WL#3259 (RBR with more columns on slave than master):

Incorporating changes from review.
Fixing one bug that surfaced.


mysql-test/extra/rpl_tests/rpl_row_tabledefs.test:
  Adding tests that UPDATE and DELETE does not generate an error.
mysql-test/r/rpl_row_tabledefs_2myisam.result:
  Result change.
mysql-test/r/rpl_row_tabledefs_3innodb.result:
  Result change.
mysql-test/t/disabled.def:
  Enabling rpl_sp_effects (even though it gives a result mismatch currently).
sql/field.cc:
  Using constant to denote undefined last null byte.
sql/field.h:
  Using constant to denote undefined last null byte.
  Adding documentation.
sql/log_event.cc:
  Not generating error for non-NULL no-DEFAULT columns when updating or deleting row.
  Better documentation and comments.
sql/rpl_utility.cc:
  Moving documentation to header file.
sql/rpl_utility.h:
  Documenting class and members.

9 files changed, 441 insertions, 62 deletions

diff --git a/mysql-test/extra/rpl_tests/rpl_row_tabledefs.test b/mysql-test/extra/rpl_tests/rpl_row_tabledefs.test
index b17103d8396..1d39a2c3efd 100644
--- a/mysql-test/extra/rpl_tests/rpl_row_tabledefs.test
+++ b/mysql-test/extra/rpl_tests/rpl_row_tabledefs.test
@@ -25,6 +25,8 @@ eval CREATE TABLE t3 (a INT PRIMARY KEY, b INT) ENGINE=$engine_type;
 eval CREATE TABLE t4 (a INT) ENGINE=$engine_type;
 eval CREATE TABLE t5 (a INT, b INT, c INT) ENGINE=$engine_type;
 eval CREATE TABLE t6 (a INT, b INT, c INT) ENGINE=$engine_type;
+eval CREATE TABLE t7 (a INT NOT NULL) ENGINE=$engine_type;
+eval CREATE TABLE t8 (a INT NOT NULL) ENGINE=$engine_type;
 
 # Table used to detect that slave is running
 eval CREATE TABLE t9 (a INT) ENGINE=$engine_type;
@@ -53,6 +55,17 @@ ALTER TABLE t5 MODIFY b FLOAT;
 # ... change the type of the last column of table 't6'
 ALTER TABLE t6 MODIFY c FLOAT;
 
+# ... add one byte worth of null bytes to the table on the slave
+ALTER TABLE t7 ADD e1 INT, ADD e2 INT, ADD e3 INT, ADD e4 INT,
+               ADD e5 INT, ADD e6 INT, ADD e7 INT, ADD e8 INT;
+
+# ... add 8 columns that are nullable: t8 will not be entirely
+#     nullable and have no null bits (just an X bit)
+ALTER TABLE t8 ADD e1 INT NOT NULL DEFAULT 0, ADD e2 INT NOT NULL DEFAULT 0,
+               ADD e3 INT NOT NULL DEFAULT 0, ADD e4 INT NOT NULL DEFAULT 0,
+               ADD e5 INT NOT NULL DEFAULT 0, ADD e6 INT NOT NULL DEFAULT 0,
+               ADD e7 INT NOT NULL DEFAULT 0, ADD e8 INT NOT NULL DEFAULT 0;
+        
 # Insert some values for tables on slave side. These should not be
 # modified when the row from the master is applied.
 INSERT INTO t1_int  VALUES (2, 4, 4711);
@@ -90,7 +103,7 @@ SELECT a,b,x FROM t1_int;
 SELECT a,b,HEX(x),HEX(y),HEX(z) FROM t1_bit;
 SELECT a,b,x FROM t1_char;
 
-# Each of these should generate an error and stop the slave
+# Each of these inserts should generate an error and stop the slave
 
 connection master;
 INSERT INTO t9 VALUES (2);
@@ -163,8 +176,59 @@ SET GLOBAL SQL_SLAVE_SKIP_COUNTER=2;
 START SLAVE;
 
