jcamachor commented on a change in pull request #794: HIVE-21884
URL: https://github.com/apache/hive/pull/794#discussion_r335749992
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File path:
ql/src/java/org/apache/hadoop/hive/ql/schq/ScheduledQueryExecutionService.java
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@@ -0,0 +1,159 @@
+package org.apache.hadoop.hive.ql.schq;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.hadoop.hive.conf.HiveConf;
+import org.apache.hadoop.hive.metastore.api.QueryState;
+import org.apache.hadoop.hive.metastore.api.ScheduledQueryPollResponse;
+import org.apache.hadoop.hive.metastore.api.ScheduledQueryProgressInfo;
+import org.apache.hadoop.hive.ql.DriverFactory;
+import org.apache.hadoop.hive.ql.IDriver;
+import org.apache.hadoop.hive.ql.processors.CommandProcessorResponse;
+import org.apache.hadoop.hive.ql.session.SessionState;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.util.concurrent.ThreadFactoryBuilder;
+
+public class ScheduledQueryExecutionService implements Closeable {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(ScheduledQueryExecutionService.class);
+
+ private ScheduledQueryExecutionContext context;
+ private ScheduledQueryExecutor worker;
+
+ public static ScheduledQueryExecutionService
startScheduledQueryExecutorService(HiveConf conf) {
+ MetastoreBasedScheduledQueryService qService = new
MetastoreBasedScheduledQueryService(conf);
+ ExecutorService executor =
+ Executors.newCachedThreadPool(
+ new
ThreadFactoryBuilder().setDaemon(true).setNameFormat("Scheduled Query Thread
%d").build());
+ ScheduledQueryExecutionContext ctx = new
ScheduledQueryExecutionContext(executor, conf, qService);
+ return new ScheduledQueryExecutionService(ctx);
+ }
+
+ public ScheduledQueryExecutionService(ScheduledQueryExecutionContext ctx) {
+ context = ctx;
+ ctx.executor.submit(worker = new ScheduledQueryExecutor());
+ ctx.executor.submit(new ProgressReporter());
+ }
+
+ class ScheduledQueryExecutor implements Runnable {
+
+ private ScheduledQueryProgressInfo info;
+
+ @Override
+ public void run() {
+ while (true) {
+ ScheduledQueryPollResponse q =
context.schedulerService.scheduledQueryPoll();
+ if (q.isSetExecutionId()) {
+ try{
+ processQuery(q);
+ } catch (Throwable t) {
+ LOG.error("Unexpected exception during scheduled query
processing", t);
+ }
+ } else {
+ try {
+ Thread.sleep(context.getIdleSleepTime());
+ } catch (InterruptedException e) {
+ Thread.currentThread().interrupt();
+ LOG.info("interrupted");
+ break;
+ }
+ }
+ }
+ }
+
+ QueryState lastState;
+ public synchronized void reportQueryProgress() {
+ if (info != null) {
+ if(lastState == QueryState.FINISHED || lastState ==
QueryState.ERRORED) {
+ return;
+ }
+ LOG.info("Reporting query progress of {} as {} err:{}",
info.getScheduledExecutionId(), info.getState(),
+ info.getErrorMessage());
+ context.schedulerService.scheduledQueryProgress(info);
+ lastState=info.getState();
+ }
+ }
+
+ private void processQuery(ScheduledQueryPollResponse q) {
Review comment:
We need to fix 2. One of the common use cases that we were discussing for
scheduled queries was incrementally refreshing contents in a table in a
transactional way, e.g., pulling data from Kafka. Currently, if query can be
assumed dead and then come back to life, we may basically end up inserting data
more than once in target object. You could just grab an exclusive execution
lock on the scheduled query identifier to prevent this from happening, we
already have mechanisms to do that (fwiw we have similar logic for incremental
materialized view rebuild).
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