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Merge enhancements from trunk.

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FossilOrigin-Name: 66fe06832614010d3156d7b21a760af9957018cc
This commit is contained in:
drh
2015-09-15 17:31:47 +00:00
parent 163c29c5f3 6609bab24d
commit 81966bea22
105 changed files with 5114 additions and 2026 deletions
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126
src/btree.c
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@@ -591,6 +591,49 @@ static void btreeReleaseAllCursorPages(BtCursor *pCur){
pCur->iPage = -1;
}
/*
** The cursor passed as the only argument must point to a valid entry
** when this function is called (i.e. have eState==CURSOR_VALID). This
** function saves the current cursor key in variables pCur->nKey and
** pCur->pKey. SQLITE_OK is returned if successful or an SQLite error
** code otherwise.
**
** If the cursor is open on an intkey table, then the integer key
** (the rowid) is stored in pCur->nKey and pCur->pKey is left set to
** NULL. If the cursor is open on a non-intkey table, then pCur->pKey is
** set to point to a malloced buffer pCur->nKey bytes in size containing
** the key.
*/
static int saveCursorKey(BtCursor *pCur){
int rc;
assert( CURSOR_VALID==pCur->eState );
assert( 0==pCur->pKey );
assert( cursorHoldsMutex(pCur) );
rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);
assert( rc==SQLITE_OK ); /* KeySize() cannot fail */
/* If this is an intKey table, then the above call to BtreeKeySize()
** stores the integer key in pCur->nKey. In this case this value is
** all that is required. Otherwise, if pCur is not open on an intKey
** table, then malloc space for and store the pCur->nKey bytes of key
** data. */
if( 0==pCur->curIntKey ){
void *pKey = sqlite3Malloc( pCur->nKey );
if( pKey ){
rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
if( rc==SQLITE_OK ){
pCur->pKey = pKey;
}else{
sqlite3_free(pKey);
}
}else{
rc = SQLITE_NOMEM;
}
}
assert( !pCur->curIntKey || !pCur->pKey );
return rc;
}
/*
** Save the current cursor position in the variables BtCursor.nKey
@@ -611,30 +654,8 @@ static int saveCursorPosition(BtCursor *pCur){
}else{
pCur->skipNext = 0;
}
rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);
assert( rc==SQLITE_OK ); /* KeySize() cannot fail */
/* If this is an intKey table, then the above call to BtreeKeySize()
** stores the integer key in pCur->nKey. In this case this value is
** all that is required. Otherwise, if pCur is not open on an intKey
** table, then malloc space for and store the pCur->nKey bytes of key
** data.
*/
if( 0==pCur->curIntKey ){
void *pKey = sqlite3Malloc( pCur->nKey );
if( pKey ){
rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
if( rc==SQLITE_OK ){
pCur->pKey = pKey;
}else{
sqlite3_free(pKey);
}
}else{
rc = SQLITE_NOMEM;
}
}
assert( !pCur->curIntKey || !pCur->pKey );
rc = saveCursorKey(pCur);
if( rc==SQLITE_OK ){
btreeReleaseAllCursorPages(pCur);
pCur->eState = CURSOR_REQUIRESEEK;
@@ -8047,10 +8068,15 @@ end_insert:
}
/*
** Delete the entry that the cursor is pointing to. The cursor
** is left pointing at an arbitrary location.
** Delete the entry that the cursor is pointing to.
**
** If the second parameter is zero, then the cursor is left pointing at an
** arbitrary location after the delete. If it is non-zero, then the cursor
** is left in a state such that the next call to BtreeNext() or BtreePrev()
** moves it to the same row as it would if the call to BtreeDelete() had
** been omitted.
*/
int sqlite3BtreeDelete(BtCursor *pCur){
int sqlite3BtreeDelete(BtCursor *pCur, int bPreserve){
Btree *p = pCur->pBtree;
BtShared *pBt = p->pBt;
int rc; /* Return code */
@@ -8059,6 +8085,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
int iCellIdx; /* Index of cell to delete */
int iCellDepth; /* Depth of node containing pCell */
u16 szCell; /* Size of the cell being deleted */
int bSkipnext = 0; /* Leaf cursor in SKIPNEXT state */
assert( cursorHoldsMutex(pCur) );
assert( pBt->inTransaction==TRANS_WRITE );
@@ -8088,10 +8115,7 @@ int sqlite3BtreeDelete(BtCursor *pCur){
}
/* Save the positions of any other cursors open on this table before
** making any modifications. Make the page containing the entry to be
** deleted writable. Then free any overflow pages associated with the
** entry and finally remove the cell itself from within the page.
*/
** making any modifications. */
if( pCur->curFlags & BTCF_Multiple ){
rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
if( rc ) return rc;
@@ -8103,6 +8127,31 @@ int sqlite3BtreeDelete(BtCursor *pCur){
invalidateIncrblobCursors(p, pCur->info.nKey, 0);
}
/* If the bPreserve flag is set to true, then the cursor position must
** be preserved following this delete operation. If the current delete
** will cause a b-tree rebalance, then this is done by saving the cursor
** key and leaving the cursor in CURSOR_REQUIRESEEK state before
** returning.
**
** Or, if the current delete will not cause a rebalance, then the cursor
** will be left in CURSOR_SKIPNEXT state pointing to the entry immediately
** before or after the deleted entry. In this case set bSkipnext to true. */
if( bPreserve ){
if( !pPage->leaf
|| (pPage->nFree+cellSizePtr(pPage,pCell)+2)>(int)(pBt->usableSize*2/3)
){
/* A b-tree rebalance will be required after deleting this entry.
** Save the cursor key. */
rc = saveCursorKey(pCur);
if( rc ) return rc;
}else{
bSkipnext = 1;
}
}
/* Make the page containing the entry to be deleted writable. Then free any
** overflow pages associated with the entry and finally remove the cell
** itself from within the page. */
rc = sqlite3PagerWrite(pPage->pDbPage);
if( rc ) return rc;
rc = clearCell(pPage, pCell, &szCell);
@@ -8156,7 +8205,22 @@ int sqlite3BtreeDelete(BtCursor *pCur){
}
if( rc==SQLITE_OK ){
moveToRoot(pCur);
if( bSkipnext ){
assert( bPreserve && pCur->iPage==iCellDepth );
assert( pPage->nCell>0 && iCellIdx<=pPage->nCell );
pCur->eState = CURSOR_SKIPNEXT;
if( iCellIdx>=pPage->nCell ){
pCur->skipNext = -1;
pCur->aiIdx[iCellDepth] = pPage->nCell-1;
}else{
pCur->skipNext = 1;
}
}else{
rc = moveToRoot(pCur);
if( bPreserve ){
pCur->eState = CURSOR_REQUIRESEEK;
}
}
}
return rc;
}