 connection master;
+INSERT INTO t9 VALUES (6);
+sync_slave_with_master;
+--replace_result $MASTER_MYPORT MASTER_PORT
+--replace_column 1 # 7 # 8 # 9 # 22 # 23 # 33 #
+--query_vertical SHOW SLAVE STATUS
+
+# Testing some tables extra field that can be null and cannot be null
+# (but have default values)
+
+connection master;
+INSERT INTO t7 VALUES (1),(2),(3);
+INSERT INTO t8 VALUES (1),(2),(3);
+SELECT * FROM t7;
+SELECT * FROM t8;
+sync_slave_with_master;
+SELECT * FROM t7;
+SELECT * FROM t8;
+
+# We will now try to update and then delete a row on the master where
+# the extra field on the slave does not have a default value. This
+# update should not generate an error even though there is no default
+# for the extra column. 
+
+--echo **** On Master ****
+connection master;
+TRUNCATE t1_nodef;
+SET SQL_LOG_BIN=0;
+INSERT INTO t1_nodef VALUES (1,2);
+INSERT INTO t1_nodef VALUES (2,4);
+SET SQL_LOG_BIN=1;
+--echo **** On Slave ****
+connection slave;
+INSERT INTO t1_nodef VALUES (1,2,3);
+INSERT INTO t1_nodef VALUES (2,4,6);
+--echo **** On Master ****
+connection master;
+UPDATE t1_nodef SET b=2*b WHERE a=1;
+SELECT * FROM t1_nodef;
+--echo **** On Slave ****
+sync_slave_with_master;
+SELECT * FROM t1_nodef;
+--echo **** On Master ****
+connection master;
+DELETE FROM t1_nodef WHERE a=2;
+SELECT * FROM t1_nodef;
+--echo **** On Slave ****
+sync_slave_with_master;
+SELECT * FROM t1_nodef;
+
+--echo **** Cleanup ****
+connection master;
 --disable_warnings
 DROP TABLE IF EXISTS t1_int,t1_bit,t1_char,t1_nodef;
-DROP TABLE IF EXISTS t2,t3,t4,t5,t6,t9;
+DROP TABLE IF EXISTS t2,t3,t4,t5,t6,t7,t8,t9;
 --enable_warnings
 sync_slave_with_master;
diff --git a/mysql-test/r/rpl_row_tabledefs_2myisam.result b/mysql-test/r/rpl_row_tabledefs_2myisam.result
index 37559b0412a..ae792a5dc2a 100644
--- a/mysql-test/r/rpl_row_tabledefs_2myisam.result
+++ b/mysql-test/r/rpl_row_tabledefs_2myisam.result
@@ -16,6 +16,8 @@ CREATE TABLE t3 (a INT PRIMARY KEY, b INT) ENGINE='MyISAM';
 CREATE TABLE t4 (a INT) ENGINE='MyISAM';
 CREATE TABLE t5 (a INT, b INT, c INT) ENGINE='MyISAM';
 CREATE TABLE t6 (a INT, b INT, c INT) ENGINE='MyISAM';
+CREATE TABLE t7 (a INT NOT NULL) ENGINE='MyISAM';
+CREATE TABLE t8 (a INT NOT NULL) ENGINE='MyISAM';
 CREATE TABLE t9 (a INT) ENGINE='MyISAM';
 ALTER TABLE t1_int ADD x INT DEFAULT 42;
 ALTER TABLE t1_bit
@@ -28,6 +30,12 @@ ALTER TABLE t2 DROP b;
 ALTER TABLE t4 MODIFY a FLOAT;
 ALTER TABLE t5 MODIFY b FLOAT;
 ALTER TABLE t6 MODIFY c FLOAT;
+ALTER TABLE t7 ADD e1 INT, ADD e2 INT, ADD e3 INT, ADD e4 INT,
+ADD e5 INT, ADD e6 INT, ADD e7 INT, ADD e8 INT;
+ALTER TABLE t8 ADD e1 INT NOT NULL DEFAULT 0, ADD e2 INT NOT NULL DEFAULT 0,
