MasterDaemon.java

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//
//   http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.doris.common.util;

import org.apache.doris.catalog.Env;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

/*
 * MasterDaemon is a kind of thread that will wait Catalog to be ready before running.
 * And it can run in all types of FE.
 */
public class MasterDaemon extends Daemon {
    private static final Logger LOG = LogManager.getLogger(MasterDaemon.class);

    public MasterDaemon() {
    }

    public MasterDaemon(String name) {
        super(name);
    }

    public MasterDaemon(String name, long intervalMs) {
        super(name, intervalMs);
    }

    @Override
    protected final void runOneCycle() {
        while (!Env.getServingEnv().isReady()) {
            // here we use getServingEnv(), not getCurrentEnv() because we truly want the Catalog instance,
            // not the Checkpoint catalog instance.
            // and if catalog is not ready, do not run
            try {
                // not return, but sleep a while. to avoid some thread with large running interval will
                // wait for a long time to start again.
                Thread.sleep(100);
            } catch (InterruptedException e) {
                LOG.warn("interrupted exception. thread: {}", getName(), e);
            }
        }

        runAfterCatalogReady();
    }

    // override by derived classes
    protected void runAfterCatalogReady() {

    }
}