Commit b50d4476 authored by unknown's avatar unknown
Browse files

Fixed unique prefix key bug for multibyte character sets (BUG #4521) for 

InnoDB. This fixes also a second part of the same problem with prefix keys
on a multibyte string column for InnoDB.


innobase/rem/rem0cmp.c:
  Fixed unique prefix key or prefix key using multibyte character set bugs for
  InnoDB (BUG #4521).
  
  The unique key with a prefix of N appears index 3*N bytes of the column not N
  characters. If you had two records which have the same first N characters 
  but differ in the first 3*N bytes, then you couldn't select the records using 
  an equality test.
parent 094c9f32

innobase/rem/rem0cmp.c

+31 −0
Original line number Diff line number Diff line
@@ -14,6 +14,9 @@ Created 7/1/1994 Heikki Tuuri 


#include "srv0srv.h"



#include <m_ctype.h>

#include <my_sys.h>



/*		ALPHABETICAL ORDER

		==================
@@ -453,6 +456,8 @@ cmp_dtuple_rec_with_match( 
					in current field */

	int		ret = 3333;	/* return value */

	

	CHARSET_INFO*   charset;        /* charset used in the field */



	ut_ad(dtuple && rec && matched_fields && matched_bytes);

	ut_ad(dtuple_check_typed(dtuple));
@@ -541,6 +546,32 @@ cmp_dtuple_rec_with_match( 
			&& dtype_get_charset_coll(cur_type->prtype) !=

				data_mysql_latin1_swedish_charset_coll)) {



		  	/* If character set is not latin1_swedish

			we have to devide character length by the

			maximum bytes needed for that character

			set. For example if we have unique prefix

			index for 1 utf8 character then we have

			actually 3 bytes allocated in the index.

			Therefore, we have to divide that with

			maximum bytes needed for utf8 character i.e.

			3 byges.*/



                        if ( dtuple_f_len > 0) {

			  charset = get_charset(

				dtype_get_charset_coll(cur_type->prtype), 

				MYF(MY_WME));



			  ut_ad(charset);

			  ut_ad(charset->mbmaxlen);



			  dtuple_f_len = dtuple_f_len / charset->mbmaxlen;



                          if ( dtuple_f_len == 0)

			    dtuple_f_len = 1;



			  rec_f_len = dtuple_f_len;

			} 



			ret = cmp_whole_field(cur_type,

				dfield_get_data(dtuple_field), dtuple_f_len,

				rec_b_ptr, rec_f_len);