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Bug#16691598 - ORDER BY LOWER(COLUMN) PRODUCES OUT-OF-ORDER RESULTS

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Problem:-
We have created a table with UTF8_BIN collation.
In case, when in our query we have ORDER BY clause over a function 
call we are getting result in incorrect order.
Note:the bug is not there in 5.5.

Analysis:
In 5.5, for UTF16_BIN, we have min and max multi-byte length is 2 and 4 
respectively.In make_sortkey(),for 2 byte character character we are 
assuming that the resultant length will be 2 byte/character. But when we 
use my_strnxfrm_unicode_full_bin(), we store sorting weights using 3 bytes 
per character.This result in truncated result.

Same thing happen for UTF8MB4, where we have 1 byte min multi-byte and 
4 byte max multi-byte.We will accsume resultant data as 1 byte/character, 
which result in truncated result.

Solution:-
use strnxfrm(means use of MY_CS_STRNXFRM macro) is used for sort, in 
which the resultant length is not dependent on source length.
This commit is contained in:
Neeraj Bisht 2013-11-07 16:46:24 +05:30
parent e6949c24f4
commit 88680a99c6
7 changed files with 74 additions and 17 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
mysql-test/include/ctype_filesort2.inc
View file

@ -14,3 +14,12 @@ SELECT HEX(a), HEX(CONVERT(a USING utf8mb4)) FROM t1 ORDER BY a;
ALTER TABLE t1 ADD KEY(a);
SELECT HEX(a), HEX(CONVERT(a USING utf8mb4)) FROM t1 ORDER BY a;
DROP TABLE IF EXISTS t1;
--echo #
--echo # BUG#16691598 - ORDER BY LOWER(COLUMN) PRODUCES
--echo # OUT-OF-ORDER RESULTS
--echo #
CREATE TABLE t1 SELECT ('a a') as n;
INSERT INTO t1 VALUES('a b');
SELECT * FROM t1 ORDER BY LOWER(n) ASC;
SELECT * FROM t1 ORDER BY LOWER(n) DESC;
DROP TABLE t1;

15
mysql-test/r/ctype_utf16.result
View file

@ -636,6 +636,21 @@ FF9D EFBE9D
D800DF84 F0908E84
DBC0DC00 F4808080
DROP TABLE IF EXISTS t1;
#
# BUG#16691598 - ORDER BY LOWER(COLUMN) PRODUCES
# OUT-OF-ORDER RESULTS
#
CREATE TABLE t1 SELECT ('a a') as n;
INSERT INTO t1 VALUES('a b');
SELECT * FROM t1 ORDER BY LOWER(n) ASC;
n
a a
a b
SELECT * FROM t1 ORDER BY LOWER(n) DESC;
n
a b
a a
DROP TABLE t1;
select @@collation_connection;
@@collation_connection
utf16_bin

15
mysql-test/r/ctype_utf32.result
View file

@ -635,6 +635,21 @@ HEX(a) HEX(CONVERT(a USING utf8mb4))
00010384 F0908E84
00100000 F4808080
DROP TABLE IF EXISTS t1;
#
# BUG#16691598 - ORDER BY LOWER(COLUMN) PRODUCES
# OUT-OF-ORDER RESULTS
#
CREATE TABLE t1 SELECT ('a a') as n;
INSERT INTO t1 VALUES('a b');
SELECT * FROM t1 ORDER BY LOWER(n) ASC;
n
a a
a b
SELECT * FROM t1 ORDER BY LOWER(n) DESC;
n
a b
a a
DROP TABLE t1;
select @@collation_connection;
@@collation_connection
utf32_bin

15
mysql-test/r/ctype_utf8mb4.result
View file

@ -1012,6 +1012,21 @@ EFBE9D EFBE9D
F0908E84 F0908E84
F4808080 F4808080
DROP TABLE IF EXISTS t1;
#
# BUG#16691598 - ORDER BY LOWER(COLUMN) PRODUCES
# OUT-OF-ORDER RESULTS
#
CREATE TABLE t1 SELECT ('a a') as n;
INSERT INTO t1 VALUES('a b');
SELECT * FROM t1 ORDER BY LOWER(n) ASC;
n
a a
a b
SELECT * FROM t1 ORDER BY LOWER(n) DESC;
n
a b
a a
DROP TABLE t1;
select @@collation_connection;
@@collation_connection
utf8mb4_bin

32
sql/filesort.cc
View file

@ -813,8 +813,6 @@ static void make_sortkey(register SORTPARAM *param,
{
CHARSET_INFO *cs=item->collation.collation;
char fill_char= ((cs->state & MY_CS_BINSORT) ? (char) 0 : ' ');
int diff;
uint sort_field_length;
if (maybe_null)
*to++=1;
@ -842,25 +840,13 @@ static void make_sortkey(register SORTPARAM *param,
break;
}
length= res->length();
sort_field_length= sort_field->length - sort_field->suffix_length;
diff=(int) (sort_field_length - length);
if (diff < 0)
{
diff=0;
length= sort_field_length;
}
if (sort_field->suffix_length)
{
/* Store length last in result_string */
store_length(to + sort_field_length, length,
sort_field->suffix_length);
}
if (sort_field->need_strxnfrm)
{
char *from=(char*) res->ptr();
uint tmp_length;
if ((uchar*) from == to)
{
DBUG_ASSERT(sort_field->length >= length);
set_if_smaller(length,sort_field->length);
memcpy(param->tmp_buffer,from,length);
from=param->tmp_buffer;
@ -871,6 +857,22 @@ static void make_sortkey(register SORTPARAM *param,
}
else
{
uint diff;
uint sort_field_length= sort_field->length -
sort_field->suffix_length;
if (sort_field_length < length)
{
diff= 0;
length= sort_field_length;
}
else
diff= sort_field_length - length;
if (sort_field->suffix_length)
{
/* Store length last in result_string */
store_length(to + sort_field_length, length,
sort_field->suffix_length);
}
my_strnxfrm(cs,(uchar*)to,length,(const uchar*)res->ptr(),length);
cs->cset->fill(cs, (char *)to+length,diff,fill_char);
}

2
strings/ctype-ucs2.c
View file

@ -1664,7 +1664,7 @@ CHARSET_INFO my_charset_utf16_general_ci=
CHARSET_INFO my_charset_utf16_bin=
{
55,0,0, /* number */
MY_CS_COMPILED|MY_CS_BINSORT|MY_CS_UNICODE|MY_CS_NONASCII,
MY_CS_COMPILED|MY_CS_BINSORT|MY_CS_STRNXFRM|MY_CS_UNICODE|MY_CS_NONASCII,
"utf16", /* cs name */
"utf16_bin", /* name */
"UTF-16 Unicode", /* comment */

3
strings/ctype-utf8.c
View file

@ -5435,7 +5435,8 @@ CHARSET_INFO my_charset_utf8mb4_general_ci=
CHARSET_INFO my_charset_utf8mb4_bin=
{
46,0,0, /* number */
MY_CS_COMPILED|MY_CS_BINSORT|MY_CS_UNICODE|MY_CS_UNICODE_SUPPLEMENT, /* state */
MY_CS_COMPILED|MY_CS_BINSORT|MY_CS_STRNXFRM|MY_CS_UNICODE|
MY_CS_UNICODE_SUPPLEMENT, /* state */
MY_UTF8MB4, /* cs name */
MY_UTF8MB4_BIN, /* name */
"UTF-8 Unicode", /* comment */