Commit 0b8c68ce authored by unknown's avatar unknown
Browse files

ha_innodb.cc: 

  Raise maximum column prefix len to 767 bytes, so that MySQL can create a column prefix index of 255 UTF-8 characters (each takes 3 bytes at the maximum); add comments about why innobase_get_at_most_n_mbchars() works ok
dict0mem.h:
  Raise maximum column prefix len to 767 bytes, so that MySQL can create a column prefix index of 255 UTF-8 characters (each takes 3 bytes at the maximum)
row0mysql.c:
  If MySQL tries to create a column prefix index longer that 255 UTF-8 characters, give an error, and drop the table from the InnoDB internal data dictionary. MySQL did not drop the table there in its own error handling.


innobase/row/row0mysql.c:
  If MySQL tries to create a column prefix index longer that 255 UTF-8 characters, give an error, and drop the table from the InnoDB internal data dictionary. MySQL did not drop the table there in its own error handling.
innobase/include/dict0mem.h:
  Raise maximum column prefix len to 767 bytes, so that MySQL can create a column prefix index of 255 UTF-8 characters (each takes 3 bytes at the maximum)
sql/ha_innodb.cc:
  Raise maximum column prefix len to 767 bytes, so that MySQL can create a column prefix index of 255 UTF-8 characters (each takes 3 bytes at the maximum); add comments about why innobase_get_at_most_n_mbchars() works ok
parent fdbc804c

innobase/include/dict0mem.h

+13 −4
Original line number Diff line number Diff line
@@ -151,7 +151,12 @@ struct dict_col_struct{ 
				in some of the functions below */

};



#define DICT_MAX_COL_PREFIX_LEN	512

/* DICT_MAX_COL_PREFIX_LEN is measured in bytes. Starting from 4.1.6, we

define max col prefix len as 3 * 256, so that one can create a column prefix

index on 256 characters of a TEXT field also in the UTF-8 charset. In that

charset, a character may take at most 3 bytes. */



#define DICT_MAX_COL_PREFIX_LEN	768



/* Data structure for a field in an index */

struct dict_field_struct{
@@ -160,9 +165,13 @@ struct dict_field_struct{ 
	ulint		order;		/* flags for ordering this field:

					DICT_DESCEND, ... */

	ulint		prefix_len;	/* 0 or the length of the column

					prefix in a MySQL index of type, e.g.,

					INDEX (textcol(25)); must be smaller

					than DICT_MAX_COL_PREFIX_LEN */

					prefix in bytes in a MySQL index of

					type, e.g., INDEX (textcol(25));

					must be smaller than

					DICT_MAX_COL_PREFIX_LEN; NOTE that

					in the UTF-8 charset, MySQL reserves

					sets this to 3 * the prefix len in

					UTF-8 chars */

};



/* Data structure for an index tree */

innobase/row/row0mysql.c

+11 −2
Original line number Diff line number Diff line
@@ -1630,6 +1630,8 @@ row_create_index_for_mysql( 
	

	trx->op_info = "creating index";



	trx_start_if_not_started(trx);



	/* Check that the same column does not appear twice in the index.

	Starting from 4.0.14, InnoDB should be able to cope with that, but

	safer not to allow them. */
@@ -1656,9 +1658,16 @@ row_create_index_for_mysql( 
				goto error_handling;

			}

		}

	}

		

	trx_start_if_not_started(trx);

		/* Check also that prefix_len < DICT_MAX_COL_PREFIX_LEN */



		if (dict_index_get_nth_field(index, i)->prefix_len

						>= DICT_MAX_COL_PREFIX_LEN) {

			err = DB_TOO_BIG_RECORD;



			goto error_handling;

		}

	}



	if (row_mysql_is_recovered_tmp_table(index->table_name)) {

sql/ha_innodb.cc

+17 −28
Original line number Diff line number Diff line
@@ -3525,10 +3525,6 @@ create_index( 
		        prefix_len = 0;

		}



		if (prefix_len >= DICT_MAX_COL_PREFIX_LEN) {

			DBUG_RETURN(-1);

		}



		/* We assume all fields should be sorted in ascending

		order, hence the '0': */
@@ -5333,39 +5329,32 @@ innobase_get_at_most_n_mbchars( 
	/* If the charset is multi-byte, then we must find the length of the

	first at most n chars in the string. If the string contains less

	characters than n, then we return the length to the end of the last

	full character. */

	character. */



	if (charset->mbmaxlen > 1) {

/*		ulint	right_value; */



		/* my_charpos() returns the byte length of the first n_chars

		characters, or the end of the last full character */

		characters, or a value bigger than the length of str, if

		there were not enough full characters in str.



		char_length = my_charpos(charset, str,

						str + data_len, n_chars);

		Why does the code below work:

		Suppose that we are looking for n UTF-8 characters.



		/*################################################*/

		/* TODO: my_charpos sometimes returns a non-sensical value

		that is BIGGER than data_len: try to fix this bug partly with

		these heuristics. This is NOT a complete bug fix! */

		1) If the string is long enough, then the prefix contains at

		least n complete UTF-8 characters + maybe some extra

		characters + an incomplete UTF-8 character. No problem in

		this case. The function returns the pointer to the

		end of the nth character.



		2) If the string is not long enough, then the string contains

		the complete value of a column, that is, only complete UTF-8

		characters, and we can store in the column prefix index the

		whole string. */



		char_length = my_charpos(charset, str,

						str + data_len, n_chars);

		if (char_length > data_len) {

			char_length = data_len;

		}		

		/*################################################*/



/*		printf("data_len %lu, n_chars %lu, char_len %lu\n",

				data_len, n_chars, char_length);

		if (data_len < n_chars) {

			right_value = data_len;

		} else {

			right_value = n_chars;

		}



		if (right_value != char_length) {

			printf("ERRRRRROOORRRRRRRRRRRR!!!!!!!!!\n");

		}

*/

	} else {

		if (data_len < prefix_len) {

			char_length = data_len;