+ADD e3 INT NOT NULL DEFAULT 0, ADD e4 INT NOT NULL DEFAULT 0,
+ADD e5 INT NOT NULL DEFAULT 0, ADD e6 INT NOT NULL DEFAULT 0,
+ADD e7 INT NOT NULL DEFAULT 0, ADD e8 INT NOT NULL DEFAULT 0;
 INSERT INTO t1_int  VALUES (2, 4, 4711);
 INSERT INTO t1_char VALUES (2, 4, 'Foo is a bar');
 INSERT INTO t1_bit  VALUES (2, 4, b'101', b'11100', b'01');
@@ -151,7 +159,7 @@ Replicate_Do_Table
 Replicate_Ignore_Table	
 Replicate_Wild_Do_Table	
 Replicate_Wild_Ignore_Table	
-Last_Errno	1514
+Last_Errno	1522
 Last_Error	Table width mismatch - received 2 columns, test.t2 has 1 columns
 Skip_Counter	0
 Exec_Master_Log_Pos	#
@@ -189,7 +197,7 @@ Replicate_Do_Table
 Replicate_Ignore_Table	
 Replicate_Wild_Do_Table	
 Replicate_Wild_Ignore_Table	
-Last_Errno	1514
+Last_Errno	1522
 Last_Error	Column 0 type mismatch - received type 3, test.t4 has type 4
 Skip_Counter	0
 Exec_Master_Log_Pos	#
@@ -227,7 +235,7 @@ Replicate_Do_Table
 Replicate_Ignore_Table	
 Replicate_Wild_Do_Table	
 Replicate_Wild_Ignore_Table	
-Last_Errno	1514
+Last_Errno	1522
 Last_Error	Column 1 type mismatch - received type 3, test.t5 has type 4
 Skip_Counter	0
 Exec_Master_Log_Pos	#
@@ -265,7 +273,7 @@ Replicate_Do_Table
 Replicate_Ignore_Table	
 Replicate_Wild_Do_Table	
 Replicate_Wild_Ignore_Table	
-Last_Errno	1514
+Last_Errno	1522
 Last_Error	Column 2 type mismatch - received type 3, test.t6 has type 4
 Skip_Counter	0
 Exec_Master_Log_Pos	#
@@ -282,5 +290,92 @@ Master_SSL_Key
 Seconds_Behind_Master	#
 SET GLOBAL SQL_SLAVE_SKIP_COUNTER=2;
 START SLAVE;
+INSERT INTO t9 VALUES (6);
+SHOW SLAVE STATUS;
+Slave_IO_State	#
+Master_Host	127.0.0.1
+Master_User	root
+Master_Port	MASTER_PORT
+Connect_Retry	1
+Master_Log_File	master-bin.000001
+Read_Master_Log_Pos	#
+Relay_Log_File	#
+Relay_Log_Pos	#
+Relay_Master_Log_File	master-bin.000001
+Slave_IO_Running	Yes
+Slave_SQL_Running	Yes
+Replicate_Do_DB	
+Replicate_Ignore_DB	
+Replicate_Do_Table	
+Replicate_Ignore_Table	
+Replicate_Wild_Do_Table	
+Replicate_Wild_Ignore_Table	
+Last_Errno	0
+Last_Error	
+Skip_Counter	0
+Exec_Master_Log_Pos	#
+Relay_Log_Space	#
+Until_Condition	None
+Until_Log_File	
+Until_Log_Pos	0
+Master_SSL_Allowed	No
+Master_SSL_CA_File	
+Master_SSL_CA_Path	
+Master_SSL_Cert	
+Master_SSL_Cipher	
+Master_SSL_Key	
+Seconds_Behind_Master	#
+INSERT INTO t7 VALUES (1),(2),(3);
+INSERT INTO t8 VALUES (1),(2),(3);
+SELECT * FROM t7;
+a
+1
+2
+3
+SELECT * FROM t8;
+a
+1
+2
+3
+SELECT * FROM t7;
+a	e1	e2	e3	e4	e5	e6	e7	e8
+1	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+2	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+SELECT * FROM t8;
+a	e1	e2	e3	e4	e5	e6	e7	e8
+1	0	0	0	0	0	0	0	0
+2	0	0	0	0	0	0	0	0
+3	0	0	0	0	0	0	0	0
+**** On Master ****
