-C Minor\supdates\sto\scomments\sin\stest\sscripts.\s(CVS\s6714)
-D 2009-06-04T02:47:04
+C Reduce\sthe\sstack\susage\sof\sbalance_quick().\s(CVS\s6715)
+D 2009-06-04T14:46:08
F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
F src/backup.c ff50af53184a5fd7bdee4d620b5dabef74717c79
F src/bitvec.c 0ef0651714728055d43de7a4cdd95e703fac0119
F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
-F src/btree.c 708b9373d573aeb6c61899ed2fcc498a98a20b12
+F src/btree.c ca83629673417074c919b9dc4a2003d69d52de9f
F src/btree.h f70b694e8c163227369a66863b01fbff9009f323
F src/btreeInt.h df64030d632f8c8ac217ed52e8b6b3eacacb33a5
F src/build.c 20e02fd72249159ff6829009f3029d16d59cdff5
F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P bc6c2d894b711361808a19b673803186d3a28369
-R 9dd9dd8b1b74bf1fededc820a0a5d128
-U shane
-Z 1d673d399a0b5a991b96f6d097baa1ce
+P 453ff88f73a01a54ff464563effdb63014b1972c
+R 10cf14b6134b53081d5b29cc87d78754
+U danielk1977
+Z ea544126f0e51edd041f5bf4bda237c8
** May you share freely, never taking more than you give.
**
*************************************************************************
-** $Id: btree.c,v 1.613 2009/06/04 00:11:56 drh Exp $
+** $Id: btree.c,v 1.614 2009/06/04 14:46:08 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
}
#endif
-
/* Compute the total free space on the page */
pc = get2byte(&data[hdr+1]);
nFree = data[hdr+7] + top;
** which is also the right-most entry on the page.
*/
static int balance_quick(BtCursor *pCur){
- int rc;
- MemPage *pNew = 0;
- Pgno pgnoNew;
- u8 *pCell;
- u16 szCell;
- CellInfo info;
- MemPage *pPage = pCur->apPage[pCur->iPage];
- MemPage *pParent = pCur->apPage[pCur->iPage-1];
- BtShared *pBt = pPage->pBt;
- int parentIdx = pParent->nCell; /* pParent new divider cell index */
- int parentSize; /* Size of new divider cell */
- u8 parentCell[64]; /* Space for the new divider cell */
+ MemPage *const pPage = pCur->apPage[pCur->iPage];
+ BtShared *const pBt = pCur->pBt;
+ MemPage *pNew = 0; /* Newly allocated page */
+ int rc; /* Return Code */
+ Pgno pgnoNew; /* Page number of pNew */
assert( sqlite3_mutex_held(pPage->pBt->mutex) );
+ assert( pPage->nCell>0 );
- /* Allocate a new page. Insert the overflow cell from pPage
- ** into it. Then remove the overflow cell from pPage.
- */
+ /* Allocate a new page. This page will become the right-sibling of pPage */
rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
+
if( rc==SQLITE_OK ){
- pCell = pPage->aOvfl[0].pCell;
- szCell = cellSizePtr(pPage, pCell);
+ /* The parentCell buffer is used to store a temporary copy of the divider
+ ** cell that will be inserted into pParent. Such a cell consists of a 4
+ ** byte page number followed by a variable length integer. In other
+ ** words, at most 13 bytes. Hence the parentCell buffer must be at
+ ** least 13 bytes in size.
+ */
+ MemPage * const pParent = pCur->apPage[pCur->iPage-1];
+ u8 parentCell[13];
+ u8 *pOut = &parentCell[4];
+ u8 *pCell = pPage->aOvfl[0].pCell;
+ u16 szCell = cellSizePtr(pPage, pCell);
+ u8 *pStop;
+
assert( sqlite3PagerIswriteable(pNew->pDbPage) );
zeroPage(pNew, pPage->aData[0]);
assemblePage(pNew, 1, &pCell, &szCell);
pPage->nOverflow = 0;
- /* pPage is currently the right-child of pParent. Change this
- ** so that the right-child is the new page allocated above and
- ** pPage is the next-to-right child.
- **
- ** Ignore the return value of the call to fillInCell(). fillInCell()
- ** may only return other than SQLITE_OK if it is required to allocate
- ** one or more overflow pages. Since an internal table B-Tree cell
- ** may never spill over onto an overflow page (it is a maximum of
- ** 13 bytes in size), it is not neccessary to check the return code.
+ /* Create a divider cell to insert into pParent. The divider cell
+ ** consists of a 4-byte page number (the page number of pPage) and
+ ** a variable length key value (which must be the same value as the
+ ** largest key on pPage).
**
- ** Similarly, the insertCell() function cannot fail if the page
- ** being inserted into is already writable and the cell does not
- ** contain an overflow pointer. So ignore this return code too.
+ ** To find the largest key value on pPage, first find the right-most
+ ** cell on pPage. The first two fields of this cell are the
+ ** record-length (a variable length integer at most 32-bits in size)
+ ** and the key value (a variable length integer, may have any value).
+ ** The first of the while(...) loops below skips over the record-length
+ ** field. The second while(...) loop copies the key value from the
+ ** cell on pPage into the parentCell buffer.
*/
- assert( pPage->nCell>0 );
+ put4byte(parentCell, pPage->pgno);
pCell = findCell(pPage, pPage->nCell-1);
- sqlite3BtreeParseCellPtr(pPage, pCell, &info);
- fillInCell(pParent, parentCell, 0, info.nKey, 0, 0, 0, &parentSize);
- assert( parentSize<64 );
- assert( sqlite3PagerIswriteable(pParent->pDbPage) );
- insertCell(pParent, parentIdx, parentCell, parentSize, 0, 4);
- put4byte(findOverflowCell(pParent,parentIdx), pPage->pgno);
+ pStop = &pCell[9];
+ while( (*(pCell++)&0x80) && pCell<pStop );
+ pStop = &pCell[9];
+ while( ((*(pOut++) = *(pCell++))&0x80) && pCell<pStop );
+
+ /* Insert the new divider cell into pParent */
+ insertCell(pParent, pParent->nCell, parentCell, pOut-parentCell, 0, 0);
+
+ /* Set the right-child pointer of pParent to point to the new page. */
put4byte(&pParent->aData[pParent->hdrOffset+8], pgnoNew);
/* If this is an auto-vacuum database, update the pointer map
szNew[i-1] = szLeft;
}
- /* Either we found one or more cells (cntnew[0])>0) or we are the
+ /* Either we found one or more cells (cntnew[0])>0) or pPage is
** a virtual root page. A virtual root page is when the real root
** page is page 1 and we are the only child of that page.
*/
projects / thirdparty / sqlite.git / commitdiff
