BUG#20141 "User-defined variables are not replicated properly for

          SF/Triggers in SBR mode."
BUG#14914 "SP: Uses of session variables in routines are not always replicated"
BUG#25167 "Dupl. usage of user-variables in trigger/function is not replicated
          correctly"

User-defined variables used inside of stored functions/triggers in
statements which did not update tables directly were not replicated.
We also had problems with replication of user-defined variables which
were used in triggers (or stored functions called from table-updating
statements) more than once.

This patch addresses the first issue by enabling logging of all
references to user-defined variables in triggers/stored functions
and not only references from table-updating statements.

The second issue stemmed from the fact that for user-defined
variables used from triggers or stored functions called from
table-updating statements we were writing binlog events for each
reference instead of only one event for the first reference.
This problem is already solved for stored functions called from
non-updating statements with help of "event unioning" mechanism.
So the patch simply extends this mechanism to the case affected.
It also fixes small problem in this mechanism which caused wrong
logging of references to user-variables in cases when non-updating
statement called several stored functions which used the same
variable and some of these function calls were omitted from binlog
as they were not updating any tables.

7 files changed, 508 insertions, 5 deletions

diff --git a/mysql-test/r/rpl_user_variables.result b/mysql-test/r/rpl_user_variables.result
index ed0d2782394..3b6002a5d2d 100644
--- a/mysql-test/r/rpl_user_variables.result
+++ b/mysql-test/r/rpl_user_variables.result
@@ -80,4 +80,178 @@ abc\def
 This is a test
 insert into t1 select * FROM (select @var1 union  select @var2) AS t2;
 drop table t1;
+End of 4.1 tests.
+DROP TABLE IF EXISTS t20;
+DROP TABLE IF EXISTS t21;
+DROP PROCEDURE IF EXISTS test.insert;
+CREATE TABLE t20 (a VARCHAR(20));
+CREATE TABLE t21 (a VARCHAR(20));
+CREATE PROCEDURE test.insert()
+BEGIN
+IF (@VAR)
+THEN
+INSERT INTO test.t20 VALUES ('SP_TRUE');
+ELSE
+INSERT INTO test.t20 VALUES ('SP_FALSE');
+END IF;
+END|
+CREATE TRIGGER test.insert_bi BEFORE INSERT
+ON test.t20 FOR EACH ROW
+BEGIN
+IF (@VAR)
+THEN
+INSERT INTO test.t21 VALUES ('TRIG_TRUE');
+ELSE
+INSERT INTO test.t21 VALUES ('TRIG_FALSE');
+END IF;
+END|
+SET @VAR=0;
+CALL test.insert();
+SET @VAR=1;
+CALL test.insert();
+On master: Check the tables for correct data
+SELECT * FROM t20;
+a
+SP_FALSE
+SP_TRUE
+SELECT * FROM t21;
+a
+TRIG_FALSE
+TRIG_TRUE
+On slave: Check the tables for correct data and it matches master
+SELECT * FROM t20;
+a
+SP_FALSE
+SP_TRUE
+SELECT * FROM t21;
+a
+TRIG_FALSE
+TRIG_TRUE
+DROP TABLE t20;
+DROP TABLE t21;
+DROP PROCEDURE test.insert;
+DROP TABLE IF EXISTS t1;
+DROP FUNCTION IF EXISTS test.square;
+CREATE TABLE t1 (i INT);
+CREATE FUNCTION test.square() RETURNS INTEGER DETERMINISTIC RETURN 
+(@var * @var);
+SET @var = 1;
+INSERT INTO t1 VALUES (square());
+SET @var = 2;
+INSERT INTO t1 VALUES (square());
+SET @var = 3;
+INSERT INTO t1 VALUES (square());
+SET @var = 4;
+INSERT INTO t1 VALUES (square());
+SET @var = 5;
