uschindler commented on code in PR #11796: URL: https://github.com/apache/lucene/pull/11796#discussion_r982891128
########## lucene/misc/src/java/org/apache/lucene/misc/store/ByteWritesTrackingDirectoryWrapper.java: ########## @@ -0,0 +1,118 @@ +/* + * 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.lucene.misc.store; + +import java.io.IOException; +import java.util.concurrent.atomic.AtomicLong; +import org.apache.lucene.store.Directory; +import org.apache.lucene.store.FilterDirectory; +import org.apache.lucene.store.IOContext; +import org.apache.lucene.store.IndexOutput; + +/** {@link FilterDirectory} that tracks write amplification factor */ +public final class ByteWritesTrackingDirectoryWrapper extends FilterDirectory { + + private final AtomicLong flushedBytes = new AtomicLong(); + private final AtomicLong mergedBytes = new AtomicLong(); + private final AtomicLong realTimeFlushedBytes = new AtomicLong(); Review Comment: Volatile is worse than AtomicLong, because it has a barrier on both read and write. So the atomic update is better. ########## lucene/misc/src/java/org/apache/lucene/misc/store/ByteWritesTrackingDirectoryWrapper.java: ########## @@ -0,0 +1,118 @@ +/* + * 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.lucene.misc.store; + +import java.io.IOException; +import java.util.concurrent.atomic.AtomicLong; +import org.apache.lucene.store.Directory; +import org.apache.lucene.store.FilterDirectory; +import org.apache.lucene.store.IOContext; +import org.apache.lucene.store.IndexOutput; + +/** {@link FilterDirectory} that tracks write amplification factor */ +public final class ByteWritesTrackingDirectoryWrapper extends FilterDirectory { + + private final AtomicLong flushedBytes = new AtomicLong(); + private final AtomicLong mergedBytes = new AtomicLong(); + private final AtomicLong realTimeFlushedBytes = new AtomicLong(); Review Comment: Do we really read from another thread while writing? Updating the counter is fine as it only happens in one thread. The problem is reading so we get a value that's up-to-date. The question is how up-to-date it needs to be. Maybe we can have a standard long value that gets updated by the writing thread. Every n~1000 bytes written we update the atomic one. What do you think? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
