abstractdog commented on code in PR #5174:
URL: https://github.com/apache/hive/pull/5174#discussion_r1551593916
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ql/src/java/org/apache/hadoop/hive/ql/exec/tez/HiveSplitGenerator.java:
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@@ -154,6 +165,92 @@ private void prepare(InputInitializerContext
initializerContext) throws IOExcept
LOG.info("SplitLocationProvider: " + splitLocationProvider);
}
+ /**
+ * SplitSerializer is a helper class for taking care of serializing splits
to the tez scratch dir
+ * when a size criteria defined by
"hive.tez.split.fs.serialization.threshold" is met.
+ * It utilizes an ExecutorService for parallel writes to prevent a single
split write operation
+ * becoming the bottleneck (as write() is called from a loop currently).
+ */
+ class SplitSerializer {
+ // fields needed for filepath
+ private String queryId;
+ private String inputName;
+ private int vertexId;
+ private Path appStagingPath;
+ // metrics
+ private AtomicInteger timeSpentWithSplitWriteMs;
+ private AtomicInteger splitsWritten;
+ // lazy initialized filesystem and executor
+ private FileSystem fs;
+ private ExecutorService executor;
+
+ /**
+ * Lazy init filesystem and executor service: don't initialize if there is
no split serialized at all.
+ * No need to synchronize, this is called from a loop.
+ */
+ private void lazyInit() throws IOException {
+ if (fs != null) {
+ return;
+ }
+ queryId = jobConf.get(HiveConf.ConfVars.HIVEQUERYID.varname);
+ inputName = getContext().getInputName();
+ vertexId = getContext().getVertexId();
+ appStagingPath = TezCommonUtils.getTezSystemStagingPath(conf,
getContext().getApplicationId().toString());
+
+ timeSpentWithSplitWriteMs = new AtomicInteger(0);
+ splitsWritten = new AtomicInteger(0);
+
+ fs = appStagingPath.getFileSystem(jobConf);
+ executor = Executors.newFixedThreadPool(8,
+ new ThreadFactoryBuilder().setDaemon(true)
Review Comment:
ack
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