+INSERT INTO t1 VALUES (square());
+On master: Retrieve the values from the table
+SELECT * FROM t1;
+i
+1
+4
+9
+16
+25
+On slave: Retrieve the values from the table and verify they are the same as on master
+SELECT * FROM t1;
+i
+1
+4
+9
+16
+25
+DROP TABLE t1;
+DROP FUNCTION test.square;
+DROP TABLE IF EXISTS t1;
+DROP FUNCTION IF EXISTS f1;
+DROP FUNCTION IF EXISTS f2;
+CREATE TABLE t1(a int);
+CREATE FUNCTION f1() returns int deterministic BEGIN
+return @a;
+END |
+CREATE FUNCTION f2() returns int deterministic BEGIN
+IF (@b > 0) then
+SET @c = (@a + @b);
+else
+SET @c = (@a - 1);
+END if;
+return @c;
+END |
+SET @a=500;
+INSERT INTO t1 values(f1());
+SET @b = 125;
+SET @c = 1;
+INSERT INTO t1 values(f2());
+On master: Retrieve the values from the table
+SELECT * from t1;
+a
+500
+625
+On slave: Check the tables for correct data and it matches master
+SELECT * from t1;
+a
+500
+625
+DROP TABLE t1;
+DROP FUNCTION f1;
+DROP FUNCTION f2;
+DROP TABLE IF EXISTS t1;
+DROP TABLE IF EXISTS t2;
+CREATE TABLE t1 (i int);
+CREATE TABLE t2 (k int);
+CREATE trigger t1_bi before INSERT on t1 for each row BEGIN
+INSERT INTO t2 values (@a);
+SET @a:=42;
+INSERT INTO t2 values (@a);
+END |
+SET @a:=100;
+INSERT INTO t1 values (5);
+On master: Check to see that data was inserted correctly in both tables
+SELECT * from t1;
+i
+5
+SELECT * from t2;
+k
+100
+42
+On slave: Check the tables for correct data and it matches master
+SELECT * from t1;
+i
+5
+SELECT * from t2;
+k
+100
+42
+End of 5.0 tests.
+DROP TABLE t1;
+DROP TABLE t2;
+DROP TABLE IF EXISTS t1;
+DROP FUNCTION IF EXISTS f1;
+DROP FUNCTION IF EXISTS f2;
+CREATE TABLE t1 (i INT);
+CREATE FUNCTION f1() RETURNS INT RETURN @a;
+CREATE 
+FUNCTION f2() RETURNS INT BEGIN
+INSERT INTO t1 VALUES (10 + @a);
+RETURN 0;
+END|
+SET @a:=123;
+SELECT f1(), f2();
+f1()	f2()
+123	0
+On master: Check to see that data was inserted correctly
+INSERT INTO t1 VALUES(f1());
+SELECT * FROM t1;
+i
+133
+123
+On slave: Check the table for correct data and it matches master
+SELECT * FROM t1;
+i
+133
+123
+DROP FUNCTION f1;
+DROP FUNCTION f2;
+DROP TABLE t1;
 stop slave;
diff --git a/mysql-test/t/rpl_user_variables.test b/mysql-test/t/rpl_user_variables.test
index 08717fce114..226591bd13f 100644
--- a/mysql-test/t/rpl_user_variables.test
+++ b/mysql-test/t/rpl_user_variables.test
@@ -53,5 +53,302 @@ SELECT * FROM t1 ORDER BY n;
 connection master;
 insert into t1 select * FROM (select @var1 union  select @var2) AS t2;
 drop table t1;
+--echo End of 4.1 tests.
+
+# BUG#20141
+# The following tests ensure that if user-defined variables are used in SF/Triggers 
+# that they are replicated correctly. These tests should be run in both SBR and RBR 
+# modes.
+
+# This test uses a procedure that inserts data values based on the value of a 
+# user-defined variable. It also has a trigger that inserts data based on the 
+# same variable. Successful test runs show that the @var is replicated 
+# properly and that the procedure and trigger insert the correct data on the 
+# slave.
+#
+# The test of stored procedure was included for completeness. Replication of stored 
+# procedures was not directly affected by BUG#20141.
+#
+# This test was constructed for BUG#20141
+
+--disable_warnings
+DROP TABLE IF EXISTS t20;
+DROP TABLE IF EXISTS t21;
