Class HistoryLevelSetupCommand

  • All Implemented Interfaces:

    public final class HistoryLevelSetupCommand
    extends java.lang.Object
    implements Command<java.lang.Void>
    • Constructor Detail

      • HistoryLevelSetupCommand

        public HistoryLevelSetupCommand()
    • Method Detail

      • dbCreateHistoryLevel

        public static void dbCreateHistoryLevel​(CommandContext commandContext)
      • databaseHistoryLevel

        public static java.lang.Integer databaseHistoryLevel​(CommandContext commandContext)
        Integer value representing the history level or null if none found
      • checkStartupLockExists

        protected void checkStartupLockExists​(CommandContext commandContext)
      • acquireExclusiveLock

        protected void acquireExclusiveLock​(CommandContext commandContext)
      • isRetryable

        public boolean isRetryable()
        When CockroachDB is used, this command may be retried multiple times until it is successful, or the retries are exhausted. CockroachDB uses a stricter, SERIALIZABLE transaction isolation which ensures a serialized manner of transaction execution. A concurrent transaction that attempts to modify the same data as another transaction is required to abort, rollback and retry. This also makes our use-case of pessimistic locks redundant since we only use them as synchronization barriers, and not to lock actual data which would protect it from concurrent modifications. The HistoryLevelSetup command only executes internal code, so we are certain that a retry of a failed command will not impact user data, and may be performed multiple times.
        Specified by:
        isRetryable in interface Command<java.lang.Void>
        true if the CrdbTransactionRetryInterceptor can make a transparent retry of this command upon failure with a CrdbTransactionRetryException (only used when running on CockroachDB).