I understand that if the length is > 255 it will require 2 bytes to store the length prefix. I just need to verify my assumptions. Please tell me the length prefix and the length of string('abcd') for charsets(latin1, ucs2, utf8mb4). For a varchar(20) column. The documentaton says:
[...] For the string 'abcd', L is 4 and the storage requirement is five bytes. If the same column is instead declared to use the ucs2 double-byte character set, the storage requirement is 10 bytes: The length of 'abcd' is eight bytes and the column requires two bytes to store lengths because the maximum length is greater than 255 (up to 510 bytes). [...]
Reference: 11.7 Data Type Storage Requirements (Oracle | Docs)
I just don't understand why for 'abcd' with charset 'ucs2' it requires 2 byte length prefix even after it being less than 255.