bzr commit into mysql-6.0-rpl branch (luis.soares:2805) Bug#42444

[Luis Soares]

#At file:///home/lsoares/Workspace/mysql-server/bugfix/42444/6.0-rpl/

 2805 Luis Soares	2009-01-29
      BUG#42444: main.change_user: result from com_select differs between embedded and other runs
            
      In 6.0-rpl this test was failing when mtr was running tests in embedded mode.
            
      This happened because when in embedded mode, mtr does run "check_testcase" which
      seems to cause extra selects. Since this test case relies on:
      
      SHOW GLOBAL STATUS LIKE 'com_select';
      
      for passing, this will get different values whether mtr is run in embedded 
      mode or other modes, therefore the test failure surfaces.
            
      This patch address this issue by making the part of the test dependent from 
      SHOW GLOBAL STATUS LIKE 'com_select'; to work with relative instead of 
      absolute values (have a test start timestamp and then subtract it in 
      the checks).
modified:
  mysql-test/r/change_user.result
  mysql-test/t/change_user.test

=== modified file 'mysql-test/r/change_user.result'
--- a/mysql-test/r/change_user.result	2009-01-26 16:03:39 +0000
+++ b/mysql-test/r/change_user.result	2009-01-29 11:05:07 +0000
@@ -51,9 +51,3 @@ SELECT IS_USED_LOCK('bug31418');
 IS_USED_LOCK('bug31418')
 NULL
 FLUSH STATUS;
-SHOW GLOBAL STATUS LIKE 'com_select';
-Variable_name	Value
-Com_select	119
-SHOW GLOBAL STATUS LIKE 'com_select';
-Variable_name	Value
-Com_select	119

=== modified file 'mysql-test/t/change_user.test'
--- a/mysql-test/t/change_user.test	2009-01-26 16:03:39 +0000
+++ b/mysql-test/t/change_user.test	2009-01-29 11:05:07 +0000
@@ -53,6 +53,7 @@ SELECT IS_USED_LOCK('bug31418');
 
 FLUSH STATUS;
 
+let $start= query_get_value(SHOW GLOBAL STATUS LIKE 'com_select', Value, 1);
 --disable_result_log
 --disable_query_log
 
@@ -68,8 +69,20 @@ while ($i)
 --enable_query_log
 --enable_result_log
 
-SHOW GLOBAL STATUS LIKE 'com_select';
+let $probe= query_get_value(SHOW GLOBAL STATUS LIKE 'com_select', Value, 1);
+let $before= `SELECT $probe - $start`;
 
 --change_user
 
-SHOW GLOBAL STATUS LIKE 'com_select';
+let $probe= query_get_value(SHOW GLOBAL STATUS LIKE 'com_select', Value, 1);
+let $after= `SELECT $probe - $start`;
+
+# we check to see if the value is the same after the change user. note that we 
+# need to add one to the $before variable as we need to account for the 
+# select in the "let $before=`SELECT $probe - $start`" instruction
+if (!`SELECT $after = $before+1`)
+{
+  let $expected= `SELECT $before+1`;
+  --echo Expected: $expected, Got: $after
+  die select count mismatch!;
+}