ben-manes commented on a change in pull request #3371: URL: https://github.com/apache/hbase/pull/3371#discussion_r649731027
########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SyncFutureCache.java ########## @@ -0,0 +1,80 @@ +/* + * 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.hadoop.hbase.regionserver.wal; + +import java.util.concurrent.TimeUnit; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hbase.HConstants; +import org.apache.yetus.audience.InterfaceAudience; +import org.apache.hbase.thirdparty.com.google.common.cache.Cache; +import org.apache.hbase.thirdparty.com.google.common.cache.CacheBuilder; + +/** + * A cache of {@link SyncFuture}s. This class supports two methods + * {@link SyncFutureCache#getIfPresentOrNew()} and {@link SyncFutureCache#offer()}. + * + * Usage pattern: + * SyncFuture sf = syncFutureCache.getIfPresentOrNew(); + * sf.reset(...); + * // Use the sync future + * finally: syncFutureCache.offer(sf); + * + * Offering the sync future back to the cache makes it eligible for reuse within the same thread + * context. Cache keyed by the accessing thread instance and automatically invalidated if it remains + * unused for {@link SyncFutureCache#SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS} minutes. + */ +@InterfaceAudience.Private +public final class SyncFutureCache { + + private final long SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS = 2; + + private final Cache<Thread, SyncFuture> syncFutureCache; + + public SyncFutureCache(final Configuration conf) { + final int handlerCount = conf.getInt(HConstants.REGION_SERVER_HANDLER_COUNT, + HConstants.DEFAULT_REGION_SERVER_HANDLER_COUNT); + syncFutureCache = CacheBuilder.newBuilder().initialCapacity(handlerCount) + .expireAfterWrite(SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS, TimeUnit.MINUTES).build(); + } + + public SyncFuture getIfPresentOrNew() { + final SyncFuture[] result = {null}; + // Invalidate the entry if a mapping exists. We do not want it to be reused at the same time. + syncFutureCache.asMap().compute(Thread.currentThread(), (thread, syncFuture) -> { + result[0] = syncFuture; + return null; + }); Review comment: you could simplify this by using `remove(key)` instead of a computation, e.g. ```java SyncFuture future = syncFutureCache.asMap().remove(Thread.currentThread()); return (future == null) ? new SyncFuture() : future; ``` ########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SyncFutureCache.java ########## @@ -0,0 +1,80 @@ +/* + * 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.hadoop.hbase.regionserver.wal; + +import java.util.concurrent.TimeUnit; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hbase.HConstants; +import org.apache.yetus.audience.InterfaceAudience; +import org.apache.hbase.thirdparty.com.google.common.cache.Cache; +import org.apache.hbase.thirdparty.com.google.common.cache.CacheBuilder; + +/** + * A cache of {@link SyncFuture}s. This class supports two methods + * {@link SyncFutureCache#getIfPresentOrNew()} and {@link SyncFutureCache#offer()}. + * + * Usage pattern: + * SyncFuture sf = syncFutureCache.getIfPresentOrNew(); + * sf.reset(...); + * // Use the sync future + * finally: syncFutureCache.offer(sf); + * + * Offering the sync future back to the cache makes it eligible for reuse within the same thread + * context. Cache keyed by the accessing thread instance and automatically invalidated if it remains + * unused for {@link SyncFutureCache#SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS} minutes. + */ +@InterfaceAudience.Private +public final class SyncFutureCache { + + private final long SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS = 2; + + private final Cache<Thread, SyncFuture> syncFutureCache; + + public SyncFutureCache(final Configuration conf) { + final int handlerCount = conf.getInt(HConstants.REGION_SERVER_HANDLER_COUNT, + HConstants.DEFAULT_REGION_SERVER_HANDLER_COUNT); + syncFutureCache = CacheBuilder.newBuilder().initialCapacity(handlerCount) + .expireAfterWrite(SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS, TimeUnit.MINUTES).build(); + } + + public SyncFuture getIfPresentOrNew() { + final SyncFuture[] result = {null}; + // Invalidate the entry if a mapping exists. We do not want it to be reused at the same time. + syncFutureCache.asMap().compute(Thread.currentThread(), (thread, syncFuture) -> { + result[0] = syncFuture; + return null; + }); + if (result[0] != null) { + return result[0]; + } + return new