Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | When constructing automatic indices do not include the same column more than once. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | experimental |
| Files: | files | file ages | folders |
| SHA1: |
d067d9f7a9138e026c1018361127e343 |
| User & Date: | drh 2010-04-08 00:40:15.000 |
| Original Comment: | When constructing automatic indices do not include the same column more than once. |
Context
|
2010-04-08
| ||
| 01:16 | Merge automatic index changes into the trunk. (check-in: bf7b8d8636 user: drh tags: trunk) | |
| 00:40 | When constructing automatic indices do not include the same column more than once. (Closed-Leaf check-in: d067d9f7a9 user: drh tags: experimental) | |
|
2010-04-07
| ||
| 20:32 | Pull over the latest changes from the trunk. (check-in: e388fe8be8 user: drh tags: experimental) | |
Changes
Changes to src/where.c.
| ︙ | ︙ | |||
1769 1770 1771 1772 1773 1774 1775 |
nColumn = 0;
pTable = pSrc->pTab;
pWCEnd = &pWC->a[pWC->nTerm];
idxCols = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
int iCol = pTerm->u.leftColumn;
| > | | > > | | 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 |
nColumn = 0;
pTable = pSrc->pTab;
pWCEnd = &pWC->a[pWC->nTerm];
idxCols = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
int iCol = pTerm->u.leftColumn;
Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;
if( (idxCols & cMask)==0 ){
nColumn++;
idxCols |= cMask;
}
}
}
assert( nColumn>0 );
pLevel->plan.nEq = nColumn;
/* Count the number of additional columns needed to create a
** covering index. A "covering index" is an index that contains all
** columns that are needed by the query. With a covering index, the
** original table never needs to be accessed. Automatic indices must
** be a covering index because the index will not be updated if the
** original table changes and the index and table cannot both be used
** if they go out of sync.
*/
extraCols = pSrc->colUsed & (~idxCols | (((Bitmask)1)<<(BMS-1)));
mxBitCol = (pTable->nCol >= BMS-1) ? BMS-1 : pTable->nCol;
for(i=0; i<mxBitCol; i++){
if( extraCols & (1<<i) ) nColumn++;
}
if( pSrc->colUsed & (((Bitmask)1)<<(BMS-1)) ){
nColumn += pTable->nCol - BMS + 1;
}
|
| ︙ | ︙ | |||
1809 1810 1811 1812 1813 1814 1815 1816 1817 |
pIdx->azColl = (char**)&pIdx[1];
pIdx->aiColumn = (int*)&pIdx->azColl[nColumn];
pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nColumn];
pIdx->zName = "auto-index";
pIdx->nColumn = nColumn;
pIdx->pTable = pTable;
n = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
| > > > > | > | | | | > | 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 |
pIdx->azColl = (char**)&pIdx[1];
pIdx->aiColumn = (int*)&pIdx->azColl[nColumn];
pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nColumn];
pIdx->zName = "auto-index";
pIdx->nColumn = nColumn;
pIdx->pTable = pTable;
n = 0;
idxCols = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
int iCol = pTerm->u.leftColumn;
Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;
if( (idxCols & cMask)==0 ){
Expr *pX = pTerm->pExpr;
idxCols |= cMask;
pIdx->aiColumn[n] = pTerm->u.leftColumn;
pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
pIdx->azColl[n] = pColl->zName;
n++;
}
}
}
assert( n==pLevel->plan.nEq );
/* Add additional columns needed to make the automatic index into
** a covering index */
for(i=0; i<mxBitCol; i++){
|
| ︙ | ︙ |