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Bug #53830: !table || (!table->read_set ||

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bitmap_is_set(table->read_set, field_index))

UPDATE on an InnoDB table modifying the same index that is used
to satisfy the WHERE condition could trigger a debug assertion
under some circumstances.

Since for engines with the HA_PRIMARY_KEY_IN_READ_INDEX flag
set results of an index scan on a secondary index are appended
by the primary key value, if a query involves only columns from
the primary key and a secondary index, the latter is considered
to be covering.

That tricks mysql_update() to mark for reading only columns
from the secondary index when it does an index scan to retrieve
rows to update in case a part of that key is also being
updated. However, there may be other columns in WHERE that are
part of the primary key, but not the secondary one.

What we actually want to do in this case is to add index
columns to the existing WHERE columns bitmap rather than
replace it.

mysql-test/r/innodb_mysql.result:
  Test case for bug #53830.
mysql-test/t/innodb_mysql.test:
  Test case for bug #53830.
sql/sql_update.cc:
  Add index columns to the read_set bitmap, don't replace it.
sql/table.cc:
  Added a new add_read_columns_used_by_index() function to 
  st_table.
sql/table.h:
  Added a new add_read_columns_used_by_index() function to 
  st_table.
This commit is contained in:
Alexey Kopytov
2010-05-25 18:43:45 +04:00
parent d72a4710aa
commit 1d0acc7754
5 changed files with 46 additions and 1 deletions
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9
mysql-test/r/innodb_mysql.result
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@ -2408,4 +2408,13 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 const PRIMARY NULL NULL NULL 1 Impossible ON condition
1 SIMPLE t2 ALL NULL NULL NULL NULL 3 Using where
DROP TABLE t1,t2;
#
# Bug #53830: !table || (!table->read_set || bitmap_is_set(table->read_set, field_index))
#
CREATE TABLE t1 (a INT, b INT, c INT, d INT,
PRIMARY KEY(a,b,c), KEY(b,d))
ENGINE=InnoDB;
INSERT INTO t1 VALUES (0, 77, 1, 3);
UPDATE t1 SET d = 0 WHERE b = 77 AND c = 25;
DROP TABLE t1;
End of 5.1 tests