BUG#11762751: UPDATE STATEMENT THROWS AN ERROR, BUT STILL

UPDATES THE TABLE ENTRIES (formerly 55385)
BUG#11764529: MULTI UPDATE+INNODB REPORTS ER_KEY_NOT_FOUND 
              IF A TABLE IS UPDATED TWICE (formerly 57373)
            
If multiple-table update updates a row through two aliases and
the first update physically moves the row, the second update will
fail to locate the row. This results in different errors
depending on storage engine:
  * MyISAM: Got error 134 from storage engine
  * InnoDB: Can't find record in 'tbl'
None of these errors accurately describe the problem. 
      
Furthermore, since MyISAM is non-transactional, the update
executed first will be performed while the second will not.
In addition, for two equal multiple-table update statements,
one could succeed and the other fail based on whether or not
the record actually moved or not. This was inconsistent.
      
Two update operations may physically move a row:
  1) Update of a column in a clustered primary key
  2) Update of a column used to calculate which partition the 
     row belongs to
           
BUG#11764529 is about case 1) above, BUG#11762751 was about case 2).
      
The fix for these bugs is to return with an error if multiple-table 
update is about to:
  a) Update a table through multiple aliases, and
  b) Perform an update that may physically more the row 
     in at least one of these aliases
    
This avoids 
  * partial updates as described for MyISAM above,
  * provides the same error message that describes the actual problem
    for all SEs
  * inconsistent behavior where a statement fails or succeeds based on
    e.g. the partitioning algorithm of the table.

mysql-test/r/multi_update.result:
  Add test for bug#57373
mysql-test/r/multi_update_innodb.result:
  Add test for bug#57373
mysql-test/r/partition.result:
  Add test for bug#55385
mysql-test/t/multi_update.test:
  Add test for bug#57373
mysql-test/t/multi_update_innodb.test:
  Add test for bug#57373
mysql-test/t/partition.test:
  Add test for bug#55385
sql/handler.cc:
  Translate handler error HA_ERR_RECORD_DELETED to server error
sql/share/errmsg-utf8.txt:
  New error message for multi-table update where the same table is updated multiple times.
sql/sql_update.cc:
  Add function unsafe_key_update()

mysql-test/r/multi_update.result

@@ -680,4 +680,21 @@ Warnings:
 Warning	1292	Truncated incorrect datetime value: '1'
 DROP FUNCTION f1;
 DROP TABLE t1;
+#
+# BUG#57373: Multi update+InnoDB reports ER_KEY_NOT_FOUND if a
+#            table is updated twice
+#
+CREATE TABLE t1(
+pk INT,
+a INT,
+PRIMARY KEY (pk)
+) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (0,0);
+UPDATE t1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
+
+# Should be (1,2)
+SELECT * FROM t1;
+pk	a
+1	2
+DROP TABLE t1;
 end of tests

mysql-test/r/multi_update_innodb.result

@@ -0,0 +1,29 @@
+#
+# BUG#57373: Multi update+InnoDB reports ER_KEY_NOT_FOUND if a
+#            table is updated twice
+#
+CREATE TABLE t1(
+pk INT,
+a INT,
+b INT,
+PRIMARY KEY (pk)
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (0,0,0);
+UPDATE t1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
+ERROR HY000: Primary key/partition key update is not allowed since the table is updated both as 'A' and 'B'.
+SELECT * FROM t1;
+pk	a	b
+0	0	0
+CREATE VIEW v1 AS SELECT * FROM t1;
+UPDATE v1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
+ERROR HY000: Primary key/partition key update is not allowed since the table is updated both as 'A' and 'B'.
+SELECT * FROM t1;
+pk	a	b
+0	0	0
+UPDATE t1 AS A, t1 AS B SET A.a = 1, B.b = 2;
+# Should be (0,1,2)
+SELECT * FROM t1;
+pk	a	b
+0	1	2
+DROP VIEW v1;
+DROP TABLE t1;