+TRUNCATE t1_nodef;
+SET SQL_LOG_BIN=0;
+INSERT INTO t1_nodef VALUES (1,2);
+INSERT INTO t1_nodef VALUES (2,4);
+SET SQL_LOG_BIN=1;
+**** On Slave ****
+INSERT INTO t1_nodef VALUES (1,2,3);
+INSERT INTO t1_nodef VALUES (2,4,6);
+**** On Master ****
+UPDATE t1_nodef SET b=2*b WHERE a=1;
+SELECT * FROM t1_nodef;
+a	b
+1	4
+2	4
+**** On Slave ****
+SELECT * FROM t1_nodef;
+a	b	x
+1	4	3
+2	4	6
+**** On Master ****
+DELETE FROM t1_nodef WHERE a=2;
+SELECT * FROM t1_nodef;
+a	b
+1	4
+**** On Slave ****
+SELECT * FROM t1_nodef;
+a	b	x
+1	4	3
+**** Cleanup ****
 DROP TABLE IF EXISTS t1_int,t1_bit,t1_char,t1_nodef;
-DROP TABLE IF EXISTS t2,t3,t4,t5,t6,t9;
+DROP TABLE IF EXISTS t2,t3,t4,t5,t6,t7,t8,t9;
diff --git a/mysql-test/r/rpl_row_tabledefs_3innodb.result b/mysql-test/r/rpl_row_tabledefs_3innodb.result
index 0c1b25ec7fc..b7f0b7b15e2 100644
--- a/mysql-test/r/rpl_row_tabledefs_3innodb.result
+++ b/mysql-test/r/rpl_row_tabledefs_3innodb.result
@@ -16,6 +16,8 @@ CREATE TABLE t3 (a INT PRIMARY KEY, b INT) ENGINE='InnoDB';
 CREATE TABLE t4 (a INT) ENGINE='InnoDB';
 CREATE TABLE t5 (a INT, b INT, c INT) ENGINE='InnoDB';
 CREATE TABLE t6 (a INT, b INT, c INT) ENGINE='InnoDB';
+CREATE TABLE t7 (a INT NOT NULL) ENGINE='InnoDB';
+CREATE TABLE t8 (a INT NOT NULL) ENGINE='InnoDB';
 CREATE TABLE t9 (a INT) ENGINE='InnoDB';
 ALTER TABLE t1_int ADD x INT DEFAULT 42;
 ALTER TABLE t1_bit
@@ -28,6 +30,12 @@ ALTER TABLE t2 DROP b;
 ALTER TABLE t4 MODIFY a FLOAT;
 ALTER TABLE t5 MODIFY b FLOAT;
 ALTER TABLE t6 MODIFY c FLOAT;
+ALTER TABLE t7 ADD e1 INT, ADD e2 INT, ADD e3 INT, ADD e4 INT,
+ADD e5 INT, ADD e6 INT, ADD e7 INT, ADD e8 INT;
+ALTER TABLE t8 ADD e1 INT NOT NULL DEFAULT 0, ADD e2 INT NOT NULL DEFAULT 0,
+ADD e3 INT NOT NULL DEFAULT 0, ADD e4 INT NOT NULL DEFAULT 0,
+ADD e5 INT NOT NULL DEFAULT 0, ADD e6 INT NOT NULL DEFAULT 0,
+ADD e7 INT NOT NULL DEFAULT 0, ADD e8 INT NOT NULL DEFAULT 0;
 INSERT INTO t1_int  VALUES (2, 4, 4711);
 INSERT INTO t1_char VALUES (2, 4, 'Foo is a bar');
 INSERT INTO t1_bit  VALUES (2, 4, b'101', b'11100', b'01');
@@ -282,5 +290,92 @@ Master_SSL_Key
 Seconds_Behind_Master	#
 SET GLOBAL SQL_SLAVE_SKIP_COUNTER=2;
 START SLAVE;
+INSERT INTO t9 VALUES (6);
+SHOW SLAVE STATUS;
+Slave_IO_State	#
+Master_Host	127.0.0.1
+Master_User	root
+Master_Port	MASTER_PORT
+Connect_Retry	1
+Master_Log_File	master-bin.000001
+Read_Master_Log_Pos	#
+Relay_Log_File	#
+Relay_Log_Pos	#
+Relay_Master_Log_File	master-bin.000001
+Slave_IO_Running	Yes
+Slave_SQL_Running	Yes
+Replicate_Do_DB	
+Replicate_Ignore_DB	
+Replicate_Do_Table	
+Replicate_Ignore_Table	
+Replicate_Wild_Do_Table	
+Replicate_Wild_Ignore_Table	
+Last_Errno	0
+Last_Error	
+Skip_Counter	0