SyncFuture(); + } + + /** + * Offers the sync future back to the cache for reuse. + */ + public void offer(SyncFuture syncFuture) { + syncFutureCache.asMap().putIfAbsent(syncFuture.getThread(), syncFuture); + } + + public void cleanUp() { + if (syncFutureCache != null) { + syncFutureCache.invalidateAll(); + } + } Review comment: This might be a confusing method name, as `cleanUp` for the cache lib means that pending maintenance work is performed immediately (e.g. discarding any expired entries). It doesn't clear the cache like this does, so a user might be surprised by whichever mental model they have. Instead, please call this `clear`, `invalidateAll`, etc to avoid conflicting names. ########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SyncFutureCache.java ########## @@ -0,0 +1,80 @@ +/* + * 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.hadoop.hbase.regionserver.wal; + +import java.util.concurrent.TimeUnit; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hbase.HConstants; +import org.apache.yetus.audience.InterfaceAudience; +import org.apache.hbase.thirdparty.com.google.common.cache.Cache; +import org.apache.hbase.thirdparty.com.google.common.cache.CacheBuilder; + +/** + * A cache of {@link SyncFuture}s. This class supports two methods + * {@link SyncFutureCache#getIfPresentOrNew()} and {@link SyncFutureCache#offer()}. + * + * Usage pattern: + * SyncFuture sf = syncFutureCache.getIfPresentOrNew(); + * sf.reset(...); + * // Use the sync future + * finally: syncFutureCache.offer(sf); + * + * Offering the sync future back to the cache makes it eligible for reuse within the same thread + * context. Cache keyed by the accessing thread instance and automatically invalidated if it remains + * unused for {@link SyncFutureCache#SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS} minutes. + */ +@InterfaceAudience.Private +public final class SyncFutureCache { + + private final long SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS = 2; + + private final Cache<Thread, SyncFuture> syncFutureCache; + + public SyncFutureCache(final Configuration conf) { + final int handlerCount = conf.getInt(HConstants.REGION_SERVER_HANDLER_COUNT, + HConstants.DEFAULT_REGION_SERVER_HANDLER_COUNT); + syncFutureCache = CacheBuilder.newBuilder().initialCapacity(handlerCount) Review comment: I'm not sure if there is a benefit over a `ThreadLocal` in your case. The expiration time here seems to be only to evict when the thread dies, which a TL does automatically. A `weakKey` cache might be the closest equivalent to that. ########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/wal/SyncFutureCache.java ########## @@ -0,0 +1,80 @@ +/* + * 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.hadoop.hbase.regionserver.wal; + +import java.util.concurrent.TimeUnit; +import org.apache.hadoop.conf.Configuration; +import org.apache.hadoop.hbase.HConstants; +import org.apache.yetus.audience.InterfaceAudience; +import org.apache.hbase.thirdparty.com.google.common.cache.Cache; +import org.apache.hbase.thirdparty.com.google.common.cache.CacheBuilder; + +/** + * A cache of {@link SyncFuture}s. This class supports two methods + * {@link SyncFutureCache#getIfPresentOrNew()} and {@link SyncFutureCache#offer()}. + * + * Usage pattern: + * SyncFuture sf = syncFutureCache.getIfPresentOrNew(); + * sf.reset(...); + * // Use the sync future + * finally: syncFutureCache.offer(sf); + * + * Offering the sync future back to the cache makes it eligible for reuse within the same thread + * context. Cache keyed by the accessing thread instance and automatically invalidated if it remains + * unused for {@link SyncFutureCache#SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS} minutes. + */ +@InterfaceAudience.Private +public final class SyncFutureCache { + + private final long SYNC_FUTURE_INVALIDATION_TIMEOUT_MINS = 2; + + private final Cache<Thread, SyncFuture> syncFutureCache; + + public SyncFutureCache(final Configuration conf) { + final int handlerCount = conf.getInt(HConstants.REGION_SERVER_HANDLER_COUNT, + HConstants.DEFAULT_REGION_SERVER_HANDLER_COUNT); + syncFutureCache = CacheBuilder.newBuilder().initialCapacity(handlerCount) Review comment: It also looks like your on 2.8.1, whereas a putIfAbsent optimization was added in [2.8.2](https://github.com/ben-manes/caffeine/releases/tag/v2.8.2) to avoid locking if the entry is present. That might help. -- This is an automated message from the Apache Git Service. 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