mysql-test/r/partition.result

@@ -2264,3 +2264,51 @@ INSERT INTO t1 VALUES(0);
 DROP TABLE t1;
 SET GLOBAL myisam_use_mmap=default;
 End of 5.1 tests
+#
+# BUG#55385: UPDATE statement throws an error, but still updates
+#            the table entries
+CREATE TABLE t1_part (
+partkey int,
+nokey int
+) PARTITION BY LINEAR HASH(partkey) PARTITIONS 3;
+INSERT INTO t1_part VALUES (1, 1) , (10, 10);
+CREATE VIEW v1 AS SELECT * FROM t1_part;
+
+# Should be (1,1),(10,10)
+SELECT * FROM t1_part;
+partkey	nokey
+1	1
+10	10
+
+# Case 1
+# Update is refused because partitioning key is updated
+UPDATE t1_part AS A NATURAL JOIN t1_part B SET A.partkey = 2, B.nokey = 3;
+ERROR HY000: Primary key/partition key update is not allowed since the table is updated both as 'A' and 'B'.
+UPDATE t1_part AS A NATURAL JOIN t1_part B SET A.nokey = 2, B.partkey = 3;
+ERROR HY000: Primary key/partition key update is not allowed since the table is updated both as 'A' and 'B'.
+
+# Case 2
+# Like 1, but partition accessed through a view
+UPDATE t1_part AS A NATURAL JOIN v1 as B SET A.nokey = 2 , B.partkey = 3;
+ERROR HY000: Primary key/partition key update is not allowed since the table is updated both as 'A' and 'B'.
+UPDATE v1 AS A NATURAL JOIN t1_part as B SET A.nokey = 2 , B.partkey = 3;
+ERROR HY000: Primary key/partition key update is not allowed since the table is updated both as 'A' and 'B'.
+
+# Should be (1,1),(10,10)
+SELECT * FROM t1_part;
+partkey	nokey
+1	1
+10	10
+
+# Case 3
+# Update is accepted because partitioning key is not updated
+UPDATE t1_part AS A NATURAL JOIN t1_part B SET A.nokey = 2 , B.nokey = 3;
+
+# Should be (1,3),(10,3)
+SELECT * FROM t1_part;
+partkey	nokey
+1	3
+10	3
+
+DROP VIEW v1;
+DROP TABLE t1_part;

mysql-test/t/multi_update.test

@@ -683,4 +683,24 @@ UPDATE (SELECT 1 FROM t1 WHERE f1 = (SELECT f1() FROM t1)) x, t1 SET f1 = 1;
 DROP FUNCTION f1;
 DROP TABLE t1;
 
+--echo #
+--echo # BUG#57373: Multi update+InnoDB reports ER_KEY_NOT_FOUND if a
+--echo #            table is updated twice
+--echo #
+
+# Results differ between storage engines.
+# See multi_update_innodb.test for the InnoDB variant of this test
+CREATE TABLE t1(
+  pk INT,
+  a INT,
+  PRIMARY KEY (pk)
+) ENGINE=MyISAM;
+
+INSERT INTO t1 VALUES (0,0);
+UPDATE t1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
+--echo
+--echo # Should be (1,2)
+SELECT * FROM t1;
+DROP TABLE t1;
+
 --echo end of tests

mysql-test/t/multi_update_innodb.test

@@ -0,0 +1,33 @@
+--source include/have_innodb.inc
+
+--echo #
+--echo # BUG#57373: Multi update+InnoDB reports ER_KEY_NOT_FOUND if a
+--echo #            table is updated twice
+--echo #
+
+# Results differ between storage engines.
+# See multi_update.test for the MyISAM variant of this test
+CREATE TABLE t1(
+  pk INT,
+  a INT,
+  b INT,
+  PRIMARY KEY (pk)
+) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES (0,0,0);
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
+SELECT * FROM t1;
+
+CREATE VIEW v1 AS SELECT * FROM t1;
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE v1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
+SELECT * FROM t1;
+
+UPDATE t1 AS A, t1 AS B SET A.a = 1, B.b = 2;
+--echo # Should be (0,1,2)
+SELECT * FROM t1;
+
+DROP VIEW v1;
+DROP TABLE t1;
+

mysql-test/t/partition.test

@@ -2267,3 +2267,53 @@ DROP TABLE t1;
 SET GLOBAL myisam_use_mmap=default;
 
 --echo End of 5.1 tests
+
+--echo #
+--echo # BUG#55385: UPDATE statement throws an error, but still updates
+--echo #            the table entries
+
+CREATE TABLE t1_part (
+  partkey int,
+  nokey int
+) PARTITION BY LINEAR HASH(partkey) PARTITIONS 3;
+
+INSERT INTO t1_part VALUES (1, 1) , (10, 10);
+CREATE VIEW v1 AS SELECT * FROM t1_part;
+
+--echo
+--echo # Should be (1,1),(10,10)
+SELECT * FROM t1_part;
+
+--echo
+--echo # Case 1
+--echo # Update is refused because partitioning key is updated
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t1_part AS A NATURAL JOIN t1_part B SET A.partkey = 2, B.nokey = 3;
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t1_part AS A NATURAL JOIN t1_part B SET A.nokey = 2, B.partkey = 3;
+
+--echo
+--echo # Case 2
+--echo # Like 1, but partition accessed through a view
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t1_part AS A NATURAL JOIN v1 as B SET A.nokey = 2 , B.partkey = 3;
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE v1 AS A NATURAL JOIN t1_part as B SET A.nokey = 2 , B.partkey = 3;
+
+--echo
+--echo # Should be (1,1),(10,10)
+SELECT * FROM t1_part;
+
+--echo
+--echo # Case 3
+--echo # Update is accepted because partitioning key is not updated
+UPDATE t1_part AS A NATURAL JOIN t1_part B SET A.nokey = 2 , B.nokey = 3;
+
+--echo
+--echo # Should be (1,3),(10,3)
+SELECT * FROM t1_part;
+
+--echo
+# Cleanup
+DROP VIEW v1;
+DROP TABLE t1_part;