+Exec_Master_Log_Pos	#
+Relay_Log_Space	#
+Until_Condition	None
+Until_Log_File	
+Until_Log_Pos	0
+Master_SSL_Allowed	No
+Master_SSL_CA_File	
+Master_SSL_CA_Path	
+Master_SSL_Cert	
+Master_SSL_Cipher	
+Master_SSL_Key	
+Seconds_Behind_Master	#
+INSERT INTO t7 VALUES (1),(2),(3);
+INSERT INTO t8 VALUES (1),(2),(3);
+SELECT * FROM t7;
+a
+1
+2
+3
+SELECT * FROM t8;
+a
+1
+2
+3
+SELECT * FROM t7;
+a	e1	e2	e3	e4	e5	e6	e7	e8
+1	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+2	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+3	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
+SELECT * FROM t8;
+a	e1	e2	e3	e4	e5	e6	e7	e8
+1	0	0	0	0	0	0	0	0
+2	0	0	0	0	0	0	0	0
+3	0	0	0	0	0	0	0	0
+**** On Master ****
+TRUNCATE t1_nodef;
+SET SQL_LOG_BIN=0;
+INSERT INTO t1_nodef VALUES (1,2);
+INSERT INTO t1_nodef VALUES (2,4);
+SET SQL_LOG_BIN=1;
+**** On Slave ****
+INSERT INTO t1_nodef VALUES (1,2,3);
+INSERT INTO t1_nodef VALUES (2,4,6);
+**** On Master ****
+UPDATE t1_nodef SET b=2*b WHERE a=1;
+SELECT * FROM t1_nodef;
+a	b
+1	4
+2	4
+**** On Slave ****
+SELECT * FROM t1_nodef;
+a	b	x
+1	4	3
+2	4	6
+**** On Master ****
+DELETE FROM t1_nodef WHERE a=2;
+SELECT * FROM t1_nodef;
+a	b
+1	4
+**** On Slave ****
+SELECT * FROM t1_nodef;
+a	b	x
+1	4	3
+**** Cleanup ****
 DROP TABLE IF EXISTS t1_int,t1_bit,t1_char,t1_nodef;
-DROP TABLE IF EXISTS t2,t3,t4,t5,t6,t9;
+DROP TABLE IF EXISTS t2,t3,t4,t5,t6,t7,t8,t9;
diff --git a/mysql-test/t/disabled.def b/mysql-test/t/disabled.def
index f1322fcb699..a3bedbaa22d 100644
--- a/mysql-test/t/disabled.def
+++ b/mysql-test/t/disabled.def
@@ -36,7 +36,6 @@ rpl_row_blob_innodb      : BUG#18980 2006-04-10 kent    Test fails randomly
 rpl_row_func003		 : BUG#19074 2006-13-04 andrei  test failed
 rpl_row_inexist_tbl      : BUG#18948 2006-03-09 mats    Disabled since patch makes this test wait forever
 rpl_sp                   : BUG#16456 2006-02-16 jmiller
-rpl_sp_effects           : BUG#19862 2006-08-22 mats    Bug appear to be fixed
 rpl_until                : BUG#15886 2006-02-16 jmiller Unstable test case
 sp-goto                  : BUG#18949 2006-02-16 jmiller GOTO is currently is disabled - will be fixed in the future
 mysqldump                : BUG#18078 2006-03-10 lars
diff --git a/sql/field.cc b/sql/field.cc
index 340f33f1e01..479a562aaac 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -1261,7 +1261,10 @@ my_size_t
 Field::do_last_null_byte() const
 {
   DBUG_ASSERT(null_ptr == NULL || (byte*) null_ptr >= table->record[0]);
-  return null_ptr ? (byte*) null_ptr - table->record[0] + 1 : 0;
+  if (null_ptr)
+    return (byte*) null_ptr - table->record[0] + 1;
+  else
+    return LAST_NULL_BYTE_UNDEF;
 }
 
