Thoughts On UTF-8 Encoding In SQL Server 2019

Solomon Rutzky digs into UTF-8 support in SQL Server 2019 and has found a few bugs:

Let’s start with what we are told about this new feature. According to the documentation, the new UTF-8 Collations:

1. can be used …

   1. as a database-level default Collation
   2. as a column-level Collation
   3. by appending “_UTF8” to the end of any Supplementary Character-Aware Collation (i.e. either having “_SC” in their name, or being of level 140 or newer)
   4. with only the CHAR and VARCHAR

2. (implied) have no effect on NCHAR and NVARCHAR data (meaning: for these types, the UTF-8 Collations behave the same as their non-UTF-8 equivalents

3. “This feature may provide significant storage savings, depending on the character set in use.” (emphasis mine)

Solomon takes his normal, thorough approach to the problem and finds several issues.