Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | Change the LEFT JOIN strength reduction optimization so that assumes that virtual table constraints can be true even if terms within the constraint are NULL. This works around dodgy virtual table implementations. Fix for ticket [fac496b61722daf2]. |
|---|---|
| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
cbb977fe1908431f3aad8e67668588b1 |
| User & Date: | drh 2018-04-03 14:04:48.605 |
| Original Comment: | Change the LEFT JOIN strength reduction optimization so that assumes that virtual table constraints can be true even if terms within the constraint are NULL. This works around dodgy virtual table implementations. |
Context
|
2018-04-03
| ||
| 14:25 | Fix the generate_series virtual table so that it correctly returns no rows if any of its constraints are NULL. Ticket [fac496b61722daf28]. (check-in: 3328e828e2 user: drh tags: trunk) | |
| 14:04 | Change the LEFT JOIN strength reduction optimization so that assumes that virtual table constraints can be true even if terms within the constraint are NULL. This works around dodgy virtual table implementations. Fix for ticket [fac496b61722daf2]. (check-in: cbb977fe19 user: drh tags: trunk) | |
|
2018-04-02
| ||
| 11:04 | Version 3.23.0 (check-in: 736b53f57f user: drh tags: trunk, release, version-3.23.0) | |
Changes
Changes to src/expr.c.
| ︙ | ︙ | |||
5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 |
return WRC_Prune;
case TK_COLUMN:
if( pWalker->u.iCur==pExpr->iTable ){
pWalker->eCode = 1;
return WRC_Abort;
}
return WRC_Prune;
default:
return WRC_Continue;
}
}
/*
** Return true (non-zero) if expression p can only be true if at least
| > > > > > > > > > > > > > > > > > > > > > | 5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067 |
return WRC_Prune;
case TK_COLUMN:
if( pWalker->u.iCur==pExpr->iTable ){
pWalker->eCode = 1;
return WRC_Abort;
}
return WRC_Prune;
/* Virtual tables are allowed to use constraints like x=NULL. So
** a term of the form x=y does not prove that y is not null if x
** is the column of a virtual table */
case TK_EQ:
case TK_NE:
case TK_LT:
case TK_LE:
case TK_GT:
case TK_GE:
testcase( pExpr->op==TK_EQ );
testcase( pExpr->op==TK_NE );
testcase( pExpr->op==TK_LT );
testcase( pExpr->op==TK_LE );
testcase( pExpr->op==TK_GT );
testcase( pExpr->op==TK_GE );
if( (pExpr->pLeft->op==TK_COLUMN && IsVirtual(pExpr->pLeft->pTab))
|| (pExpr->pRight->op==TK_COLUMN && IsVirtual(pExpr->pRight->pTab))
){
return WRC_Prune;
}
default:
return WRC_Continue;
}
}
/*
** Return true (non-zero) if expression p can only be true if at least
|
| ︙ | ︙ |