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Merge bk-internal.mysql.com:/home/bk/mysql-5.0

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into mysql.com:/opt/local/work/mysql-5.0-7306-new
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konstantin@mysql.com
2005-05-30 20:56:11 +04:00
parent 329d974df7 2d6a70c42a
commit e315f903d0
17 changed files with 69 additions and 104 deletions
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11
sql/opt_range.cc
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@ -7980,8 +7980,17 @@ void QUICK_GROUP_MIN_MAX_SELECT::update_key_stat()
}
}
}
else if (have_min && min_max_arg_part && min_max_arg_part->field->is_null())
else if (have_min && min_max_arg_part &&
min_max_arg_part->field->real_maybe_null())
{
/*
If a MIN/MAX argument value is NULL, we can quickly determine
that we're in the beginning of the next group, because NULLs
are always < any other value. This allows us to quickly
determine the end of the current group and jump to the next
group (see next_min()) and thus effectively increases the
usable key length.
*/
max_used_key_length+= min_max_arg_len;
++used_key_parts;
}