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-rw-r--r--src/btree.c118
1 files changed, 63 insertions, 55 deletions
diff --git a/src/btree.c b/src/btree.c
index 252a433bd..e128d7dbc 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -9,7 +9,7 @@
** May you share freely, never taking more than you give.
**
*************************************************************************
-** $Id: btree.c,v 1.107 2004/05/02 21:12:19 drh Exp $
+** $Id: btree.c,v 1.108 2004/05/03 19:49:33 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
@@ -467,7 +467,7 @@ static int allocateSpace(MemPage *pPage, int nByte){
if( nByte<4 ) nByte = 4;
if( pPage->nFree<nByte || pPage->isOverfull ) return 0;
hdr = pPage->hdrOffset;
- if( data[hdr+5]>=252 ){
+ if( data[hdr+5]>=60 ){
defragmentPage(pPage);
}
addr = hdr+1;
@@ -1098,7 +1098,7 @@ int sqlite3BtreeBeginStmt(Btree *pBt){
if( !pBt->inTrans || pBt->inStmt ){
return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
}
- rc = pBt->readOnly ? SQLITE_OK : sqlitepager_ckpt_begin(pBt->pPager);
+ rc = pBt->readOnly ? SQLITE_OK : sqlitepager_stmt_begin(pBt->pPager);
pBt->inStmt = 1;
return rc;
}
@@ -1111,7 +1111,7 @@ int sqlite3BtreeBeginStmt(Btree *pBt){
int sqlite3BtreeCommitStmt(Btree *pBt){
int rc;
if( pBt->inStmt && !pBt->readOnly ){
- rc = sqlitepager_ckpt_commit(pBt->pPager);
+ rc = sqlitepager_stmt_commit(pBt->pPager);
}else{
rc = SQLITE_OK;
}
@@ -1131,7 +1131,7 @@ int sqlite3BtreeRollbackStmt(Btree *pBt){
int rc;
BtCursor *pCur;
if( pBt->inStmt==0 || pBt->readOnly ) return SQLITE_OK;
- rc = sqlitepager_ckpt_rollback(pBt->pPager);
+ rc = sqlitepager_stmt_rollback(pBt->pPager);
for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
MemPage *pPage = pCur->pPage;
if( pPage && !pPage->isInit ){
@@ -1991,7 +1991,7 @@ static int allocatePage(Btree *pBt, MemPage **ppPage, Pgno *pPgno, Pgno nearby){
pPage1 = pBt->pPage1;
n = get4byte(&pPage1->aData[36]);
if( n>0 ){
- /* There exists pages on the freelist. Reuse one of those pages. */
+ /* There are pages on the freelist. Reuse one of those pages. */
MemPage *pTrunk;
rc = sqlitepager_write(pPage1->aData);
if( rc ) return rc;
@@ -2133,28 +2133,16 @@ static int clearCell(MemPage *pPage, unsigned char *pCell){
}
/*
-** Compute the number of bytes required by a cell header. Fill in
-** the nData and nKey values of the header that pHeader points to.
-*/
-static int makeCellHeader(
- MemPage *pPage, /* The page that will contain the cell */
- u64 nKey, /* Size of key, or the key value if intKey */
- int nData, /* Size of data. Ignored for zerodata */
- unsigned char *pHeader /* Write header bytes here */
-){
- int n = 2;
- if( !pPage->leaf ) n += 4;
- if( !pPage->zeroData ){
- n += putVarint(&pHeader[n], nData);
- }
- n += putVarint(&pHeader[n], nKey);
- return n;
-}
-
-/*
-** Fill in the payload section of a cell into the space provided. If
-** the payload will not completely fit in the cell, allocate additional
-** overflow pages and fill them in.
+** Create the byte sequence used to represent a cell on page pPage
+** and write that byte sequence into pCell[]. Overflow pages are
+** allocated and filled in as necessary. The calling procedure
+** is responsible for making sure sufficient space has been allocated
+** for pCell[].
+**
+** Note that pCell does not necessary need to point to the pPage->aData
+** area. pCell might point to some temporary storage. The cell will
+** be constructed in this temporary area then copied into pPage->aData
+** later.