 
@@ -8196,7 +8199,10 @@ Field_bit::do_last_null_byte() const
   else
     result= bit_ptr;
 
-  return result ? (byte*) result - table->record[0] + 1 : 0;
+  if (result)
+    return (byte*) result - table->record[0] + 1;
+  else
+    return LAST_NULL_BYTE_UNDEF;
 }
 
 Field *Field_bit::new_key_field(MEM_ROOT *root,
diff --git a/sql/field.h b/sql/field.h
index 51b624b799f..26a9cd0b465 100644
--- a/sql/field.h
+++ b/sql/field.h
@@ -208,10 +208,24 @@ public:
   inline bool maybe_null(void) { return null_ptr != 0 || table->maybe_null; }
   inline bool real_maybe_null(void) { return null_ptr != 0; }
 
+  enum {
+    LAST_NULL_BYTE_UNDEF= 0
+  };
+
   /*
-    Return a pointer to the last byte of the null bytes where the
-    field conceptually is placed.  In the case that the field does not
-    use any bits of the null bytes, a null pointer is returned.
+    Find the position of the last null byte for the field.
+
+    SYNOPSIS
+      last_null_byte()
+
+    DESCRIPTION
+      Return a pointer to the last byte of the null bytes where the
+      field conceptually is placed.
+
+    RETURN VALUE
+      The position of the last null byte relative to the beginning of
+      the record. If the field does not use any bits of the null
+      bytes, the value 0 (LAST_NULL_BYTE_UNDEF) is returned.
    */
   my_size_t last_null_byte() const {
     my_size_t bytes= do_last_null_byte();
@@ -384,6 +398,17 @@ public:
   friend class Item_func_group_concat;
 
 private:
+  /*
+    Primitive for implementing last_null_byte().
+
+    SYNOPSIS
+      do_last_null_byte()
+
+    DESCRIPTION
+      Primitive for the implementation of the last_null_byte()
+      function. This represents the inheritance interface and can be
+      overridden by subclasses.
+   */
   virtual my_size_t do_last_null_byte() const;
 };
 
diff --git a/sql/log_event.cc b/sql/log_event.cc
index ceacc1eade7..ebfaa4bfff3 100644
--- a/sql/log_event.cc
+++ b/sql/log_event.cc
@@ -5304,7 +5304,7 @@ int Rows_log_event::do_add_row_data(byte *const row_data,
     row_end Pointer to variable that will hold the value of the
             one-after-end position for the row
     master_reclength
-            Pointer to variable that will hold the length of the
+            Pointer to variable that will be set to the length of the
             record on the master side
     rw_set  Pointer to bitmap that holds either the read_set or the
             write_set of the table
@@ -5317,13 +5317,22 @@ int Rows_log_event::do_add_row_data(byte *const row_data,
 
       At most 'colcnt' columns are read: if the table is larger than
       that, the remaining fields are not filled in.
+
+  RETURN VALUE
+
+      Error code, or zero if no error. The following error codes can
+      be returned:
+
+      ER_NO_DEFAULT_FOR_FIELD
+        Returned if one of the fields existing on the slave but not on
+        the master does not have a default value (and isn't nullable)
  */
 static int
 unpack_row(RELAY_LOG_INFO *rli,
            TABLE *table, uint const colcnt, byte *record,
            char const *row, MY_BITMAP const *cols,
            char const **row_end, ulong *master_reclength,
-           MY_BITMAP* const rw_set)
+           MY_BITMAP* const rw_set, Log_event_type const event_type)
 {
   DBUG_ASSERT(record && row);
   my_ptrdiff_t const offset= record - (byte*) table->record[0];
@@ -5334,10 +5343,20 @@ unpack_row(RELAY_LOG_INFO *rli,
     Field **fptr= &table->field[colcnt-1];
     do
       master_null_bytes= (*fptr)->last_null_byte();
-    while (master_null_bytes == 0 && fptr-- > table->field);
+    while (master_null_bytes == Field::LAST_NULL_BYTE_UNDEF &&
+           fptr-- > table->field);
+
+    /*
+      If master_null_bytes is LAST_NULL_BYTE_UNDEF (0) at this time,
+      there were no nullable fields nor BIT fields at all in the
+      columns that are common to the master and the slave. In that
+      case, there is only one null byte holding the X bit.
 
-    if (master_null_bytes == 0)
-      master_null_bytes= table->s->null_bytes;
+      OBSERVE! There might still be nullable columns following the
+      common columns, so table->s->null_bytes might be greater than 1.
+     */
+    if (master_null_bytes == Field::LAST_NULL_BYTE_UNDEF)
+      master_null_bytes= 1;
   }
 
   DBUG_ASSERT(master_null_bytes <= table->s->null_bytes);
@@ -5348,31 +5367,29 @@ unpack_row(RELAY_LOG_INFO *rli,
 
   Field **const begin_ptr = table->field;
   Field **field_ptr;
+  char const *ptr= row + master_null_bytes;
+  Field **const end_ptr= begin_ptr + colcnt;
+  for (field_ptr= begin_ptr ; field_ptr < end_ptr ; ++field_ptr)
   {
-    char const *ptr= row + master_null_bytes;
-    Field **const end_ptr= begin_ptr + colcnt;
-    for (field_ptr= begin_ptr ; field_ptr < end_ptr ; ++field_ptr)
-    {
-      Field *const f= *field_ptr;
-
-      if (bitmap_is_set(cols, field_ptr -  begin_ptr))
-      {
-        ptr= f->unpack(f->ptr + offset, ptr);
-        /* Field...::unpack() cannot return 0 */
-        DBUG_ASSERT(ptr != NULL);
-      }
-      else
-        bitmap_clear_bit(rw_set, field_ptr - begin_ptr);
-    }
+    Field *const f= *field_ptr;
 
