github.com/jdgcs/sqlite3@v1.12.1-0.20210908114423-bc5f96e4dd51/testdata/tcl/tkt3757.test (about)

     1  # 2009 March 28
     2  #
     3  # The author disclaims copyright to this source code.  In place of
     4  # a legal notice, here is a blessing:
     5  #
     6  #    May you do good and not evil.
     7  #    May you find forgiveness for yourself and forgive others.
     8  #    May you share freely, never taking more than you give.
     9  #
    10  #***********************************************************************
    11  #
    12  # Ticket #3757:  The cost functions on the query optimizer for the
    13  # IN operator can be improved.
    14  #
    15  # $Id: tkt3757.test,v 1.1 2009/03/29 00:13:04 drh Exp $
    16  
    17  set testdir [file dirname $argv0]
    18  source $testdir/tester.tcl
    19  
    20  # Evaluate SQL.  Return the result set followed by the
    21  # and the number of full-scan steps.
    22  #
    23  proc count_steps {sql} {
    24    set r [db eval $sql]
    25    lappend r scan [db status step] sort [db status sort]
    26  }
    27  
    28  # Construct tables
    29  #
    30  do_test tkt3757-1.1 {
    31    db eval {
    32       CREATE TABLE t1(x INTEGER, y INTEGER, z TEXT);
    33       CREATE INDEX t1i1 ON t1(y,z);
    34       INSERT INTO t1 VALUES(1,2,'three');
    35       CREATE TABLE t2(a INTEGER, b TEXT);
    36       INSERT INTO t2 VALUES(2, 'two');
    37       ANALYZE;
    38       SELECT * FROM sqlite_stat1 ORDER BY 1, 2;
    39    }
    40  } {t1 t1i1 {1 1 1} t2 {} 1}
    41  
    42  # Modify statistics in order to make the optimizer then that:
    43  #
    44  #   (1)  Table T1 has about 250K entries
    45  #   (2)  There are only about 5 distinct values of T1.
    46  #
    47  # Then run a query with "t1.y IN (SELECT ..)" in the WHERE clause.
    48  # Make sure the index is used.
    49  #
    50  do_test tkt3757-1.2 {
    51    db eval {
    52      DELETE FROM sqlite_stat1;
    53      INSERT INTO sqlite_stat1 VALUES('t1','t1i1','250000 50000 30');
    54    }
    55    count_steps {
    56      SELECT * FROM t1 WHERE y IN (SELECT a FROM t2)
    57    }
    58  } {1 2 three scan 0 sort 0}
    59  
    60  finish_test