minLocal = pBt->minLeaf;
}else if( flagByte==PTF_ZERODATA ){
pPage->intKey = 0;
pPage->hasData = 0;
pPage->intKeyLeaf = 0;
pPage->noPayload = 0;
pPage->maxLocal = pBt->maxLocal;
pPage->minLocal = pBt->minLocal;
}else{
@@ -3855,7 +3859,7 @@ 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 );
assert( pCur->apPage[pCur->iPage]->intKeyLeaf==1 );
getCellInfo(pCur);
*pSize = pCur->info.nPayload;
return SQLITE_OK;
@@ -4690,7 +4694,7 @@ int sqlite3BtreeMovetoUnpacked(
for(;;){
i64 nCellKey;
pCell = findCell(pPage, idx) + pPage->childPtrSize;
if( pPage->hasData ){
if( pPage->intKeyLeaf ){
while( 0x80 <= *(pCell++) ){
if( pCell>=pPage->aDataEnd ) return SQLITE_CORRUPT_BKPT;
}
@@ -5617,8 +5621,7 @@ static int fillInCell(
/* Fill in the header. */
nHeader = pPage->childPtrSize;
nPayload = nData + nZero;
if( pPage->hasData ){
assert( pPage->intKey );
if( pPage->intKeyLeaf ){
nHeader += putVarint32(&pCell[nHeader], nPayload);
}else{
assert( nData==0 );
@@ -6391,7 +6394,7 @@ static int balance_nonroot(
** leafData: 1 if pPage holds key+data and pParent holds only keys.
*/
leafCorrection = apOld[0]->leaf*4;
leafData = apOld[0]->hasData;
leafData = apOld[0]->intKeyLeaf;
for(i=0; i<nOld; i++){
int limit;
@@ -6967,7 +6970,7 @@ static int balance(BtCursor *pCur){
rc = sqlite3PagerWrite(pParent->pDbPage);
if( rc==SQLITE_OK ){
#ifndef SQLITE_OMIT_QUICKBALANCE
if( pPage->hasData
if( pPage->intKeyLeaf
&& pPage->nOverflow==1
&& pPage->aiOvfl[0]==pPage->nCell
&& pParent->pgno!=1