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Use 16-bit integers for indexing within a page in btree. Tighter

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bounds on the maximum number of cells within one page. (CVS 4796)

FossilOrigin-Name: 8fdbe4abab4e9c292111579b03471f68c1e855fb
This commit is contained in:
drh
2008-02-19 14:59:35 +00:00
parent eee4c8ca11
commit a9121e4c8e
4 changed files with 34 additions and 33 deletions
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42
src/btree.c
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@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.438 2008/01/31 14:54:44 drh Exp $
** $Id: btree.c,v 1.439 2008/02/19 14:59:35 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
@@ -622,13 +622,13 @@ void sqlite3BtreeParseCell(
** the space used by the cell pointer.
*/
#ifndef NDEBUG
static int cellSize(MemPage *pPage, int iCell){
static u16 cellSize(MemPage *pPage, int iCell){
CellInfo info;
sqlite3BtreeParseCell(pPage, iCell, &info);
return info.nSize;
}
#endif
static int cellSizePtr(MemPage *pPage, u8 *pCell){
static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
CellInfo info;
sqlite3BtreeParseCellPtr(pPage, pCell, &info);
return info.nSize;
@@ -4593,7 +4593,7 @@ static void assemblePage(
MemPage *pPage, /* The page to be assemblied */
int nCell, /* The number of cells to add to this page */
u8 **apCell, /* Pointers to cell bodies */
int *aSize /* Sizes of the cells */
u16 *aSize /* Sizes of the cells */
){
int i; /* Loop counter */
int totalSize; /* Total size of all cells */
@@ -4671,7 +4671,7 @@ static int balance_quick(MemPage *pPage, MemPage *pParent){
MemPage *pNew;
Pgno pgnoNew;
u8 *pCell;
int szCell;
u16 szCell;
CellInfo info;
BtShared *pBt = pPage->pBt;
int parentIdx = pParent->nCell; /* pParent new divider cell index */
@@ -4797,7 +4797,7 @@ static int balance_nonroot(MemPage *pPage){
int cntNew[NB+2]; /* Index in aCell[] of cell after i-th page */
int szNew[NB+2]; /* Combined size of cells place on i-th page */
u8 **apCell = 0; /* All cells begin balanced */
int *szCell; /* Local size of all cells in apCell[] */
u16 *szCell; /* Local size of all cells in apCell[] */
u8 *aCopy[NB]; /* Space for holding data of apCopy[] */
u8 *aSpace; /* Space to hold copies of dividers cells */
#ifndef SQLITE_OMIT_AUTOVACUUM
@@ -4910,25 +4910,25 @@ static int balance_nonroot(MemPage *pPage){
nMaxCells += 1+apOld[i]->nCell+apOld[i]->nOverflow;
}
/* Make nMaxCells a multiple of 2 in order to preserve 8-byte
/* Make nMaxCells a multiple of 4 in order to preserve 8-byte
** alignment */
nMaxCells = (nMaxCells + 1)&~1;
nMaxCells = (nMaxCells + 3)&~3;
/*
** Allocate space for memory structures
*/
apCell = sqlite3_malloc(
nMaxCells*sizeof(u8*) /* apCell */
+ nMaxCells*sizeof(int) /* szCell */
+ ROUND8(sizeof(MemPage))*NB /* aCopy */
+ pBt->pageSize*(5+NB) /* aSpace */
+ (ISAUTOVACUUM ? nMaxCells : 0) /* aFrom */
nMaxCells*sizeof(u8*) /* apCell */
+ nMaxCells*sizeof(u16) /* szCell */
+ (ROUND8(sizeof(MemPage))+pBt->pageSize)*NB /* aCopy */
+ pBt->pageSize*5 /* aSpace */
+ (ISAUTOVACUUM ? nMaxCells : 0) /* aFrom */
);
if( apCell==0 ){
rc = SQLITE_NOMEM;
goto balance_cleanup;
}
szCell = (int*)&apCell[nMaxCells];
szCell = (u16*)&apCell[nMaxCells];
aCopy[0] = (u8*)&szCell[nMaxCells];
assert( ((aCopy[0] - (u8*)apCell) & 7)==0 ); /* 8-byte alignment required */
for(i=1; i<NB; i++){
@@ -4997,7 +4997,7 @@ static int balance_nonroot(MemPage *pPage){
nCell++;
}
if( i<nOld-1 ){
int sz = cellSizePtr(pParent, apDiv[i]);
u16 sz = cellSizePtr(pParent, apDiv[i]);
if( leafData ){
/* With the LEAFDATA flag, pParent cells hold only INTKEYs that
** are duplicates of keys on the child pages. We need to remove
@@ -5351,16 +5351,16 @@ static int balance_shallower(MemPage *pPage){
BtShared *pBt; /* The main BTree structure */
int mxCellPerPage; /* Maximum number of cells per page */
u8 **apCell; /* All cells from pages being balanced */
int *szCell; /* Local size of all cells */
u16 *szCell; /* Local size of all cells */
assert( pPage->pParent==0 );
assert( pPage->nCell==0 );
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
pBt = pPage->pBt;
mxCellPerPage = MX_CELL(pBt);
apCell = sqlite3_malloc( mxCellPerPage*(sizeof(u8*)+sizeof(int)) );
apCell = sqlite3_malloc( mxCellPerPage*(sizeof(u8*)+sizeof(u16)) );
if( apCell==0 ) return SQLITE_NOMEM;
szCell = (int*)&apCell[mxCellPerPage];
szCell = (u16*)&apCell[mxCellPerPage];
if( pPage->leaf ){
/* The table is completely empty */
TRACE(("BALANCE: empty table %d\n", pPage->pgno));
@@ -5630,7 +5630,7 @@ int sqlite3BtreeInsert(
assert( szNew==cellSizePtr(pPage, newCell) );
assert( szNew<=MX_CELL_SIZE(pBt) );
if( loc==0 && CURSOR_VALID==pCur->eState ){
int szOld;
u16 szOld;
assert( pCur->idx>=0 && pCur->idx<pPage->nCell );
rc = sqlite3PagerWrite(pPage->pDbPage);
if( rc ){
@@ -5742,7 +5742,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
rc = sqlite3PagerWrite(leafCur.pPage->pDbPage);
}
if( rc==SQLITE_OK ){
int szNext;
u16 szNext;
TRACE(("DELETE: table=%d delete internal from %d replace from leaf %d\n",
pCur->pgnoRoot, pPage->pgno, leafCur.pPage->pgno));
dropCell(pPage, pCur->idx, cellSizePtr(pPage, pCell));
@@ -6527,7 +6527,7 @@ static int checkTreePage(
cellStart = hdr + 12 - 4*pPage->leaf;
for(i=0; i<nCell; i++){
int pc = get2byte(&data[cellStart+i*2]);
int size = cellSizePtr(pPage, &data[pc]);
u16 size = cellSizePtr(pPage, &data[pc]);
int j;
if( (pc+size-1)>=usableSize || pc<0 ){
checkAppendMsg(pCheck, 0,