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ha_innodb.cc:

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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.
This commit is contained in:
heikki@hundin.mysql.fi
2004-10-05 17:08:22 +03:00
parent 092d1a5084
commit 3985d58ad2
3 changed files with 41 additions and 34 deletions
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45
sql/ha_innodb.cc
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@@ -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.
Why does the code below work:
Suppose that we are looking for n UTF-8 characters.
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);
/*################################################*/
/* 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! */
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;