System limits

This topic describes the rules and limits that apply when you use StarRocks.

• StarRocks uses the MySQL protocol for communication. You can connect to the StarRocks cluster via a MySQL client or JDBC. We recommend that you use a MySQL client whose version is 5.1 or later. Versions earlier than 5.1 do not support usernames that are longer than 16 characters.

• Naming conventions for clusters, databases, tables, views, columns, partitions, usernames, and roles:

  • The names can only consist of digits (0-9), letters (a-z or A-Z), and underscores (_).
  • The name cannot exceed 64 characters in length.
  • Except for column names, other names must start with a lowercase or uppercase letter.
  • Column names can start with an underscore (_).
  • Database, table, and view names are case-sensitive. Column names are not case-sensitive.

• Naming conventions for labels: You can specify the label of a job when you import data. The label name can consist of underscores (_), letters (a-z or A-Z), and digits (0-9), and cannot exceed 128 characters in length. The label name has no requirement for the starting character.

• When you create a table, the key column cannot be of the FLOAT or DOUBLE type. You can use the DECIMAL type to represent decimals.

• A VARCHAR value can be up to 65533 bytes (two bytes less than 65535 because the first two bytes are used to indicate the length).

• StarRocks supports only UTF8 encoding, not GBK.

• StarRocks does not support modifying column names in tables.

• By default, an expression can have a maximum of 10,000 children, which can be modified by using expr_child_limit in the fe.conf file.