utf-8 vs latin1

UTF8 Advantages:

  1. Supports most languages, including RTL languages such as Hebrew.

  2. No translation needed when importing/exporting data to UTF8 aware components (JavaScript, Java, etc).

UTF8 Disadvantages:

  1. Non-ASCII characters will take more time to encode and decode, due to their more complex encoding scheme.

  2. Non-ASCII characters will take more space as they may be stored using more than 1 byte (characters not in the first 127 characters of the ASCII characters set). A CHAR(10) or VARCHAR(10) field may need up to 30 bytes to store some UTF8 characters.

  3. Collations other than utf8_bin will be slower as the sort order will not directly map to the character encoding order), and will require translation in some stored procedures (as variables default to utf8_general_ci collation).

  4. If you need to JOIN UTF8 and non-UTF8 fields, MySQL will impose a SEVERE performance hit. What would be sub-second queries could potentially take minutes if the fields joined are different character sets/collations.

Bottom line:

If you don't need to support non-Latin1 languages, want to achieve maximum performance, or already have tables using latin1, choose latin1.

Otherwise, choose UTF8.


latin1 has the advantage that it is a single-byte encoding, therefore it can store more characters in the same amount of storage space because the length of string data types in MySql is dependent on the encoding. The manual states that

To calculate the number of bytes used to store a particular CHAR, VARCHAR, or TEXT column value, you must take into account the character set used for that column and whether the value contains multibyte characters. In particular, when using a utf8 Unicode character set, you must keep in mind that not all characters use the same number of bytes. utf8mb3 and utf8mb4 character sets can require up to three and four bytes per character, respectively. For a breakdown of the storage used for different categories of utf8mb3 or utf8mb4 characters, see Section 10.9, “Unicode Support”.

Furthermore lots of string operations (such as taking substrings and collation-dependent compares) are faster with single-byte encodings.

In any case, latin1 is not a serious contender if you care about internationalization at all. It can be an appropriate choice when you will be storing known safe values (such as percent-encoded URLs).


@Ross Smith II, Point 4 is worth gold, meaning inconsistency between columns can be dangerous.

To add value to the already good answers, here is a small performance test about the difference between charsets:

A modern 2013 server, real use table with 20000 rows, no index on concerned column.

SELECT 4 FROM subscribers WHERE 1 ORDER BY time_utc_str; (4 is cache buster)

  • varchar(20) CHARACTER SET latin1 COLLATION latin1_bin: 15ms
  • varbinary(20): 17ms
  • utf8_bin: 20ms
  • utf8_general_ci: 23ms

For simple strings like numerical dates, my decision would be, when performance is concerned, using utf8_bin (CHARACTER SET utf8 COLLATE utf8_bin). This would prevent any adverse effects with other code that expects database charsets to be utf8 while still being sort of binary.

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Mysql

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