SQLite

Check-in [aeb694e3f7]
Login

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

Overview
Comment:Do not attempt to use terms from the WHERE clause to drive indexes on the right table of a LEFT JOIN. Fix for ticket [4ba5abf65c5b0f9a96a7a40cd18b]
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256: aeb694e3f787f1f8b55650c17f90c197eee3f7f9b890a88f458c33e43009a082
User & Date: drh 2018-04-24 17:34:03.981
Context
2018-04-24
18:53
Fix a problem with processing "LEFT JOIN tbl ON tbl.a = ? AND (tbl.b=? OR tbl.c=?)" in cases where there are indexes on both tbl(a, b) and tbl(a, c). (check-in: ce35e39c5c user: dan tags: trunk)
17:34
Do not attempt to use terms from the WHERE clause to drive indexes on the right table of a LEFT JOIN. Fix for ticket [4ba5abf65c5b0f9a96a7a40cd18b] (check-in: aeb694e3f7 user: drh tags: trunk)
16:51
Update the expert extension test cases to account for the fact that EXPLAIN QUERY PLAN now shows the start of each trigger in its output. (check-in: 8acb42f489 user: drh tags: trunk)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/select.c.
︙
5539
5540
5541
5542
5543
5544
5545
5546

5547
5548
5549
5550
5551
5552
5553

5539
5540
5541
5542
5543
5544
5545

5546
5547
5548
5549
5550
5551
5552
5553








-
+









    /* Sometimes the code for a subquery will be generated more than
    ** once, if the subquery is part of the WHERE clause in a LEFT JOIN,
    ** for example.  In that case, do not regenerate the code to manifest
    ** a view or the co-routine to implement a view.  The first instance
    ** is sufficient, though the subroutine to manifest the view does need
    ** to be invoked again. */
    if( pItem->addrFillSub ){
    if( NEVER(pItem->addrFillSub) ){
      if( pItem->fg.viaCoroutine==0 ){
        /* The subroutine that manifests the view might be a one-time routine,
        ** or it might need to be rerun on each iteration because it
        ** encodes a correlated subquery. */
        testcase( sqlite3VdbeGetOp(v, pItem->addrFillSub)->opcode==OP_Once );
        sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub);
      }
︙
Changes to src/where.c.
︙
2416
2417
2418
2419
2420
2421
2422
2423

2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438

2416
2417
2418
2419
2420
2421
2422

2423
2424
2425
2426
2427

2428


2429
2430
2431
2432
2433
2434
2435








-
+




-

-
-








    }
    if( pTerm->prereqRight & pNew->maskSelf ) continue;

    /* Do not allow the upper bound of a LIKE optimization range constraint
    ** to mix with a lower range bound from some other source */
    if( pTerm->wtFlags & TERM_LIKEOPT && pTerm->eOperator==WO_LT ) continue;

    /* Do not allow IS constraints from the WHERE clause to be used by the
    /* Do not allow constraints from the WHERE clause to be used by the
    ** right table of a LEFT JOIN.  Only constraints in the ON clause are
    ** allowed */
    if( (pSrc->fg.jointype & JT_LEFT)!=0
     && !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
     && (eOp & (WO_IS|WO_ISNULL))!=0
    ){
      testcase( eOp & WO_IS );
      testcase( eOp & WO_ISNULL );
      continue;
    }

    if( IsUniqueIndex(pProbe) && saved_nEq==pProbe->nKeyCol-1 ){
      pBuilder->bldFlags |= SQLITE_BLDF_UNIQUE;
    }else{
      pBuilder->bldFlags |= SQLITE_BLDF_INDEXED;
︙
Changes to test/where.test.
︙
1374
1375
1376
1377
1378
1379
1380












1381
1382
1383

1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395








+
+
+
+
+
+
+
+
+
+
+
+




  CREATE INDEX t191a ON t1(a);
  CREATE INDEX t191b ON t1(b);
  CREATE TABLE t192(x INTEGER PRIMARY KEY,y INT, z INT);

  EXPLAIN QUERY PLAN
  SELECT t191.rowid FROM t192, t191 WHERE (a=y OR b=y) AND x=?1;
} {/.* sqlite_autoindex_t191_1 .* sqlite_autoindex_t191_2 .*/}

# 2018-04-24 ticket [https://www.sqlite.org/src/info/4ba5abf65c5b0f9a]
# Index on expressions leads to an incorrect answer for a LEFT JOIN
#
do_execsql_test where-20.0 {
  CREATE TABLE t201(x);
  CREATE TABLE t202(y, z);
  INSERT INTO t201 VALUES('key');
  INSERT INTO t202 VALUES('key', -1);
  CREATE INDEX t202i ON t202(y, ifnull(z, 0));
  SELECT count(*) FROM t201 LEFT JOIN t202 ON (x=y) WHERE ifnull(z, 0) >=0;
} {0}


finish_test