netudima commented on code in PR #3606: URL: https://github.com/apache/cassandra/pull/3606#discussion_r1924074937
########## src/java/org/apache/cassandra/io/util/ThreadLocalReadAheadBuffer.java: ########## @@ -0,0 +1,152 @@ +/* + * 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.cassandra.io.util; + +import java.nio.ByteBuffer; +import java.util.Map; +import java.util.concurrent.ConcurrentHashMap; + +import io.netty.util.concurrent.FastThreadLocal; +import org.apache.cassandra.io.compress.BufferType; +import org.apache.cassandra.io.compress.CorruptBlockException; +import org.apache.cassandra.io.sstable.CorruptSSTableException; + +public final class ThreadLocalReadAheadBuffer +{ + + private final ChannelProxy channel; + + private final BufferType bufferType; + + private static final Map<String, FastThreadLocal<ByteBuffer>> blockBufferHolders = new ConcurrentHashMap<>(); + + private static final Map<String, FastThreadLocal<Integer>> currentBlocks = new ConcurrentHashMap<>(); + + private final FastThreadLocal<ByteBuffer> blockBufferHolder; + + private final FastThreadLocal<Integer> currentBlock; + + private final int bufferSize; + + public ThreadLocalReadAheadBuffer(ChannelProxy channel, int bufferSize, BufferType bufferType) + { + this.channel = channel; + this.bufferSize = bufferSize; + this.bufferType = bufferType; + blockBufferHolders.putIfAbsent(channel.filePath(), new FastThreadLocal<>() Review Comment: I afraid we have a kind of leak here: for every constructor call we create a new instance of FastThreadLocal. FastThreadLocal allocates an index (to store itself in a thread-local array): io.netty.util.concurrent.FastThreadLocal#index Eventually we will consume all values for this int and get IllegalStateException("too many thread-local indexed variables") from io.netty.util.internal.InternalThreadLocalMap#nextVariableIndex Dynamic allocation of FastThreadLocal instances is a dangerous thing, probably we should reconsider the logic in a way to use only a static number of FastThreadLocal instances.. Can we change the order and instead of Map<FilePath, ThreadLocal<Buffer>> have ThreadLocal<Map<FilePath, Buffer>>?.. -- 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: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org
