BUG#11882110: UPDATE REPORTS ER_KEY_NOT_FOUND IF TABLE IS

              UPDATED TWICE

For multi update it is not allowed to update a column
of a table if that table is accessed through multiple aliases
and either
1) the updated column is used as partitioning key
2) the updated column is part of the primary key 
   and the primary key is clustered

This check is done in unsafe_key_update().

The bug was that for case 2), it was checked whether
updated_column_number == table_share->primary_key 
However, the primary_key variable is the index number of the 
primary key, not a column number.

Prior to this bugfix, the first column was wrongly believed to be
the primary key. The columns covered by an index is found in
table->key_info[idx_number]->key_part. The bugfix is to check if
any of the columns in the keyparts of the primary key are
updated.

The user-visible effect is that for storage engines with
clustered primary key (e.g. InnoDB but not MyISAM) queries
like 
"UPDATE t1 AS A JOIN t2 AS B SET A.primkey=..."
will now error with 
"ERROR HY000: Primary key/partition key update is not allowed 
since the table is updated both as 'A' and 'B'." 
instead of 
"ERROR 1032 (HY000): Can't find record in 't1_tb'"
even if primkey is not the first column in the table. This 
was the intended behavior of bugfix 11764529.


mysql-test/r/multi_update.result:
  Add test for bug#11882110
mysql-test/r/multi_update_innodb.result:
  Add test for bug#11882110
mysql-test/t/multi_update.test:
  Add test for bug#11882110
mysql-test/t/multi_update_innodb.test:
  Add test for bug#11882110
sql/sql_update.cc:
  unsafe_key_update() wrongly checked if the primary key index
  number was the same as updated column number. Now it is checked
  whether any of the columns making up the primary key is updated.
sql/table.h:
  Fix comment on TABLE_SHARE::primary_key. Incorrect comment
  was introduced by an earlier merge conflict (as per dlenev)

2 files changed, 91 insertions, 1 deletions

diff --git a/mysql-test/t/multi_update.test b/mysql-test/t/multi_update.test
index 496d045075a..4de574fbb0d 100644
--- a/mysql-test/t/multi_update.test
+++ b/mysql-test/t/multi_update.test
@@ -703,4 +703,50 @@ UPDATE t1 AS A, t1 AS B SET A.pk = 1, B.a = 2;
 SELECT * FROM t1;
 DROP TABLE t1;
 
---echo end of tests
+--echo #
+--echo # BUG#11882110: UPDATE REPORTS ER_KEY_NOT_FOUND IF TABLE IS 
+--echo #               UPDATED TWICE
+--echo #
+
+# Results differ between storage engines. This test is to verify that
+# the bugfix did NOT change behavior for MyISAM.
+# See multi_update_innodb.test for the InnoDB variant of this test
+CREATE TABLE t1 ( 
+  col_int_key int, 
+  pk int, 
+  col_int int, 
+  key(col_int_key), 
+  primary key (pk)
+) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,2,3);
+
+--echo
+CREATE TABLE t2 ( 
+  col_int_key int, 
+  pk_1 int, 
+  pk_2 int, 
+  col_int int, 
+  key(col_int_key), 
+  primary key (pk_1,pk_2)
+) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1,2,3,4);
+
+--echo
+UPDATE t1 AS A NATURAL JOIN t1 B SET A.pk=5,B.pk=7;
+
+--echo
+SELECT * FROM t1;
+
+--echo
+UPDATE t2 AS A NATURAL JOIN t2 B SET A.pk_1=5,B.pk_1=7;
+--echo
+UPDATE t2 AS A NATURAL JOIN t2 B SET A.pk_2=10,B.pk_2=11;
+
+--echo
+SELECT * FROM t2;
+
+DROP TABLE t1,t2;
+
+
+
+
diff --git a/mysql-test/t/multi_update_innodb.test b/mysql-test/t/multi_update_innodb.test
index 3148d009cef..51757c29553 100644
--- a/mysql-test/t/multi_update_innodb.test
+++ b/mysql-test/t/multi_update_innodb.test
@@ -31,3 +31,47 @@ SELECT * FROM t1;
 DROP VIEW v1;
 DROP TABLE t1;
 
+--echo #
+--echo # BUG#11882110: UPDATE REPORTS ER_KEY_NOT_FOUND IF TABLE IS 
+--echo #               UPDATED TWICE
+--echo #
+
+# Results differ between storage engines.
+# See multi_update.test for the MyISAM variant of this test
+CREATE TABLE t1 ( 
+  col_int_key int, 
+  pk int, 
+  col_int int, 
+  key(col_int_key), 
+  primary key (pk)
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES (1,2,3);
+
+--echo
+CREATE TABLE t2 ( 
+  col_int_key int, 
+  pk_1 int, 
+  pk_2 int, 
+  col_int int, 
+  key(col_int_key), 
+  primary key (pk_1,pk_2)
+) ENGINE=InnoDB;
+INSERT INTO t2 VALUES (1,2,3,4);
+
+--echo
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t1 AS A NATURAL JOIN t1 B SET A.pk=5,B.pk=7;
+--echo
+SELECT * FROM t1;
+
+--echo
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t2 AS A NATURAL JOIN t2 B SET A.pk_1=5,B.pk_1=7;
+--echo
+--error ER_MULTI_UPDATE_KEY_CONFLICT
+UPDATE t2 AS A NATURAL JOIN t2 B SET A.pk_2=10,B.pk_2=11;
+
+--echo
+SELECT * FROM t2;
+
+DROP TABLE t1,t2;