Hi Serg! Please review the patch for Unique Index For Long (MDEV-371) (It is in bb-10.4-blob-index branch) Architecture:- We will create a virtual column DB_ROW_HASH_X (X is any number which makes this field name unique) for each long unique column which will store hash. At the time of ha_write_row we will check for hash collusions if we find same hash then we will retrieve the blob and then compare byte by byte. key_info for long unique have one extra key_part which will point to hash field. For example unique(a,b) key will have 3 key_parts :- a ,b DB_ROW_HASH_X But on server layer we can just see a,b parts on storage layer we can just see DB_ROW_HASH_X key_part. I have created 2 function setup_table_hash and resetup_table which helps in this transition. If user specify length of blob then we use LEFT function to trim the value. -- Regards Sachin Setiya Software Engineer at MariaDB