[FLINK-17759][runtime] Remove unused RestartIndividualStrategy

flink-core/src/main/java/org/apache/flink/configuration/JobManagerOptions.java

@@ -232,11 +232,6 @@ public class JobManagerOptions {
 
  /**
  * This option specifies the failover strategy, i.e. how the job computation recovers from task failures.
- *
- * <p>The option "individual" is intentionally not included for its known limitations.
- * It only works when all tasks are not connected, in which case the "region"
- * failover strategy would also restart failed tasks individually.
- * The new "region" strategy supersedes "individual" strategy and should always work.
  */
  @Documentation.Section({Documentation.Sections.ALL_JOB_MANAGER, Documentation.Sections.EXPERT_FAULT_TOLERANCE})
  @Documentation.OverrideDefault("region")

flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/failover/FailoverStrategyLoader.java

@@ -35,9 +35,6 @@ public class FailoverStrategyLoader {
  /** Config name for the {@link RestartAllStrategy}. */
  public static final String FULL_RESTART_STRATEGY_NAME = "full";
 
- /** Config name for the {@link RestartIndividualStrategy}. */
- public static final String INDIVIDUAL_RESTART_STRATEGY_NAME = "individual";
-
  // ------------------------------------------------------------------------
 
  /**
@@ -59,9 +56,6 @@ public static FailoverStrategy.Factory loadFailoverStrategy(Configuration config
  case FULL_RESTART_STRATEGY_NAME:
  return new RestartAllStrategy.Factory();
 
- case INDIVIDUAL_RESTART_STRATEGY_NAME:
- return new RestartIndividualStrategy.Factory();
-
  default:
  // we could interpret the parameter as a factory class name and instantiate that
  // for now we simply do not support this