Commit cd1b00e8 authored by istruewing@stella.local's avatar istruewing@stella.local
Browse files

Bug#32705 - myisam corruption: Key in wrong position 

            at page 1024 with ucs2_bin

Inserting strings with a common prefix into a table with
characterset UCS2 corrupted the table.

An efficient search method was used, which compares end space
with ASCII blank. This doesn't work for character sets like UCS2,
which do not encode blank like ASCII does.

Use the less efficient search method _mi_seq_search()
for charsets with mbminlen > 1.
parent 9217f011

myisam/mi_open.c

+10 −1
Original line number Diff line number Diff line
@@ -791,8 +791,17 @@ static void setup_key_functions(register MI_KEYDEF *keyinfo) 
    keyinfo->get_key= _mi_get_pack_key;

    if (keyinfo->seg[0].flag & HA_PACK_KEY)

    {						/* Prefix compression */

      /*

        _mi_prefix_search() compares end-space against ASCII blank (' ').

        It cannot be used for character sets, that do not encode the

        blank character like ASCII does. UCS2 is an example. All

        character sets with a fixed width > 1 or a mimimum width > 1

        cannot represent blank like ASCII does. In these cases we have

        to use _mi_seq_search() for the search.

      */

      if (!keyinfo->seg->charset || use_strnxfrm(keyinfo->seg->charset) ||

          (keyinfo->seg->flag & HA_NULL_PART))

          (keyinfo->seg->flag & HA_NULL_PART) ||

          (keyinfo->seg->charset->mbminlen > 1))

        keyinfo->bin_search=_mi_seq_search;

      else

        keyinfo->bin_search=_mi_prefix_search;

mysql-test/r/myisam.result

+10 −0
Original line number Diff line number Diff line
@@ -1839,4 +1839,14 @@ CHECK TABLE t1 EXTENDED; 
Table	Op	Msg_type	Msg_text

test.t1	check	status	OK

DROP TABLE t1;

CREATE TABLE t1 (

c1 CHAR(255) CHARACTER SET UCS2 COLLATE UCS2_BIN NOT NULL,

KEY(c1)

) ENGINE=MyISAM;

INSERT INTO t1 VALUES ('marshall\'s');

INSERT INTO t1 VALUES ('marsh');

CHECK TABLE t1 EXTENDED;

Table	Op	Msg_type	Msg_text

test.t1	check	status	OK

DROP TABLE t1;

End of 5.0 tests

mysql-test/t/myisam.test

+13 −0
Original line number Diff line number Diff line
@@ -1193,4 +1193,17 @@ SET @@myisam_repair_threads=1; 
CHECK TABLE t1 EXTENDED;

DROP TABLE t1;



#

# Bug#32705 - myisam corruption: Key in wrong position

#             at page 1024 with ucs2_bin

#

CREATE TABLE t1 (

  c1 CHAR(255) CHARACTER SET UCS2 COLLATE UCS2_BIN NOT NULL,

  KEY(c1)

  ) ENGINE=MyISAM;

INSERT INTO t1 VALUES ('marshall\'s');

INSERT INTO t1 VALUES ('marsh');

CHECK TABLE t1 EXTENDED;

DROP TABLE t1;



--echo End of 5.0 tests