MDEV-25985 Spider handle ">=" as ">" in some cases
The function spider_db_append_key_where_internal() converts HA_READ_AFTER_KEY to '>'. The conversion seems to be correct for single-column indexes because HA_READ_AFTER_KEY means "read the key after the provided value." However, how about multi-column indexes? Assume that there is a multi-column index on c1 and c2 and we search with the condition 'c1 >= 100 AND c2 > 200'. The key_range.flag corresponds to the search condition could be HA_READ_AFTER_KEY. In such a case, we could not simply convert HA_READ_AFTER_KEY to '>'. The correct conversion is to convert HA_READ_AFTER_KEY to '>' only for the last column in key_part_map and to convert HA_READ_AFTER_KEY to '>=' for the other column. The similar discussion also applies to the conversion from key_range.flag to a sign of inequality.
Showing
Please register or sign in to comment