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Do not clear the MemPage.nFree variable when insertCell() adds an overflow cell to a page. Not doing this means balance_quick() can avoid a call to sqlite3BtreeInitPage(). (CVS 6732)

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FossilOrigin-Name: 8f1c1f61f7bc5270212725cf0a056872df983f49
This commit is contained in:
danielk1977
2009-06-09 09:41:00 +00:00
parent 254993e2e5
commit 6067a9bbfe
3 changed files with 17 additions and 42 deletions
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43
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 1.620 2009/06/08 14:49:46 danielk1977 Exp $
** $Id: btree.c,v 1.621 2009/06/09 09:41:00 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
@@ -5089,7 +5089,6 @@ static int insertCell(
assert( j<(int)(sizeof(pPage->aOvfl)/sizeof(pPage->aOvfl[0])) );
pPage->aOvfl[j].pCell = pCell;
pPage->aOvfl[j].idx = (u16)i;
pPage->nFree = 0;
}else{
int rc = sqlite3PagerWrite(pPage->pDbPage);
if( rc!=SQLITE_OK ){
@@ -5292,23 +5291,6 @@ static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
/* Release the reference to the new page. */
releasePage(pNew);
/* At this point the pPage->nFree variable is not set correctly with
** respect to the content of the page (because it was set to 0 by
** insertCell). So call sqlite3BtreeInitPage() to make sure it is
** correct.
**
** This has to be done even if an error will be returned. Normally, if
** an error occurs during tree balancing, the contents of MemPage are
** not important, as they will be recalculated when the page is rolled
** back. But here, in balance_quick(), it is possible that pPage has
** not yet been marked dirty or written into the journal file. Therefore
** it will not be rolled back and so it is important to make sure that
** the page data and contents of MemPage are consistent.
*/
pPage->isInit = 0;
sqlite3BtreeInitPage(pPage);
assert( pPage->nOverflow==0 );
}
return rc;
@@ -5341,10 +5323,10 @@ static int balance_quick(MemPage *pParent, MemPage *pPage, u8 *pSpace){
** is called recursively on the parent.
**
** If this routine fails for any reason, it might leave the database
** in a corrupted state. So if this routine fails, the database should
** in a corrupted state. So if this routine fails, the database should
** be rolled back.
*/
static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aSpace2){
static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aOvflSpace){
BtShared *pBt; /* The whole database */
int nCell = 0; /* Number of cells in apCell[] */
int nMaxCells = 0; /* Allocated size of apCell, szCell, aFrom. */
@@ -5359,7 +5341,7 @@ static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aSpace2){
int pageFlags; /* Value of pPage->aData[0] */
int subtotal; /* Subtotal of bytes in cells on one page */
int iSpace1 = 0; /* First unused byte of aSpace1[] */
int iSpace2 = 0; /* First unused byte of aSpace2[] */
int iOvflSpace = 0; /* First unused byte of aOvflSpace[] */
int szScratch; /* Size of scratch memory requested */
MemPage *apOld[NB]; /* pPage and up to two siblings */
Pgno pgnoOld[NB]; /* Page numbers for each page in apOld[] */
@@ -5426,7 +5408,7 @@ static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aSpace2){
+ pBt->pageSize /* aSpace1 */
+ (ISAUTOVACUUM ? nMaxCells : 0); /* aFrom */
apCell = sqlite3ScratchMalloc( szScratch );
if( apCell==0 ){
if( apCell==0 || aOvflSpace==0 ){
rc = SQLITE_NOMEM;
goto balance_cleanup;
}
@@ -5442,11 +5424,6 @@ static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aSpace2){
if( ISAUTOVACUUM ){
aFrom = &aSpace1[pBt->pageSize];
}
/* aSpace2 = sqlite3PageMalloc(pBt->pageSize); */
if( aSpace2==0 ){
rc = SQLITE_NOMEM;
goto balance_cleanup;
}
/*
** Make copies of the content of pPage and its siblings into aOld[].
@@ -5736,7 +5713,7 @@ static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aSpace2){
assert( j<nMaxCells );
pCell = apCell[j];
sz = szCell[j] + leafCorrection;
pTemp = &aSpace2[iSpace2];
pTemp = &aOvflSpace[iOvflSpace];
if( !pNew->leaf ){
memcpy(&pNew->aData[8], pCell, 4);
if( ISAUTOVACUUM
@@ -5780,9 +5757,9 @@ static int balance_nonroot(MemPage *pParent, int iParentIdx, u8 *aSpace2){
sz = cellSizePtr(pParent, pCell);
}
}
iSpace2 += sz;
iOvflSpace += sz;
assert( sz<=pBt->pageSize/4 );
assert( iSpace2<=pBt->pageSize );
assert( iOvflSpace<=pBt->pageSize );
rc = insertCell(pParent, nxDiv, pCell, sz, pTemp, 4);
if( rc!=SQLITE_OK ) goto balance_cleanup;
assert( sqlite3PagerIswriteable(pParent->pDbPage) );
@@ -5915,7 +5892,6 @@ static int copyNodeContent(MemPage *pFrom, MemPage *pTo){
** shallower by one level.
*/
static int balance_shallower(MemPage *pRoot){
/* The root page is empty but has one child. Transfer the
** information from that one child into the root page if it
** will fit. This reduces the depth of the tree by one.
@@ -5944,7 +5920,7 @@ static int balance_shallower(MemPage *pRoot){
if( rc==SQLITE_OK ){
if( pChild->nFree>=hdr ){
if( hdr ){
rc = defragmentPage(pChild);
rc = defragmentPage(pChild);
}
if( rc==SQLITE_OK ){
rc = copyNodeContent(pChild, pRoot);
@@ -6015,7 +5991,6 @@ static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
/* Copy the overflow cells from pRoot to pChild */
memcpy(pChild->aOvfl, pRoot->aOvfl, pRoot->nOverflow*sizeof(pRoot->aOvfl[0]));
pChild->nOverflow = pRoot->nOverflow;
pChild->nFree = 0;
/* Zero the contents of pRoot. Then install pChild as the right-child. */
zeroPage(pRoot, pChild->aData[0] & ~PTF_LEAF);