• branch=trunk inherited from [704b122e53]
• sym-trunk inherited from [704b122e53]

Changes to src/where.c

 5101      ** that do not use indices.  But this nRow reduction only happens if the        5101      ** that do not use indices.  But this nRow reduction only happens if the
 5102      ** table really is the innermost join.                                          5102      ** table really is the innermost join.
 5103      **                                                                              5103      **
 5104      ** The second loop iteration is only performed if no optimal scan               5104      ** The second loop iteration is only performed if no optimal scan
 5105      ** strategies were found by the first iteration. This second iteration          5105      ** strategies were found by the first iteration. This second iteration
 5106      ** is used to search for the lowest cost scan overall.                          5106      ** is used to search for the lowest cost scan overall.
 5107      **                                                                              5107      **
 5108      ** Previous versions of SQLite performed only the second iteration -         |  5108      ** Without the optimal scan step (the first iteration) a suboptimal
 5109      ** the next outermost loop was always that with the lowest overall           |  5109      ** plan might be chosen for queries like this:
 5110      ** cost. However, this meant that SQLite could select the wrong plan         <
 5111      ** for scripts such as the following:                                        <
 5112      **                                                                              5110      **
 5113      **   CREATE TABLE t1(a, b);                                                     5111      **   CREATE TABLE t1(a, b);
 5114      **   CREATE TABLE t2(c, d);                                                     5112      **   CREATE TABLE t2(c, d);
 5115      **   SELECT * FROM t2, t1 WHERE t2.rowid = t1.a;                                5113      **   SELECT * FROM t2, t1 WHERE t2.rowid = t1.a;
 5116      **                                                                              5114      **
 5117      ** The best strategy is to iterate through table t1 first. However it           5115      ** The best strategy is to iterate through table t1 first. However it
 5118      ** is not possible to determine this with a simple greedy algorithm.            5116      ** is not possible to determine this with a simple greedy algorithm.