sijie 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_r171943988
##########
File path:
bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/EntryLogger.java
##########
@@ -326,59 +353,45 @@ private int readFromLogChannel(long entryLogId,
BufferedReadChannel channel, Byt
return channel.read(buff, pos);
}
+ final ConcurrentLinkedQueue<Cache<Long, EntryLogBufferedReadChannel>>
readChannelCaches =
+ new ConcurrentLinkedQueue<>();
+
/**
* 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>>() {
+ final ThreadLocal<Cache<Long, EntryLogBufferedReadChannel>>
logid2ReadChannel =
+ new ThreadLocal<Cache<Long, EntryLogBufferedReadChannel>>() {
@Override
- public Map<Long, BufferedReadChannel> initialValue() {
+ public Cache<Long, EntryLogBufferedReadChannel> 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();
+ Cache<Long, EntryLogBufferedReadChannel> cache =
+ CacheBuilder.newBuilder().concurrencyLevel(1)
+ .expireAfterAccess(readChannelCacheExpireTimeMs,
TimeUnit.MILLISECONDS)
+ //decrease the refCnt
+ .removalListener(( RemovalListener<Long,
EntryLogBufferedReadChannel>) removal
+ ->
removal.getValue().release()).ticker(getTicker()).build();
+ readChannelCaches.add(cache);
+ return cache;
}
};
- /**
- * 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.
- */
- private final ConcurrentMap<Long, FileChannel> logid2FileChannel = new
ConcurrentHashMap<Long, FileChannel>();
-
- /**
- * Put the logId, bc pair in the map responsible for the current thread.
- * @param logId
- * @param bc
- */
- public BufferedReadChannel putInReadChannels(long logId,
BufferedReadChannel bc) {
- Map<Long, BufferedReadChannel> threadMap = logid2Channel.get();
- return threadMap.put(logId, bc);
+ Ticker getTicker() {
+ return Ticker.systemTicker();
}
/**
- * Remove all entries for this log file in each thread's cache.
- * @param logId
+ * 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.
+ * Each file channel is mapped to a log id which represents an open log
file.
*/
- public void removeFromChannelsAndClose(long logId) {
- FileChannel fileChannel = logid2FileChannel.remove(logId);
- if (null != fileChannel) {
- try {
- fileChannel.close();
- } catch (IOException e) {
- LOG.warn("Exception while closing channel for log file:" +
logId);
- }
- }
- }
-
- public BufferedReadChannel getFromChannels(long logId) {
- return logid2Channel.get().get(logId);
- }
+ FileChannelBackingCache fileChannelBackingCache = new
FileChannelBackingCache(this::findFile);
Review comment:
nit: make it final
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