*/
static int fillInCell(
MemPage *pPage, /* The page that contains the cell */
@@ -2174,12 +2162,25 @@ static int fillInCell(
Pgno pgnoOvfl = 0;
int nHeader;
- nHeader = makeCellHeader(pPage, pCell, nKey, nData);
+ /* Fill in the header. */
+ nHeader = 2;
+ if( !pPage->leaf ){
+ nHeader += 4;
+ }
+ if( !pPage->zeroData ){
+ nHeader += putVarint(&pCell[nHeader], nData);
+ }
+ nHeader += putVarint(&pCell[nHeader], nKey);
+
+ /* Fill in the payload */
+ if( pPage->zeroData ){
+ nData = 0;
+ }
nPayload = nData;
if( pPage->intKey ){
pSrc = pData;
nSrc = nData;
- nSrc2 = 0;
+ nData = 0;
}else{
nPayload += nKey;
pSrc = pKey;
@@ -2354,10 +2355,12 @@ static void relinkCellList(MemPage *pPage){
}
/*
-** Make a copy of the contents of pFrom into pTo. The pFrom->aCell[]
+** Move the content of the page at pFrom over to pTo. The pFrom->aCell[]
** pointers that point into pFrom->aData[] must be adjusted to point
** into pTo->aData[] instead. But some pFrom->aCell[] entries might
** not point to pFrom->aData[]. Those are unchanged.
+**
+** Over this operation completes, the meta data for pFrom is zeroed.
*/
static void copyPage(MemPage *pTo, MemPage *pFrom){
uptr from, to;
@@ -2368,23 +2371,18 @@ static void copyPage(MemPage *pTo, MemPage *pFrom){
assert( pTo->hdrOffset==0 );
ofst = pFrom->hdrOffset;
pageSize = pTo->pBt->pageSize;
- memcpy(pTo->aData, &pFrom->aData[ofst], pageSize - ofst);
- pTo->pParent = 0;
- pTo->isInit = 1;
- resizeCellArray(pTo, pFrom->nCell);
- pTo->nCell = pFrom->nCell;
- pTo->nFree = pFrom->nFree + ofst;
+ sqliteFree(pTo->aCell);
+ memcpy(pTo->aData, &pFrom->aData[ofst], pageSize - ofst + sizeof(MemPage));
+ memset(pFrom, 0, sizeof(MemPage));
assert( pTo->aData[5]<155 );
pTo->aData[5] += ofst;
pTo->isOverfull = pFrom->isOverfull;
to = Addr(pTo->aData);
- from = Addr(pFrom->aData);
+ from = Addr(&pFrom->aData[ofst]);
for(i=0; i<pTo->nCell; i++){
- uptr x = Addr(pFrom->aCell[i]);
- if( x>from && x<from+pageSize ){
+ uptr x = Addr(pTo->aCell[i]);
+ if( x>from && x<from+pageSize-ofst ){
*((uptr*)&pTo->aCell[i]) = x + to - from;
- }else{
- pTo->aCell[i] = pFrom->aCell[i];
}
}
}
@@ -2451,6 +2449,9 @@ static int balance(MemPage *pPage){
int nxDiv; /* Next divider slot in pParent->apCell[] */
int rc; /* The return code */
int iCur; /* apCell[iCur] is the cell of the cursor */
+ int leafCorrection; /* 4 if pPage is a leaf. 0 if not */
+ int usableSpace; /* Bytes in pPage beyond the header */
+ int pageFlags; /* Value of pPage->aData[0] */
MemPage *pOldCurPage; /* The cursor originally points to this page */
int subtotal; /* Subtotal of bytes in cells on one page */
MemPage *apOld[NB]; /* pPage and up to two siblings */
@@ -2630,6 +2631,8 @@ static int balance(MemPage *pPage){
rc = initPage(apOld[i], pParent);
if( rc ) goto balance_cleanup;
apOld[i]->idxParent = k;
+ apCopy[i] = 0;
+ assert( i==nOld );
nOld++;
}
@@ -2844,12 +2847,16 @@ static int balance(MemPage *pPage){
*/
balance_cleanup:
for(i=0; i<nOld; i++){
- if( apOld[i]!=0 ) sqlitepager_unref(apOld[i]->aData);
+ releasePage(apOld[i]);
+ if( apCopy[i] ){
+ releasePage(apCopy[i]->pParent);
+ sqliteFree(apCopy[i]->aCell);
+ }
}
for(i=0; i<nNew; i++){
- sqlitepager_unref(apNew[i]->aData);
+ releasePage(apNew[i]);
}
- sqlitepager_unref(pParent->aData);
+ releasePage(pParent);
return rc;
}
@@ -2874,8 +2881,9 @@ static int checkReadLocks(BtCursor *pCur){
for(p=pCur->pShared; p!=pCur; p=p->pShared){
assert( p );
assert( p->pgnoRoot==pCur->pgnoRoot );
+ assert( p->pPage->pgno==sqlitepager_pagenumber(p->pPage->aData);
if( p->wrFlag==0 ) return SQLITE_LOCKED;
- if( sqlitepager_pagenumber(p->pPage)!=p->pgnoRoot ){
+ if( p->pPage->pgno!=p->pgnoRoot ){
moveToRoot(p);
