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https://issues.apache.org/jira/browse/FLINK-10423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16653320#comment-16653320
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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_r225865415
##########
File path:
flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBNativeMetricMonitor.java
##########
@@ -0,0 +1,170 @@
+/*
+ * 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.metrics.Gauge;
+import org.apache.flink.metrics.MetricGroup;
+import org.apache.flink.metrics.View;
+
+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 javax.annotation.concurrent.GuardedBy;
+
+import java.io.Closeable;
+import java.math.BigInteger;
+
+/**
+ * A monitor which pulls {{@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 static final Logger LOG =
LoggerFactory.getLogger(RocksDBNativeMetricMonitor.class);
+
+ private final RocksDBNativeMetricOptions options;
+
+ private final MetricGroup metricGroup;
+
+ private final Object lock;
+
+ @GuardedBy("lock")
+ private RocksDB rocksDB;
+
+ RocksDBNativeMetricMonitor(
+ @Nonnull RocksDB rocksDB,
+ @Nonnull RocksDBNativeMetricOptions options,
+ @Nonnull MetricGroup metricGroup
+ ) {
+ this.options = options;
+ this.metricGroup = metricGroup;
+ this.rocksDB = rocksDB;
+
+ this.lock = new Object();
+ }
+
+ /**
+ * 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) {
+ MetricGroup group = metricGroup.addGroup(columnFamilyName);
+
+ for (String property : options.getProperties()) {
+ RocksDBNativeMetricView gauge = new
RocksDBNativeMetricView(handle, property);
+ group.gauge(property, gauge);
+ }
+ }
+
+ /**
+ * Updates the value of metricView if the reference is still valid.
+ */
+ private void setProperty(ColumnFamilyHandle handle, String property,
RocksDBNativeMetricView metricView) {
+ if (metricView.isClosed()) {
Review comment:
ah. hmm...
Let's say that an exception occurs when retrieving the value from RocksDB.
How likely is it that this exception happens again? I.e. how reliable are
failure-cases? Currently, if there is any intermittent failure the metric is
disabled forever.
If this is more of an all-or-nothing kind of thing we could try it out once
before registering the metric and skipping the registration if it fails, and
only skip repeated logging in the metric.
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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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