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Overview
| Comment: | Clarify the computation of compatible isOrdered by in the plan solver of the query planner. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | query-planner-fix |
| Files: | files | file ages | folders |
| SHA1: | b5e8fd575a80334160de0aac8084ed5c |
| User & Date: | drh 2014-08-07 20:37:01 |
Context
|
2014-08-07
| ||
| 20:42 | When the estimated sorting cost overwhelms the estimated lookup cost, ensure that lookup costs are still taken into account when selecting a lookup algorithm. check-in: 2af630c5 user: drh tags: trunk | |
| 20:37 | Clarify the computation of compatible isOrdered by in the plan solver of the query planner. Closed-Leaf check-in: b5e8fd57 user: drh tags: query-planner-fix | |
| 20:25 | Remove the extraneous debugging printf() from the previous check-in. check-in: 8f04d2c0 user: drh tags: query-planner-fix | |
Changes
Changes to src/where.c.
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}
/* Check to see if pWLoop should be added to the set of
** mxChoice best-so-far paths.
**
** First look for an existing path among best-so-far paths
** that covers the same set of loops and has the same isOrdered
** setting as the current path candidate.
*/
for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
if( pTo->maskLoop==maskNew
&& ((pTo->isOrdered^isOrdered)&80)==0
){
testcase( jj==nTo-1 );
break;
}
}
if( jj>=nTo ){
/* None of the existing best-so-far paths match the candidate. */
|
> > > > | |
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}
/* Check to see if pWLoop should be added to the set of
** mxChoice best-so-far paths.
**
** First look for an existing path among best-so-far paths
** that covers the same set of loops and has the same isOrdered
** setting as the current path candidate.
**
** The term "((pTo->isOrdered^isOrdered)&0x80)==0" is equivalent
** to (pTo->isOrdered==(-1))==(isOrdered==(-1))" for the range
** of legal values for isOrdered, -1..64.
*/
for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
if( pTo->maskLoop==maskNew
&& ((pTo->isOrdered^isOrdered)&0x80)==0
){
testcase( jj==nTo-1 );
break;
}
}
if( jj>=nTo ){
/* None of the existing best-so-far paths match the candidate. */
|