sql/handler.cc

@@ -2700,6 +2700,7 @@ void handler::print_error(int error, myf errflag)
     break;
   case HA_ERR_KEY_NOT_FOUND:
   case HA_ERR_NO_ACTIVE_RECORD:
+  case HA_ERR_RECORD_DELETED:
   case HA_ERR_END_OF_FILE:
     textno=ER_KEY_NOT_FOUND;
     break;

sql/share/errmsg-utf8.txt

@@ -6394,3 +6394,6 @@ ER_SLAVE_HEARTBEAT_VALUE_OUT_OF_RANGE_MAX
 
 ER_STMT_CACHE_FULL  
         eng "Multi-row statements required more than 'max_binlog_stmt_cache_size' bytes of storage; increase this mysqld variable and try again"
+
+ER_MULTI_UPDATE_KEY_CONFLICT
+  eng "Primary key/partition key update is not allowed since the table is updated both as '%-.192s' and '%-.192s'."

sql/sql_update.cc

@@ -998,6 +998,98 @@ static table_map get_table_map(List<Item> *items)
   return map;
 }
 
+/**
+  If one row is updated through two different aliases and the first
+  update physically moves the row, the second update will error
+  because the row is no longer located where expected. This function
+  checks if the multiple-table update is about to do that and if so
+  returns with an error.
+
+  The following update operations physically moves rows:
+    1) Update of a column in a clustered primary key
+    2) Update of a column used to calculate which partition the row belongs to
+
+  This function returns with an error if both of the following are
+  true:
+
+    a) A table in the multiple-table update statement is updated
+       through multiple aliases (including views)
+    b) At least one of the updates on the table from a) may physically
+       moves the row. Note: Updating a column used to calculate which
+       partition a row belongs to does not necessarily mean that the
+       row is moved. The new value may or may not belong to the same
+       partition.
+
+  @param leaves               First leaf table
+  @param tables_for_update    Map of tables that are updated
+
+  @return
+    true   if the update is unsafe, in which case an error message is also set,
+    false  otherwise.
+*/
+static
+bool unsafe_key_update(TABLE_LIST *leaves, table_map tables_for_update)
+{
+  TABLE_LIST *tl= leaves;
+
+  for (tl= leaves; tl ; tl= tl->next_leaf)
+  {
+    if (tl->table->map & tables_for_update)
+    {
+      TABLE *table1= tl->table;
+      bool primkey_clustered= (table1->file->primary_key_is_clustered() &&
+                               table1->s->primary_key != MAX_KEY);
+
+      bool table_partitioned= false;
+#ifdef WITH_PARTITION_STORAGE_ENGINE
+      table_partitioned= (table1->part_info != NULL);
+#endif
+
+      if (!table_partitioned && !primkey_clustered)
+        continue;
+
+      for (TABLE_LIST* tl2= tl->next_leaf; tl2 ; tl2= tl2->next_leaf)
+      {
+        /*
+          Look at "next" tables only since all previous tables have
+          already been checked
+        */
+        TABLE *table2= tl2->table;
+        if (table2->map & tables_for_update && table1->s == table2->s)
+        {
+          // A table is updated through two aliases
+          if (table_partitioned &&
+              (partition_key_modified(table1, table1->write_set) ||
+               partition_key_modified(table2, table2->write_set)))
+          {
+            // Partitioned key is updated
+            my_error(ER_MULTI_UPDATE_KEY_CONFLICT, MYF(0),
+                     tl->belong_to_view ? tl->belong_to_view->alias
+                                        : tl->alias,
+                     tl2->belong_to_view ? tl2->belong_to_view->alias
+                                         : tl2->alias);
+            return true;
+          }
+
+          if (primkey_clustered &&
+              (bitmap_is_set(table1->write_set, table1->s->primary_key) ||
+               bitmap_is_set(table2->write_set, table2->s->primary_key)))
+          {
+            // Clustered primary key is updated
+            my_error(ER_MULTI_UPDATE_KEY_CONFLICT, MYF(0),
+                     tl->belong_to_view ? tl->belong_to_view->alias
+                                        : tl->alias,
+                     tl2->belong_to_view ? tl2->belong_to_view->alias
+                                         : tl2->alias);
+            return true;
+          }
+        }
+      }
+    }
+  }
+  return false;
+}
+
 
 /*
   make update specific preparation and checks after opening tables
@@ -1077,10 +1169,14 @@ int mysql_multi_update_prepare(THD *thd)
 
   thd->table_map_for_update= tables_for_update= get_table_map(fields);
 
+  leaves= lex->select_lex.leaf_tables;
+
+  if (unsafe_key_update(leaves, tables_for_update))
+    DBUG_RETURN(true);
+
   /*
     Setup timestamp handling and locking mode
   */
-  leaves= lex->select_lex.leaf_tables;
   for (tl= leaves; tl; tl= tl->next_leaf)
   {
     TABLE *table= tl->table;