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Fix the sqlite3BtreeDelete() routine so that it preserves the correct

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key even when the row being deleted is not on a leaf page.
Fix for ticket [a306e56ff68b8fa56]

FossilOrigin-Name: ca2ef8a86cf806cbbcc64db03251b1df5b2c5501
This commit is contained in:
drh
2016-04-09 17:04:05 +00:00
parent 53801efcdf
commit bfc7a8bb01
4 changed files with 51 additions and 32 deletions
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44
src/btree.c
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@@ -8140,6 +8140,28 @@ int sqlite3BtreeDelete(BtCursor *pCur, u8 flags){
pPage = pCur->apPage[iCellDepth];
pCell = findCell(pPage, iCellIdx);
/* 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;
}
}
/* If the page containing the entry to delete is not a leaf page, move
** the cursor to the largest entry in the tree that is smaller than
** the entry being deleted. This cell will replace the cell being deleted
@@ -8166,28 +8188,6 @@ int sqlite3BtreeDelete(BtCursor *pCur, u8 flags){
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. */