-    *row_end = ptr;
-    if (master_reclength)
+    if (bitmap_is_set(cols, field_ptr -  begin_ptr))
     {
-      if (*field_ptr)
-        *master_reclength = (*field_ptr)->ptr - (char*) table->record[0];
-      else
-        *master_reclength = table->s->reclength;
+      ptr= f->unpack(f->ptr + offset, ptr);
+      /* Field...::unpack() cannot return 0 */
+      DBUG_ASSERT(ptr != NULL);
     }
+    else
+      bitmap_clear_bit(rw_set, field_ptr - begin_ptr);
+  }
+
+  *row_end = ptr;
+  if (master_reclength)
+  {
+    if (*field_ptr)
+      *master_reclength = (*field_ptr)->ptr - (char*) table->record[0];
+    else
+      *master_reclength = table->s->reclength;
   }
 
   /*
@@ -5381,16 +5398,26 @@ unpack_row(RELAY_LOG_INFO *rli,
     it was not there already. We iterate over all remaining columns,
     even if there were an error, to get as many error messages as
     possible.  We are still able to return a pointer to the next row,
-    so wedo that.
+    so redo that.
+
+    This generation of error messages is only relevant when inserting
+    new rows.
    */
   for ( ; *field_ptr ; ++field_ptr)
   {
-    if ((*field_ptr)->flags & (NOT_NULL_FLAG | NO_DEFAULT_VALUE_FLAG))
+    uint32 const mask= NOT_NULL_FLAG | NO_DEFAULT_VALUE_FLAG;
+
+    DBUG_PRINT("debug", ("flags = 0x%x, mask = 0x%x, flags & mask = 0x%x",
+                         (*field_ptr)->flags, mask,
+                         (*field_ptr)->flags & mask));
+
+    if (event_type == WRITE_ROWS_EVENT &&
+        ((*field_ptr)->flags & mask) == mask)
     {
-      slave_print_msg(ERROR_LEVEL, rli, ER_NO_DEFAULT_FOR_FIELD, 
+      slave_print_msg(ERROR_LEVEL, rli, ER_NO_DEFAULT_FOR_FIELD,
                       "Field `%s` of table `%s`.`%s` "
                       "has no default value and cannot be NULL",
-                      (*field_ptr)->field_name, table->s->db.str, 
+                      (*field_ptr)->field_name, table->s->db.str,
                       table->s->table_name.str);
       error = ER_NO_DEFAULT_FOR_FIELD;
     }
@@ -5562,8 +5589,8 @@ int Rows_log_event::exec_event(st_relay_log_info *rli)
     {
       char const *row_end= NULL;
       if ((error= do_prepare_row(thd, rli, table, row_start, &row_end)))
-        break; // We should to the after-row operation even in the
-               // case of error
+        break; // We should perform the after-row operation even in
+               // the case of error
       
       DBUG_ASSERT(row_end != NULL); // cannot happen
       DBUG_ASSERT(row_end <= (const char*)m_rows_end);
@@ -6224,7 +6251,7 @@ int Write_rows_log_event::do_prepare_row(THD *thd, RELAY_LOG_INFO *rli,
   error= unpack_row(rli,
                     table, m_width, table->record[0],
                     row_start, &m_cols, row_end, &m_master_reclength,
-                    table->write_set);
+                    table->write_set, WRITE_ROWS_EVENT);
   bitmap_copy(table->read_set, table->write_set);
   return error;
 }
@@ -6285,10 +6312,17 @@ copy_extra_record_fields(TABLE *table,
                          my_size_t master_reclength,
                          my_ptrdiff_t master_fields)
 {
-  DBUG_PRINT("info", ("Copying to %p from field %d at offset %u to field %d at offset %u", 
-                      table->record[0], 
+  DBUG_PRINT("info", ("Copying to %p "
+                      "from field %d at offset %u "
+                      "to field %d at offset %u",
+                      table->record[0],
                       master_fields, master_reclength,
                       table->s->fields, table->s->reclength));
+  /*
+    Copying the extra fields of the slave that does not exist on
+    master into record[0] (which are basically the default values).
+  */
+  DBUG_ASSERT(master_reclength <= table->s->reclength);
   if (master_reclength < table->s->reclength)
     bmove_align(table->record[0] + master_reclength,
                 table->record[1] + master_reclength,
@@ -6771,7 +6805,7 @@ int Delete_rows_log_event::do_prepare_row(THD *thd, RELAY_LOG_INFO *rli,
   error= unpack_row(rli,
                     table, m_width, table->record[0], 
                     row_start, &m_cols, row_end, &m_master_reclength,
-                    table->read_set);
+                    table->read_set, DELETE_ROWS_EVENT);
   /*
     If we will access rows using the random access method, m_key will
     be set to NULL, so we do not need to make a key copy in that case.
@@ -6914,13 +6948,13 @@ int Update_rows_log_event::do_prepare_row(THD *thd, RELAY_LOG_INFO *rli,
   error= unpack_row(rli,
                     table, m_width, table->record[0],
                     row_start, &m_cols, row_end, &m_master_reclength,
-                    table->read_set);
+                    table->read_set, UPDATE_ROWS_EVENT);
   row_start = *row_end;
   /* m_after_image is the after image for the update */
   error= unpack_row(rli,
                     table, m_width, m_after_image,
                     row_start, &m_cols, row_end, &m_master_reclength,
-                    table->write_set);
+                    table->write_set, UPDATE_ROWS_EVENT);
 