+DROP PROCEDURE IF EXISTS test.insert;
+--enable_warnings
+
+CREATE TABLE t20 (a VARCHAR(20));
+CREATE TABLE t21 (a VARCHAR(20));
+DELIMITER |;
+
+# Create a procedure that uses the @var for flow control
+
+CREATE PROCEDURE test.insert()
+BEGIN
+  IF (@VAR)
+  THEN
+      INSERT INTO test.t20 VALUES ('SP_TRUE');
+  ELSE
+      INSERT INTO test.t20 VALUES ('SP_FALSE');
+  END IF;
+END|
+
+# Create a trigger that uses the @var for flow control
+
+CREATE TRIGGER test.insert_bi BEFORE INSERT
+    ON test.t20 FOR EACH ROW
+    BEGIN
+      IF (@VAR)
+      THEN
+        INSERT INTO test.t21 VALUES ('TRIG_TRUE');
+      ELSE
+        INSERT INTO test.t21 VALUES ('TRIG_FALSE');
+      END IF;
+    END|
+DELIMITER ;|
+
+sync_slave_with_master;
+connection master;
+
+# Set @var and call the procedure, repeat with different values
+
+SET @VAR=0;
+CALL test.insert();
+SET @VAR=1;
+CALL test.insert();
+
+--echo On master: Check the tables for correct data
+
+SELECT * FROM t20;
+SELECT * FROM t21;
+
+sync_slave_with_master;
+
+--echo On slave: Check the tables for correct data and it matches master
+
+SELECT * FROM t20;
+SELECT * FROM t21;
+connection master;
+
+# Cleanup
+
+DROP TABLE t20;
+DROP TABLE t21;
+DROP PROCEDURE test.insert;
+
+# This test uses a stored function that uses user-defined variables to return data 
+# This test was constructed for BUG#20141
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP FUNCTION IF EXISTS test.square;
+--enable_warnings
+
+CREATE TABLE t1 (i INT);
+
+# Create function that returns a value from @var. In this case, the square function
+
+CREATE FUNCTION test.square() RETURNS INTEGER DETERMINISTIC RETURN 
+(@var * @var);
+
+# Set the @var to different values and insert them into a table
+
+SET @var = 1;
+INSERT INTO t1 VALUES (square());
+SET @var = 2;
+INSERT INTO t1 VALUES (square());
+SET @var = 3;
+INSERT INTO t1 VALUES (square());
+SET @var = 4;
+INSERT INTO t1 VALUES (square());
+SET @var = 5;
+INSERT INTO t1 VALUES (square());
+
+--echo On master: Retrieve the values from the table
+
+SELECT * FROM t1;
+
+sync_slave_with_master;
+
+--echo On slave: Retrieve the values from the table and verify they are the same as on master
+
+SELECT * FROM t1;
+
+connection master;
+
+# Cleanup
+
+DROP TABLE t1;
+DROP FUNCTION test.square;
+
+# This test uses stored functions that uses user-defined variables to return data 
+# based on the use of @vars inside a function body.
+# This test was constructed for BUG#14914
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP FUNCTION IF EXISTS f1;
+DROP FUNCTION IF EXISTS f2;
+--enable_warnings
+
+CREATE TABLE t1(a int);
+DELIMITER |;
+
+# Create a function that simply returns the value of an @var.
+# Create a function that uses an @var for flow control, creates and uses another 
+# @var and sets its value to a value based on another @var.
+
+CREATE FUNCTION f1() returns int deterministic BEGIN
+  return @a;
+END |
+
+CREATE FUNCTION f2() returns int deterministic BEGIN
+  IF (@b > 0) then
+    SET @c = (@a + @b);
+  else
+    SET @c = (@a - 1);
+  END if;
+  return @c;
+END |
+DELIMITER ;|
+
+sync_slave_with_master;
+connection master;
+
+# Set an @var to a value and insert data into a table using the first function.
