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Split out a new variant of cellSizePtr() that applies only to leaf pages,

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for a small performance increase.

FossilOrigin-Name: 22d32eef8741ae4f2aac3869465e5a7d2e33c6bc2425dd8e77f2a746e43687e8
This commit is contained in:
drh
2023-02-25 16:03:28 +00:00
parent 20e09ba6a8
commit 2d7829057e
3 changed files with 55 additions and 11 deletions
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52
src/btree.c
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@@ -1328,10 +1328,11 @@ static void btreeParseCell(
**
** cellSizePtrNoPayload() => table internal nodes
** cellSizePtrTableLeaf() => table leaf nodes
** cellSizePtr() => all index nodes & table leaf nodes
** cellSizePtr() => index internal nodes
** cellSizeIdxLeaf() => index leaf nodes
*/
static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
u8 *pIter = pCell + pPage->childPtrSize; /* For looping over bytes of pCell */
u8 *pIter = pCell + 4; /* For looping over bytes of pCell */
u8 *pEnd; /* End mark for a varint */
u32 nSize; /* Size value to return */
@@ -1344,6 +1345,49 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
pPage->xParseCell(pPage, pCell, &debuginfo);
#endif
assert( pPage->childPtrSize==4 );
nSize = *pIter;
if( nSize>=0x80 ){
pEnd = &pIter[8];
nSize &= 0x7f;
do{
nSize = (nSize<<7) | (*++pIter & 0x7f);
}while( *(pIter)>=0x80 && pIter<pEnd );
}
pIter++;
testcase( nSize==pPage->maxLocal );
testcase( nSize==(u32)pPage->maxLocal+1 );
if( nSize<=pPage->maxLocal ){
nSize += (u32)(pIter - pCell);
assert( nSize>4 );
}else{
int minLocal = pPage->minLocal;
nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
testcase( nSize==pPage->maxLocal );
testcase( nSize==(u32)pPage->maxLocal+1 );
if( nSize>pPage->maxLocal ){
nSize = minLocal;
}
nSize += 4 + (u16)(pIter - pCell);
}
assert( nSize==debuginfo.nSize || CORRUPT_DB );
return (u16)nSize;
}
static u16 cellSizePtrIdxLeaf(MemPage *pPage, u8 *pCell){
u8 *pIter = pCell; /* 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
** the (CellInfo.nSize) value found by doing a full parse of the
** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
** this function verifies that this invariant is not violated. */
CellInfo debuginfo;
pPage->xParseCell(pPage, pCell, &debuginfo);
#endif
assert( pPage->childPtrSize==0 );
nSize = *pIter;
if( nSize>=0x80 ){
pEnd = &pIter[8];
@@ -1925,14 +1969,14 @@ static int decodeFlags(MemPage *pPage, int flagByte){
}else if( flagByte==(PTF_ZERODATA | PTF_LEAF) ){
pPage->intKey = 0;
pPage->intKeyLeaf = 0;
pPage->xCellSize = cellSizePtr;
pPage->xCellSize = cellSizePtrIdxLeaf;
pPage->xParseCell = btreeParseCellPtrIndex;
pPage->maxLocal = pBt->maxLocal;
pPage->minLocal = pBt->minLocal;
}else{
pPage->intKey = 0;
pPage->intKeyLeaf = 0;
pPage->xCellSize = cellSizePtr;
pPage->xCellSize = cellSizePtrIdxLeaf;
pPage->xParseCell = btreeParseCellPtrIndex;
return SQLITE_CORRUPT_PAGE(pPage);
}