[GitHub] BinShi-SecularBird commented on a change in pull request #425: PHOENIX-5069 Use asynchronous refresh to provide non-blocking Phoenix Stats Client Cache

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BinShi-SecularBird commented on a change in pull request #425: PHOENIX-5069 Use asynchronous refresh to provide non-blocking Phoenix Stats Client Cache
URL: https://github.com/apache/phoenix/pull/425#discussion_r248016990
 
 

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 File path: phoenix-core/src/test/java/org/apache/phoenix/query/PhoenixStatsCacheLoaderTest.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.phoenix.query;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.LoadingCache;
+import com.google.common.cache.Weigher;
+import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
+import org.apache.phoenix.schema.stats.GuidePostsInfo;
+import org.apache.phoenix.schema.stats.GuidePostsKey;
+import org.apache.phoenix.util.ByteUtil;
+import org.junit.Test;
+
+import java.lang.Thread;
+import java.util.Collections;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.ExecutorService;
+
+/**
+ * Test class around the PhoenixStatsCacheLoader.
+ */
+public class PhoenixStatsCacheLoaderTest {
+    /**
+     * {@link PhoenixStatsLoader} test implementation for the Stats Loader.
+     */
+    protected class TestStatsLoaderImpl implements PhoenixStatsLoader {
+        private int maxLength = 1;
+
+        @Override
+        public boolean needsLoad() {
+            // Whenever it's called, we try to load stats from stats table
+            // no matter it has been updated or not.
+            return true;
+        }
+
+        @Override
+        public GuidePostsInfo loadStats(GuidePostsKey statsKey, GuidePostsInfo prevGuidepostInfo) throws Exception {
+            try {
+                Thread.sleep(2000);
+            }
+            catch (InterruptedException e) {
+                assertFalse(true);
+            }
+
+            return new GuidePostsInfo(Collections.<Long> emptyList(),
+                    new ImmutableBytesWritable(ByteUtil.EMPTY_BYTE_ARRAY),
+                    Collections.<Long> emptyList(), maxLength++, 0, Collections.<Long> emptyList());
+        }
+    }
+
+    GuidePostsInfo getStats(LoadingCache<GuidePostsKey, GuidePostsInfo> cache, GuidePostsKey guidePostsKey) {
+        GuidePostsInfo guidePostsInfo;
+        try {
+            guidePostsInfo = cache.get(guidePostsKey);
+        } catch (ExecutionException e) {
+            assertFalse(true);
+            return GuidePostsInfo.NO_GUIDEPOST;
+        }
+
+        return guidePostsInfo;
+    }
+
+    void sleep(int x) {
+        try {
+            Thread.sleep(x);
+        }
+        catch (InterruptedException e) {
+            assertFalse(true);
+        }
+    }
+
+    @Test
+    public void testStatsBeingAutomaticallyRefreshed() {
+        ExecutorService executor = Executors.newFixedThreadPool(4);
+
+        LoadingCache<GuidePostsKey, GuidePostsInfo> cache = CacheBuilder.newBuilder()
+                // Refresh entries a given amount of time after they were written
+                .refreshAfterWrite(1000, TimeUnit.MILLISECONDS)
+                // Maximum total weight (size in bytes) of stats entries
+                .maximumWeight(QueryServicesOptions.DEFAULT_STATS_MAX_CACHE_SIZE)
+                // Defer actual size to the PTableStats.getEstimatedSize()
+                .weigher(new Weigher<GuidePostsKey, GuidePostsInfo>() {
+                    @Override public int weigh(GuidePostsKey key, GuidePostsInfo info) {
+                        return info.getEstimatedSize();
+                    }
+                })
+                // Log removals at TRACE for debugging
+                .removalListener(new GuidePostsCache.PhoenixStatsCacheRemovalListener())
+                // Automatically load the cache when entries are missing
+                .build(new PhoenixStatsCacheLoader(new TestStatsLoaderImpl(), executor));
+
+        GuidePostsKey guidePostsKey = new GuidePostsKey(new byte[4], new byte[4]);
+        GuidePostsInfo guidePostsInfo = getStats(cache, guidePostsKey);
+        assertTrue(guidePostsInfo.getMaxLength() == 1);
+        sleep(3000);
+        guidePostsInfo = getStats(cache, guidePostsKey);
 
 Review comment:
   Fixed by using CountDownLatch to guarantee deterministic test behavior.

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