+# Set two more @vars to some values and insert data into a table using the second function.
+
+SET @a=500;
+INSERT INTO t1 values(f1());
+SET @b = 125;
+SET @c = 1;
+INSERT INTO t1 values(f2());
+
+--echo On master: Retrieve the values from the table
+
+sync_slave_with_master;
+connection master;
+
+SELECT * from t1;
+
+connection slave;
+
+--echo On slave: Check the tables for correct data and it matches master
+
+SELECT * from t1;
+
+connection master;
+
+# Cleanup
+
+DROP TABLE t1;
+DROP FUNCTION f1;
+DROP FUNCTION f2;
+
+# This test uses a function that changes a user-defined variable in its body. This test 
+# will ensure the @vars are replicated when needed and not interrupt the normal execution 
+# of the function on the slave. This also applies to procedures and triggers.
+
+# This test was constructed for BUG#25167
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP TABLE IF EXISTS t2;
+--enable_warnings
+CREATE TABLE t1 (i int);
+CREATE TABLE t2 (k int);
+DELIMITER |;
+
+# Create a trigger that inserts data into another table, changes the @var then inserts 
+# another row with the modified value.
+
+CREATE trigger t1_bi before INSERT on t1 for each row BEGIN
+  INSERT INTO t2 values (@a);
+  SET @a:=42;
+  INSERT INTO t2 values (@a);
+END |
+DELIMITER ;|
+
+sync_slave_with_master;
+connection master;
+
+# Set the @var to a value then insert data into first table.
+
+SET @a:=100;
+INSERT INTO t1 values (5);
+
+--echo On master: Check to see that data was inserted correctly in both tables
+
+SELECT * from t1;
+SELECT * from t2;
+
+sync_slave_with_master;
+
+--echo On slave: Check the tables for correct data and it matches master
+
+SELECT * from t1;
+SELECT * from t2;
+
+connection master;
+
+--echo End of 5.0 tests.
+
+# Cleanup
+
+DROP TABLE t1;
+DROP TABLE t2;
+
+# This test uses a stored function that uses user-defined variables to return data 
+# The test ensures the value of the user-defined variable is replicated correctly 
+# and in the correct order of assignment.
+
+# This test was constructed for BUG#20141
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP FUNCTION IF EXISTS f1;
+DROP FUNCTION IF EXISTS f2;
+--enable_warnings
+
+CREATE TABLE t1 (i INT);
+
+# Create two functions. One simply returns the user-defined variable. The other 
+# returns a value based on the user-defined variable.
+
+CREATE FUNCTION f1() RETURNS INT RETURN @a; DELIMITER |; CREATE 
+FUNCTION f2() RETURNS INT BEGIN
+  INSERT INTO t1 VALUES (10 + @a);
+  RETURN 0;
+END|
+DELIMITER ;|
+
+sync_slave_with_master;
+connection master;
+
+# Set the variable and execute the functions.
+
+SET @a:=123;
+SELECT f1(), f2();
+
+--echo On master: Check to see that data was inserted correctly
+
+INSERT INTO t1 VALUES(f1());
+SELECT * FROM t1;
+
+sync_slave_with_master;
+
+--echo On slave: Check the table for correct data and it matches master
+
+SELECT * FROM t1;
+
+connection master;
+
+# Cleanup
+
+DROP FUNCTION f1;
+DROP FUNCTION f2;
+DROP TABLE t1;
+
 sync_slave_with_master;
 stop slave;
+ 
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 1e89a579420..bde0c67257e 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -4220,7 +4220,14 @@ int get_var_with_binlog(THD *thd, enum_sql_command sql_command,
   user_var_entry *var_entry;
   var_entry= get_variable(&thd->user_vars, name, 0);
 
