org.apache.hadoop.hive.metastore.RetryingRawStore.java Source code

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Here is the source code for org.apache.hadoop.hive.metastore.RetryingRawStore.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hive.metastore;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.lang.reflect.UndeclaredThrowableException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.common.JavaUtils;
import org.apache.hadoop.hive.common.classification.InterfaceAudience;
import org.apache.hadoop.hive.common.classification.InterfaceStability;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.metastore.api.MetaException;
import org.apache.hadoop.hive.metastore.hooks.JDOConnectionURLHook;
import org.apache.hadoop.util.ReflectionUtils;

@InterfaceAudience.Private
@InterfaceStability.Evolving
public class RetryingRawStore implements InvocationHandler {

    private static final Log LOG = LogFactory.getLog(RetryingRawStore.class);

    private final RawStore base;
    private int retryInterval = 0;
    private int retryLimit = 0;
    private MetaStoreInit.MetaStoreInitData metaStoreInitData = new MetaStoreInit.MetaStoreInitData();
    private final int id;
    private final HiveConf hiveConf;
    private final Configuration conf; // thread local conf from HMS

    protected RetryingRawStore(HiveConf hiveConf, Configuration conf, Class<? extends RawStore> rawStoreClass,
            int id) throws MetaException {
        this.conf = conf;
        this.hiveConf = hiveConf;
        this.id = id;

        // This has to be called before initializing the instance of RawStore
        init();

        this.base = (RawStore) ReflectionUtils.newInstance(rawStoreClass, conf);
    }

    public static RawStore getProxy(HiveConf hiveConf, Configuration conf, String rawStoreClassName, int id)
            throws MetaException {

        Class<? extends RawStore> baseClass = (Class<? extends RawStore>) MetaStoreUtils
                .getClass(rawStoreClassName);

        RetryingRawStore handler = new RetryingRawStore(hiveConf, conf, baseClass, id);

        return (RawStore) Proxy.newProxyInstance(RetryingRawStore.class.getClassLoader(), baseClass.getInterfaces(),
                handler);
    }

    private void init() throws MetaException {
        retryInterval = HiveConf.getIntVar(hiveConf, HiveConf.ConfVars.METASTOREINTERVAL);
        retryLimit = HiveConf.getIntVar(hiveConf, HiveConf.ConfVars.METASTOREATTEMPTS);
        // Using the hook on startup ensures that the hook always has priority
        // over settings in *.xml.  The thread local conf needs to be used because at this point
        // it has already been initialized using hiveConf.
        MetaStoreInit.updateConnectionURL(hiveConf, getConf(), null, metaStoreInitData);
    }

    private void initMS() {
        base.setConf(getConf());
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object ret = null;

        boolean gotNewConnectUrl = false;
        boolean reloadConf = HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.METASTOREFORCERELOADCONF);

        if (reloadConf) {
            MetaStoreInit.updateConnectionURL(hiveConf, getConf(), null, metaStoreInitData);
        }

        int retryCount = 0;
        Exception caughtException = null;
        while (true) {
            try {
                if (reloadConf || gotNewConnectUrl) {
                    initMS();
                }
                ret = method.invoke(base, args);
                break;
            } catch (javax.jdo.JDOException e) {
                caughtException = e;
            } catch (UndeclaredThrowableException e) {
                throw e.getCause();
            } catch (InvocationTargetException e) {
                if (e.getCause() instanceof javax.jdo.JDOException) {
                    // Due to reflection, the jdo exception is wrapped in
                    // invocationTargetException
                    caughtException = (javax.jdo.JDOException) e.getCause();
                } else
                    throw e.getCause();
            }

            if (retryCount >= retryLimit) {
                throw caughtException;
            }

            assert (retryInterval >= 0);
            retryCount++;
            LOG.error(String.format(
                    "JDO datastore error. Retrying metastore command " + "after %d ms (attempt %d of %d)",
                    retryInterval, retryCount, retryLimit));
            Thread.sleep(retryInterval);
            // If we have a connection error, the JDO connection URL hook might
            // provide us with a new URL to access the datastore.
            String lastUrl = MetaStoreInit.getConnectionURL(getConf());
            gotNewConnectUrl = MetaStoreInit.updateConnectionURL(hiveConf, getConf(), lastUrl, metaStoreInitData);
        }
        return ret;
    }

    private String addPrefix(String s) {
        return id + ": " + s;
    }

    public Configuration getConf() {
        return conf;
    }

}