Bug #25543 Replication of wrong values if using rand() in stored procedure

When rand() is called multiple times inside a stored procedure, the server does 
not binlog the correct random seed values.

This patch corrects the problem by resetting rand_used= 0 in 
THD::cleanup_after_query() allowing the system to save the random seeds if needed
for each command in a stored procedure body.

However, rand_used is not reset if executing in a stored function or trigger 
because these operations are binlogged by call and thus only the calling statement
need detect the call to rand() made by its substatements. These substatements must 
not set rand_used to 0 because it would remove the detection of rand() by the 
calling statement.


mysql-test/r/rpl_misc_functions.result:
  Bug #25543 Replication of wrong values if using rand() in stored procedure
  
  The result file was modified to include the correct processing of the new
  additions to the test. The results from execution are written to files on 
  both the master and the slave. The files are compared to ensure the values 
  from rand() generated on the master are correctly generated on the slave.
mysql-test/t/rpl_misc_functions.test:
  Bug #25543 Replication of wrong values if using rand() in stored procedure
  
  The test was modified to include a test of a stored procedure that calls
  the rand() function multiple times. 
  
  The results from execution are written to files on both the master and the
  slave. The files are compared to ensure the values from rand() generated
  on the master are correctly generated on the slave.
sql/sql_class.cc:
  Bug #25543 Replication of wrong values if using rand() in stored procedure
  
  The code was modified to reset rand_used so that detection of calls to rand() 
  will save random seeds if needed by the slave.

1 files changed, 12 insertions, 0 deletions

diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 3c91e3e8fb7..adb7323c463 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -575,6 +575,18 @@ void THD::cleanup_after_query()
     clear_next_insert_id= 0;
     next_insert_id= 0;
   }
+  /*
+    Reset rand_used so that detection of calls to rand() will save random 
+    seeds if needed by the slave.
+
+    Do not reset rand_used if inside a stored function or trigger because 
+    only the call to these operations is logged. Thus only the calling 
+    statement needs to detect rand() calls made by its substatements. These
+    substatements must not set rand_used to 0 because it would remove the
+    detection of rand() by the calling statement. 
+  */
+  if (!in_sub_stmt)
+    rand_used= 0;
   /* Free Items that were created during this execution */
   free_items();
   /* Reset where. */