-  if (!(opt_bin_log && is_update_query(sql_command)))
+  /*
+    Any reference to user-defined variable which is done from stored
+    function or trigger affects their execution and execution of calling
+    statement. Hence we want to log all accesses to such variables and
+    not only those that happen from table-updating statement.
+  */
+  if (!(opt_bin_log && 
+       (is_update_query(sql_command) || thd->in_sub_stmt)))
   {
     *out_entry= var_entry;
     return 0;
diff --git a/sql/log.cc b/sql/log.cc
index 5ec1826b991..0615deed3ca 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -3350,13 +3350,13 @@ bool MYSQL_BIN_LOG::flush_and_sync()
   return err;
 }
 
-void MYSQL_BIN_LOG::start_union_events(THD *thd)
+void MYSQL_BIN_LOG::start_union_events(THD *thd, query_id_t query_id_param)
 {
   DBUG_ASSERT(!thd->binlog_evt_union.do_union);
   thd->binlog_evt_union.do_union= TRUE;
   thd->binlog_evt_union.unioned_events= FALSE;
   thd->binlog_evt_union.unioned_events_trans= FALSE;
-  thd->binlog_evt_union.first_query_id= thd->query_id;
+  thd->binlog_evt_union.first_query_id= query_id_param;
 }
 
 void MYSQL_BIN_LOG::stop_union_events(THD *thd)
diff --git a/sql/log.h b/sql/log.h
index 61db7052f75..b7891f94882 100644
--- a/sql/log.h
+++ b/sql/log.h
@@ -341,7 +341,7 @@ public:
 
   int  write_cache(IO_CACHE *cache, bool lock_log, bool flush_and_sync);
 
-  void start_union_events(THD *thd);
+  void start_union_events(THD *thd, query_id_t query_id_param);
   void stop_union_events(THD *thd);
   bool is_query_in_union(THD *thd, query_id_t query_id_param);
 
diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index 7c110185a95..7405ea37314 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -1485,8 +1485,24 @@ sp_head::execute_function(THD *thd, Item **argp, uint argcount,
 
   if (need_binlog_call)
   {
+    query_id_t q;
     reset_dynamic(&thd->user_var_events);
-    mysql_bin_log.start_union_events(thd);
+    /*
+      In case of artificially constructed events for function calls
+      we have separate union for each such event and hence can't use
+      query_id of real calling statement as the start of all these
+      unions (this will break logic of replication of user-defined
+      variables). So we use artifical value which is guaranteed to
+      be greater than all query_id's of all statements belonging
+      to previous events/unions.
+      Possible alternative to this is logging of all function invocations
+      as one select and not resetting THD::user_var_events before
+      each invocation.
+    */
+    VOID(pthread_mutex_lock(&LOCK_thread_count));
+    q= ::query_id;
+    VOID(pthread_mutex_unlock(&LOCK_thread_count));
+    mysql_bin_log.start_union_events(thd, q + 1);
     binlog_save_options= thd->options;
     thd->options&= ~OPTION_BIN_LOG;
   }
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index 7309e79a666..a0ad3607ead 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -2158,6 +2158,11 @@ void THD::reset_sub_statement_state(Sub_statement_state *backup,
   {
     options&= ~OPTION_BIN_LOG;
   }    
+
+  if ((backup->options & OPTION_BIN_LOG) && is_update_query(lex->sql_command)&&
+      !current_stmt_binlog_row_based)
+    mysql_bin_log.start_union_events(this, this->query_id);
+
   /* Disable result sets */
   client_capabilities &= ~CLIENT_MULTI_RESULTS;
   in_sub_stmt|= new_state;
@@ -2201,6 +2206,10 @@ void THD::restore_sub_statement_state(Sub_statement_state *backup)
   sent_row_count=   backup->sent_row_count;
   client_capabilities= backup->client_capabilities;
 
+  if ((options & OPTION_BIN_LOG) && is_update_query(lex->sql_command) &&
+    !current_stmt_binlog_row_based)
+    mysql_bin_log.stop_union_events(this);
+ 
   /*
     The following is added to the old values as we are interested in the
     total complexity of the query