   /*
     If we will access rows using the random access method, m_key will
diff --git a/sql/rpl_utility.cc b/sql/rpl_utility.cc
index 5405d022223..c80b6dc3f69 100644
--- a/sql/rpl_utility.cc
+++ b/sql/rpl_utility.cc
@@ -107,11 +107,6 @@ field_length_from_packed(enum_field_types const field_type,
 /*
   Is the definition compatible with a table?
 
-  Compare the definition with a table to see if it is compatible with
-  it.  A table definition is compatible with a table if
-  - the columns types of the table definition is a (not necessarily
-    proper) prefix of the column type of the table, or
-  - the other way around
 */
 int
 table_def::compatible_with(RELAY_LOG_INFO *rli, TABLE *table)
diff --git a/sql/rpl_utility.h b/sql/rpl_utility.h
index 0ac3c10eec6..df0b0cd2ee1 100644
--- a/sql/rpl_utility.h
+++ b/sql/rpl_utility.h
@@ -32,29 +32,95 @@ field_length_from_packed(enum_field_types const field_type,
 
   RESPONSIBILITIES
 
-  - Extract table definition data from the table map event
+  - Extract and decode table definition data from the table map event
   - Check if table definition in table map is compatible with table
     definition on slave
+
+  DESCRIPTION
+
+    Currently, the only field type data available is an array of the
+    type operators that are present in the table map event.
+
+  TODO
+
+    Add type operands to this structure to allow detection of
+    difference between, e.g., BIT(5) and BIT(10).
  */
 
 class table_def
 {
 public:
+  /*
+    Convenience declaration of the type of the field type data in a
+    table map event.
+  */
   typedef unsigned char field_type;
 
-  table_def(field_type *t, my_size_t s)
-    : m_type(t), m_size(s)
+  /*
+    Constructor.
+
+    SYNOPSIS
+      table_def()
+      types Array of types
+      size  Number of elements in array 'types'
+   */
+  table_def(field_type *types, my_size_t size)
+    : m_type(types), m_size(size)
   {
   }
 
+  /*
+    Return the number of fields there is type data for.
+
+    SYNOPSIS
+      size()
+
+    RETURN VALUE
+      The number of fields that there is type data for.
+   */
   my_size_t size() const { return m_size; }
+
+  /*
+    Return a representation of the type data for one field.
+
+    SYNOPSIS
+      type()
+      i   Field index to return data for
+
+    RETURN VALUE
+
+      Will return a representation of the type data for field
+      'i'. Currently, only the type identifier is returned.
+   */
   field_type type(my_ptrdiff_t i) const { return m_type[i]; }
 
+  /*
+    Decide if the table definition is compatible with a table.
+
+    SYNOPSIS
+      compatible_with()
+      rli   Pointer to relay log info
+      table Pointer to table to compare with.
+
+    DESCRIPTION
+
+      Compare the definition with a table to see if it is compatible
+      with it.  A table definition is compatible with a table if:
+
+      - the columns types of the table definition is a (not
+        necessarily proper) prefix of the column type of the table, or
+
+      - the other way around
+
+    RETURN VALUE
+      1  if the table definition is not compatible with 'table'
+      0  if the table definition is compatible with 'table'
+  */
   int compatible_with(RELAY_LOG_INFO *rli, TABLE *table) const;
 
 private:
-  my_size_t m_size;
-  field_type *m_type;
+  my_size_t m_size;           // Number of elements in the types array
+  field_type *m_type;                     // Array of type descriptors
 };
 
 #endif /* RPL_UTILITY_H */