ArvinDevel commented on a change in pull request #832: Issue 620: Close the fileChannels for read when they are idle URL: https://github.com/apache/bookkeeper/pull/832#discussion_r167131090
########## File path: bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/EntryLogger.java ########## @@ -330,54 +333,216 @@ private int readFromLogChannel(long entryLogId, BufferedReadChannel channel, Byt * A thread-local variable that wraps a mapping of log ids to bufferedchannels * These channels should be used only for reading. logChannel is the one * that is used for writes. + * We use this Guava cache to store the BufferedReadChannel. + * When the BufferedReadChannel is removed, the underlying fileChannel's refCnt decrease 1, + * temporally use 1h to relax replace after reading. */ - private final ThreadLocal<Map<Long, BufferedReadChannel>> logid2Channel = - new ThreadLocal<Map<Long, BufferedReadChannel>>() { + private final ThreadLocal<Cache<Long, BufferedReadChannel>> logid2Channel = + new ThreadLocal<Cache<Long, BufferedReadChannel>>() { @Override - public Map<Long, BufferedReadChannel> initialValue() { + public Cache<Long, BufferedReadChannel> initialValue() { // Since this is thread local there only one modifier // We dont really need the concurrency, but we need to use // the weak values. Therefore using the concurrency level of 1 - return new MapMaker().concurrencyLevel(1) - .weakValues() - .makeMap(); + return CacheBuilder.newBuilder().concurrencyLevel(1) + .expireAfterAccess(readChannelCacheExpireTimeMs, TimeUnit.MILLISECONDS) + //decrease the refCnt + .removalListener(removal -> logid2FileChannel.get((Long) removal.getKey()).release()) + .build(readChannelLoader); + } + }; + + @VisibleForTesting + long getReadChannelCacheExpireTimeMs() { + return readChannelCacheExpireTimeMs; + } + + @VisibleForTesting + CacheLoader<Long, BufferedReadChannel> getReadChannelLoader() { + return readChannelLoader; + } + + private final CacheLoader<Long, BufferedReadChannel> readChannelLoader = + new CacheLoader<Long, BufferedReadChannel> () { + public BufferedReadChannel load(Long entryLogId) throws Exception { + + return getChannelForLogId(entryLogId); + } }; /** - * Each thread local buffered read channel can share the same file handle because reads are not relative - * and don't cause a change in the channel's position. We use this map to store the file channels. Each - * file channel is mapped to a log id which represents an open log file. + * FileChannelBackingCache used to cache RefCntFileChannels for read. + * In order to avoid get released file, adopt design of FileInfoBackingCache. + * @see FileInfoBackingCache */ - private final ConcurrentMap<Long, FileChannel> logid2FileChannel = new ConcurrentHashMap<Long, FileChannel>(); + class FileChannelBackingCache { + static final int DEAD_REF = -0xdead; + + final ConcurrentHashMap<Long, CachedFileChannel> fileChannels = new ConcurrentHashMap<>(); + + CachedFileChannel loadFileChannel(long logId) throws IOException { + CachedFileChannel cachedFileChannel = fileChannels.get(logId); + if (cachedFileChannel != null) { + boolean retained = cachedFileChannel.tryRetain(); Review comment: um, that's right. The ReadWriteLock is necessary, I'll refactor again. I thought that lock is used to guarantee FileInfo's file open/write operations before now. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services