ob_max_read_stale_time

Overview

ob_max_read_stale_time specifies the maximum latency threshold (in microseconds) for weak-consistency read queries.

Privilege requirements

• Query variables

  • Global level

    The sys tenant and all user tenants can use the SHOW VARIABLES statement or the information_schema.GLOBAL_VARIABLES view (in MySQL-compatible mode) to view the values of global system variables.

  • Session level

    The sys tenant and all user tenants can use the SHOW VARIABLES statement or the information_schema.SESSION_VARIABLES view (in MySQL-compatible mode) to view the values of session system variables.

• Modify variables

  • Global effective

    • The sys tenant can directly modify the values of global system variables.

    • MySQL user tenants must have the SUPER or ALTER SYSTEM privilege to modify the values of global system variables.

  • Session expiration

    The sys tenant and all user tenants can directly modify the values of session system variables for their own tenants.

Attributes

Usage instructions

The session-level weak read latency threshold specifies that the data read by a weak-read request of the current session must be within the set latency threshold. Different sessions can be configured with different latency thresholds.

Configuration example

Set the maximum latency threshold for weak-consistency read queries to 5,000,000 μs.

• Session expiration

  obclient> SET ob_max_read_stale_time =5000000;
  

• Effective globally

  obclient> SET GLOBAL ob_max_read_stale_time =5000000;