Introduction to configuration management

seekdb manages configurations by setting configuration items and system variables.

Configuration items

Configuration items are primarily used for O&M and are commonly used to control the behavior of machines and higher-level systems. They can be used as startup parameters and can be modified at runtime to adjust system behavior.

System variables

System variables are typically bound to user sessions and are used to control SQL behavior at the session level.

Both global and session-level variables are supported. When a global system variable is set, it does not take effect in the current session. However, any new session will read the updated variable value. When a session-level system variable is set, it only takes effect in the current session.

Comparison between system configuration items and system variables

Feature	System Configuration Item	System Variable
Scope of effect	Instance	Global or session level
Effective method	Dynamic effective: when edit_level is dynamic_effective. Effective after restart: when edit_level is static_effective.	Session-level variables only take effect in the current session and are ineffective in other sessions. Global-level variables are ineffective in the current session and will only take effect after a new session is established upon re-login.
Modification method	Supports modification through SQL statements. Example: Alter SYSTEM SET schema_history_expire_time='1h'; Supports modification through startup parameters. Example: /usr/bin/observer --base-dir /var/lib/oceanbase-lite --schema_history_expire_time='1h'	Only supports modification through SQL statements. Example: SET ob_query_timeout = 20000000; SET GLOBAL ob_query_timeout = 20000000;
Lifecycle	Long, from process startup to exit.	Short, effective only after the schema is successfully created.
Query method	You can use the SHOW PARAMETERS statement to query. Example: SHOW PARAMETERS LIKE 'schema_history_expire_time';	You can use the SHOW [GLOBAL] VARIABLES or SELECT statement to query. Examples: SHOW VARIABLES LIKE 'ob_query_timeout'; SHOW GLOBAL VARIABLES LIKE 'ob_query_timeout'; SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME = 'ob_query_timeout'; SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES WHERE VARIABLE_NAME = 'ob_query_timeout';