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https://issues.apache.org/jira/browse/FLINK-10423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16647990#comment-16647990
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ASF GitHub Bot commented on FLINK-10423:
----------------------------------------
zentol commented on a change in pull request #6814:
[FLINK-10423][rocksdb][metrics] rocksdb native metrics monitor
URL: https://github.com/apache/flink/pull/6814#discussion_r224761096
##########
File path:
flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBNativeMetricMonitor.java
##########
@@ -0,0 +1,154 @@
+/*
+ * 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.flink.contrib.streaming.state;
+
+import org.apache.flink.annotation.Internal;
+import org.apache.flink.core.fs.CloseableRegistry;
+import org.apache.flink.metrics.Gauge;
+import org.apache.flink.metrics.MetricGroup;
+import org.apache.flink.metrics.View;
+import org.apache.flink.util.FlinkRuntimeException;
+import org.apache.flink.util.IOUtils;
+import org.apache.flink.util.ResourceGuard;
+
+import org.rocksdb.ColumnFamilyHandle;
+import org.rocksdb.RocksDB;
+import org.rocksdb.RocksDBException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.annotation.Nonnull;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+/**
+ * A monitor which pull {{@link RocksDB}} native metrics
+ * and forwards them to Flink's metric group. All metrics are
+ * unsigned longs and are reported at the column family level.
+ */
+@Internal
+public class RocksDBNativeMetricMonitor implements Closeable {
+
+ private final CloseableRegistry registeredGauges;
+
+ private final RocksDB db;
+
+ private final ResourceGuard.Lease lease;
+
+ private final RocksDBNativeMetricOptions options;
+
+ private final MetricGroup metricGroup;
+
+ RocksDBNativeMetricMonitor(
+ @Nonnull RocksDB db,
+ @Nonnull ResourceGuard guard,
+ @Nonnull RocksDBNativeMetricOptions options,
+ @Nonnull MetricGroup metricGroup
+ ) throws IOException {
+ this.db = db;
+ this.lease = guard.acquireResource();
+ this.options = options;
+ this.metricGroup = metricGroup;
+
+ this.registeredGauges = new CloseableRegistry();
+ }
+
+ /**
+ * Register gauges to pull native metrics for the column family.
+ * @param columnFamilyName group name for the new gauges
+ * @param handle native handle to the column family
+ */
+ void registerColumnFamily(String columnFamilyName, ColumnFamilyHandle
handle) {
+ try {
+ MetricGroup group =
metricGroup.addGroup(columnFamilyName);
+
+ for (String property : options.getProperties()) {
+ RocksDBNativeMetricView gauge = new
RocksDBNativeMetricView(
+ property,
+ handle,
+ db
+ );
+
+ group.gauge(property, gauge);
+ registeredGauges.registerCloseable(gauge);
+ }
+ } catch (IOException e) {
+ throw new FlinkRuntimeException("Unable to register
native metrics with RocksDB", e);
+ }
+ }
+
+ @Override
+ public void close() {
+ IOUtils.closeQuietly(registeredGauges);
+ IOUtils.closeQuietly(lease);
+ }
+
+ static class RocksDBNativeMetricView implements Gauge<String>, View,
Closeable {
+ private static final Logger LOG =
LoggerFactory.getLogger(RocksDBNativeMetricView.class);
+
+ private final String property;
+
+ private final ColumnFamilyHandle handle;
+
+ private final RocksDB db;
+
+ private volatile boolean open;
+
+ private long value;
+
+ private RocksDBNativeMetricView(
+ @Nonnull String property,
+ @Nonnull ColumnFamilyHandle handle,
+ @Nonnull RocksDB db
+ ) {
+ this.property = property;
+ this.handle = handle;
+ this.db = db;
+ this.open = true;
+ }
+
+ @Override
+ public String getValue() {
+ return Long.toUnsignedString(value);
+ }
+
+ @Override
+ public void update() {
+ if (open) {
Review comment:
There exists only a single thread per cluster that does the polling which is
also responsible for running reporters, so it can only be shutdown when the
cluster as a whole terminates. If the `MetricRegistry` is shutdown it is
guaranteed that no polling happens anymore.
A nicer way to do this would be to unregister the metrics (by closing the
group they were registered on) and enhance the
[ViewUpdaterTask](https://github.com/apache/flink/blob/master/flink-runtime/src/main/java/org/apache/flink/runtime/metrics/ViewUpdater.java)
to immediately react to unregistered metrics.
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> Forward RocksDB native metrics to Flink metrics reporter
> ---------------------------------------------------------
>
> Key: FLINK-10423
> URL: https://issues.apache.org/jira/browse/FLINK-10423
> Project: Flink
> Issue Type: New Feature
> Components: Metrics, State Backends, Checkpointing
> Reporter: Seth Wiesman
> Assignee: Seth Wiesman
> Priority: Major
> Labels: pull-request-available
>
> RocksDB contains a number of metrics at the column family level about current
> memory usage, open memtables, etc that would be useful to users wishing
> greater insight what rocksdb is doing. This work is inspired heavily by the
> comments on this rocksdb issue thread
> (https://github.com/facebook/rocksdb/issues/3216#issuecomment-348779233)
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