/ Check-in [d861ee17]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Small size reduction and performance improvement in whereScanNext().
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1:d861ee17eb900a607de6ec3f4a5d5c24cfb834a0
User & Date: drh 2016-10-26 17:57:40
Context
2016-10-26
18:41
Small size reduction and performance enhancement in whereScanInit(). check-in: c23f5ef3 user: drh tags: trunk
17:57
Small size reduction and performance improvement in whereScanNext(). check-in: d861ee17 user: drh tags: trunk
16:05
If all branches of an OR optimize scan that is the rhs of a LEFT JOIN use the same index, set the index cursor to return NULL values if there are no matches for a row on the lhs. Fix for ticket [34a579141b2c5ac] check-in: ec9dab80 user: dan tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/where.c.

194
195
196
197
198
199
200
201
202

203
204
205



206
207
208
209
210
211
212
...
248
249
250
251
252
253
254

255
256
257
258
259
260
261
262

263
264
265
266
267
268
269
270
  int iCur;            /* The cursor on the LHS of the term */
  i16 iColumn;         /* The column on the LHS of the term.  -1 for IPK */
  Expr *pX;            /* An expression being tested */
  WhereClause *pWC;    /* Shorthand for pScan->pWC */
  WhereTerm *pTerm;    /* The term being tested */
  int k = pScan->k;    /* Where to start scanning */

  while( pScan->iEquiv<=pScan->nEquiv ){
    iCur = pScan->aiCur[pScan->iEquiv-1];

    iColumn = pScan->aiColumn[pScan->iEquiv-1];
    if( iColumn==XN_EXPR && pScan->pIdxExpr==0 ) return 0;
    while( (pWC = pScan->pWC)!=0 ){



      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
        if( pTerm->leftCursor==iCur
         && pTerm->u.leftColumn==iColumn
         && (iColumn!=XN_EXPR
             || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0)
         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin))
        ){
................................................................................
             && (pX = pTerm->pExpr->pRight)->op==TK_COLUMN
             && pX->iTable==pScan->aiCur[0]
             && pX->iColumn==pScan->aiColumn[0]
            ){
              testcase( pTerm->eOperator & WO_IS );
              continue;
            }

            pScan->k = k+1;
            return pTerm;
          }
        }
      }
      pScan->pWC = pScan->pWC->pOuter;
      k = 0;
    }

    pScan->pWC = pScan->pOrigWC;
    k = 0;
    pScan->iEquiv++;
  }
  return 0;
}

/*







|
|
>


<
>
>
>







 







>





|

|
>
|







194
195
196
197
198
199
200
201
202
203
204
205

206
207
208
209
210
211
212
213
214
215
...
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
  int iCur;            /* The cursor on the LHS of the term */
  i16 iColumn;         /* The column on the LHS of the term.  -1 for IPK */
  Expr *pX;            /* An expression being tested */
  WhereClause *pWC;    /* Shorthand for pScan->pWC */
  WhereTerm *pTerm;    /* The term being tested */
  int k = pScan->k;    /* Where to start scanning */

  assert( pScan->iEquiv<=pScan->nEquiv );
  pWC = pScan->pWC;
  while(1){
    iColumn = pScan->aiColumn[pScan->iEquiv-1];
    if( iColumn==XN_EXPR && pScan->pIdxExpr==0 ) return 0;

    iCur = pScan->aiCur[pScan->iEquiv-1];
    assert( pWC!=0 );
    do{
      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
        if( pTerm->leftCursor==iCur
         && pTerm->u.leftColumn==iColumn
         && (iColumn!=XN_EXPR
             || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0)
         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin))
        ){
................................................................................
             && (pX = pTerm->pExpr->pRight)->op==TK_COLUMN
             && pX->iTable==pScan->aiCur[0]
             && pX->iColumn==pScan->aiColumn[0]
            ){
              testcase( pTerm->eOperator & WO_IS );
              continue;
            }
            pScan->pWC = pWC;
            pScan->k = k+1;
            return pTerm;
          }
        }
      }
      pWC = pWC->pOuter;
      k = 0;
    }while( pWC!=0 );
    if( pScan->iEquiv>=pScan->nEquiv ) break;
    pWC = pScan->pOrigWC;
    k = 0;
    pScan->iEquiv++;
  }
  return 0;
}

/*