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      1 # 2007 May 12
      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 # This file tests a special case in the b-tree code that can be
     12 # hit by the "IN" operator (or EXISTS, NOT IN, etc.).
     13 #
     14 # $Id: in2.test,v 1.3 2008/07/12 14:52:20 drh Exp $
     15 
     16 set testdir [file dirname $argv0]
     17 source $testdir/tester.tcl
     18 
     19 do_test in2-1 {
     20   execsql {
     21     CREATE TABLE a(i INTEGER PRIMARY KEY, a);
     22   }
     23 } {}
     24 
     25 set ::N 2000
     26 
     27 do_test in2-2 {
     28   db transaction {
     29     for {set ::ii 0} {$::ii < $::N} {incr ::ii} {
     30       execsql {INSERT INTO a VALUES($::ii, $::ii)}
     31     }
     32     execsql {INSERT INTO a VALUES(4000, '')}
     33 
     34     for {set ::ii 0} {$::ii < $::N} {incr ::ii} {
     35       set ::t [format "x%04d" $ii]
     36       execsql {INSERT INTO a VALUES(NULL, $::t)}
     37     }
     38   }
     39 } {}
     40 
     41 # Each iteration of this loop builds a slightly different b-tree to
     42 # evaluate the "IN (...)" operator in the SQL statement. The contents
     43 # of the b-tree are (in sorted order):
     44 #
     45 #     $::ii integers.
     46 #     a string of zero length.
     47 #     $::N short strings.
     48 #
     49 # Records are inserted in sorted order.
     50 #
     51 # The string of zero-length is stored in a b-tree cell with 3 bytes
     52 # of payload. Moving this cell from a leaf node to a internal node 
     53 # during b-tree balancing was causing an assertion failure. 
     54 #
     55 # This bug only applied to b-trees generated to evaluate IN (..) 
     56 # clauses, as it is impossible for persistent b-trees (SQL tables + 
     57 # indices) to contain cells smaller than 4 bytes.
     58 #
     59 for {set ::ii 3} {$::ii < $::N} {incr ::ii} {
     60   do_test in2-$::ii {
     61     execsql {
     62       SELECT 1 IN (SELECT a FROM a WHERE (i < $::ii) OR (i >= $::N))
     63     }
     64   } {1}
     65 }
     66 
     67 finish_test
     68