BUG#17994219: CREATE TABLE .. SELECT PRODUCES INVALID STRUCTURE,

BREAKS RBR

Analysis:
--------
A table created using a query of the format:
CREATE TABLE t1 AS SELECT REPEAT('A',1000) DIV 1 AS a;
breaks the Row Based Replication.

The query above creates a table having a field of datatype
'bigint' with a display width of 3000 which is beyond the
maximum acceptable value of 255.

In the RBR mode, CREATE TABLE SELECT statement is
replicated as a combination of CREATE TABLE statement
equivalent to one the returned by SHOW CREATE TABLE and
row events for rows inserted. When this CREATE TABLE event
is executed on the slave, an error is reported:
Display width out of range for column 'a' (max = 255)

The following is the output of 'SHOW CREATE TABLE t1':
CREATE TABLE t1(`a` bigint(3000) DEFAULT NULL)
                  ENGINE=InnoDB DEFAULT CHARSET=latin1;

The problem is due to the combination of two facts:

1) The above CREATE TABLE SELECT statement uses the display
   width of the result of DIV operation as the display width
   of the column created without validating the width for out
   of bound condition.
2) The DIV operation incorrectly returns the length of its first
   argument as the display width of its result; thus allowing
   creation of a table with an incorrect display width of 3000
   for the field.

Fix:
----
This fix changes the DIV operation implementation to correctly
evaluate the display width of its result. We check if DIV's
results estimated width crosses maximum width for integer
value (21) and if yes set it to this maximum value.

This patch also fixes fixes maximum display width evaluation
for DIV function when its first argument is in UCS2.
This commit is contained in:
Nisha Gopalakrishnan 2014-04-28 16:28:09 +05:30
parent 23f576b539
commit b34d3728dd
3 changed files with 62 additions and 4 deletions

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@ -0,0 +1,28 @@
include/master-slave.inc
[connection master]
#
# BUG#17994219: CREATE TABLE .. SELECT PRODUCES INVALID STRUCTURE,
# BREAKS RBR
#
#After the patch, the display width is set to a default
#value of 21.
CREATE TABLE t1 AS SELECT REPEAT('A', 1000) DIV 1 AS a;
Warnings:
Warning 1366 Incorrect decimal value: '' for column '' at row -1
SHOW CREATE TABLE t1;
Table Create Table
t1 CREATE TABLE `t1` (
`a` bigint(21) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
CREATE TABLE t2 AS SELECT CONVERT(REPEAT('A', 255) USING UCS2) DIV 1 AS a;
Warnings:
Warning 1366 Incorrect decimal value: '' for column '' at row -1
SHOW CREATE TABLE t2;
Table Create Table
t2 CREATE TABLE `t2` (
`a` bigint(21) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
#After the patch, no error is reported.
DROP TABLE t1;
DROP TABLE t2;
include/rpl_end.inc

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@ -0,0 +1,28 @@
# Testing table creations for row-based replication.
--source include/have_binlog_format_row.inc
--source include/master-slave.inc
--echo #
--echo # BUG#17994219: CREATE TABLE .. SELECT PRODUCES INVALID STRUCTURE,
--echo # BREAKS RBR
--echo #
connection master;
--echo #After the patch, the display width is set to a default
--echo #value of 21.
CREATE TABLE t1 AS SELECT REPEAT('A', 1000) DIV 1 AS a;
SHOW CREATE TABLE t1;
CREATE TABLE t2 AS SELECT CONVERT(REPEAT('A', 255) USING UCS2) DIV 1 AS a;
SHOW CREATE TABLE t2;
--echo #After the patch, no error is reported.
sync_slave_with_master;
connection master;
DROP TABLE t1;
DROP TABLE t2;
--source include/rpl_end.inc

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@ -1,4 +1,4 @@
/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -1649,9 +1649,11 @@ void Item_func_int_div::fix_length_and_dec()
{
Item_result argtype= args[0]->result_type();
/* use precision ony for the data type it is applicable for and valid */
max_length=args[0]->max_length -
(argtype == DECIMAL_RESULT || argtype == INT_RESULT ?
args[0]->decimals : 0);
uint32 char_length= args[0]->max_char_length() -
(argtype == DECIMAL_RESULT || argtype == INT_RESULT ?
args[0]->decimals : 0);
fix_char_length(char_length > MY_INT64_NUM_DECIMAL_DIGITS ?
MY_INT64_NUM_DECIMAL_DIGITS : char_length);
maybe_null=1;
unsigned_flag=args[0]->unsigned_flag | args[1]->unsigned_flag;
}