}
}
@@ -2885,7 +2893,7 @@ static int checkReadLocks(BtCursor *pCur){
/*
** Insert a new record into the BTree. The key is given by (pKey,nKey)
** and the data is given by (pData,nData). The cursor is used only to
-** define what database the record should be inserted into. The cursor
+** define what table the record should be inserted into. The cursor
** is left pointing at a random location.
**
** For an INTKEY table, only the nKey value of the key is used. pKey is
@@ -2920,9 +2928,8 @@ int sqlite3BtreeInsert(
rc = sqlite3BtreeMoveto(pCur, pKey, nKey, &loc);
if( rc ) return rc;
pPage = pCur->pPage;
- assert( nData==0 || pPage->zeroData!=0 );
assert( pPage->isInit );
- rc = sqlitepager_write(pPage);
+ rc = sqlitepager_write(pPage->aData);
if( rc ) return rc;
rc = fillInCell(pPage, &newCell, pKey, nKey, pData, nData, &szNew);
if( rc ) return rc;
@@ -2982,7 +2989,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
if( checkReadLocks(pCur) ){
return SQLITE_LOCKED; /* The table pCur points to has a read lock */
}
- rc = sqlitepager_write(pPage);
+ rc = sqlitepager_write(pPage->aData);
if( rc ) return rc;
pCell = pPage->aCell[pCur->idx];
if( !pPage->leaf ){
@@ -3007,7 +3014,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
if( rc!=SQLITE_NOMEM ) rc = SQLITE_CORRUPT;
return rc;
}
- rc = sqlitepager_write(leafCur.pPage);
+ rc = sqlitepager_write(leafCur.pPage->aData);
if( rc ) return rc;
dropCell(pPage, pCur->idx, cellSize(pPage, pCell));
pNext = leafCur.pPage->aCell[leafCur.idx];
@@ -3052,7 +3059,7 @@ int sqlite3BtreeCreateTable(Btree *pBt, int *piTable, int flags){
if( rc ) return rc;
assert( sqlitepager_iswriteable(pRoot->aData) );
zeroPage(pBt, pRoot);
- sqlitepager_unref(pRoot);
+ sqlitepager_unref(pRoot->aData);
*piTable = (int)pgnoRoot;
return SQLITE_OK;
}
@@ -3276,7 +3283,7 @@ static int fileBtreePageDump(Btree *pBt, int pgno, int recursive){
}
fileBtreePageDump(pBt, get4byte(&pPage->aData[hdrOffset+6]), 1);
}
- sqlitepager_unref(pPage);
+ sqlitepager_unref(pPage->aData);
return SQLITE_OK;
}
#endif
@@ -3302,7 +3309,8 @@ static int fileBtreeCursorDump(BtCursor *pCur, int *aResult){
MemPage *pPage = pCur->pPage;
Btree *pBt = pCur->pBt;
assert( pPage->isInit );
- aResult[0] = sqlitepager_pagenumber(pPage);
+ aResult[0] = sqlitepager_pagenumber(pPage->aData);
+ assert( aResult[0]==pPage->pgno );
aResult[1] = pCur->idx;
aResult[2] = pPage->nCell;
if( pCur->idx>=0 && pCur->idx<pPage->nCell ){
@@ -3492,7 +3500,7 @@ static int checkTreePage(
if( (rc = initPage(pPage, pParent))!=0 ){
sprintf(zMsg, "initPage() returns error code %d", rc);
checkAppendMsg(pCheck, zContext, zMsg);
- sqlitepager_unref(pPage);
+ releasePage(pPage);
return 0;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-22 06:30:44 +0000