sijie commented on a change in pull request #513: BOOKKEEPER-1106: Introduce
write FileInfo cache and read FileInfo cache
URL: https://github.com/apache/bookkeeper/pull/513#discussion_r158333129
##########
File path:
bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/IndexPersistenceMgr.java
##########
@@ -100,71 +118,160 @@ public IndexPersistenceMgr(int pageSize,
getActiveLedgers();
ledgerDirsManager.addLedgerDirsListener(getLedgerDirsListener());
+ // build the file info cache
+ int concurrencyLevel = Math.max(1,
Math.max(conf.getNumAddWorkerThreads(), conf.getNumReadWorkerThreads()));
+ RemovalListener<Long, FileInfo> fileInfoEvictionListener =
this::handleLedgerEviction;
+ writeFileInfoCache = buildCache(
+ concurrencyLevel,
+ conf.getFileInfoCacheInitialCapacity(),
+ openFileLimit,
+ conf.getFileInfoMaxIdleTime(),
+ fileInfoEvictionListener);
+ readFileInfoCache = buildCache(
+ concurrencyLevel,
+ 2 * conf.getFileInfoCacheInitialCapacity(),
+ 2 * openFileLimit,
+ conf.getFileInfoMaxIdleTime(),
+ fileInfoEvictionListener);
+
// Expose Stats
evictedLedgersCounter =
statsLogger.getCounter(LEDGER_CACHE_NUM_EVICTED_LEDGERS);
- statsLogger.registerGauge(NUM_OPEN_LEDGERS, new Gauge<Integer>() {
+ pendingGetFileInfoCounter =
statsLogger.getCounter(PENDING_GET_FILE_INFO);
+ statsLogger.registerGauge(WRITE_FILE_INFO_CACHE_SIZE, new
Gauge<Number>() {
+ @Override
+ public Number getDefaultValue() {
+ return 0;
+ }
+
+ @Override
+ public Number getSample() {
+ return writeFileInfoCache.size();
+ }
+ });
+ statsLogger.registerGauge(READ_FILE_INFO_CACHE_SIZE, new
Gauge<Number>() {
@Override
- public Integer getDefaultValue() {
+ public Number getDefaultValue() {
return 0;
}
@Override
- public Integer getSample() {
- return getNumOpenLedgers();
+ public Number getSample() {
+ return readFileInfoCache.size();
}
});
}
- FileInfo getFileInfo(Long ledger, byte masterKey[]) throws IOException {
- FileInfo fi = fileInfoCache.get(ledger);
- if (null == fi) {
- boolean createdNewFile = false;
- File lf = null;
- synchronized (this) {
- // Check if the index file exists on disk.
- lf = findIndexFile(ledger);
- if (null == lf) {
- if (null == masterKey) {
- throw new Bookie.NoLedgerException(ledger);
+ private static Cache<Long, FileInfo> buildCache(int concurrencyLevel,
+ int initialCapacity,
+ int maximumSize,
+ long expireAfterAccessSeconds,
+ RemovalListener<Long, FileInfo>
removalListener) {
+ CacheBuilder<Long, FileInfo> builder = CacheBuilder.newBuilder()
+ .concurrencyLevel(concurrencyLevel)
+ .initialCapacity(initialCapacity)
+ .maximumSize(maximumSize)
+ .removalListener(removalListener);
+ if (expireAfterAccessSeconds > 0) {
+ builder.expireAfterAccess(expireAfterAccessSeconds,
TimeUnit.SECONDS);
+ }
+ return builder.build();
+ }
+
+ /**
+ * When a ledger is evicted, we need to make sure there's no other thread
+ * trying to get FileInfo for that ledger at the same time when we close
+ * the FileInfo.
+ */
+ private void handleLedgerEviction(RemovalNotification<Long, FileInfo>
notification) {
+ FileInfo fileInfo = notification.getValue();
+ Long ledgerId = notification.getKey();
+ if (null == fileInfo || null == notification.getKey()) {
+ return;
+ }
+ if (notification.wasEvicted()) {
+ evictedLedgersCounter.inc();
+ // we need to acquire the write lock in another thread,
+ // otherwise there could be dead lock happening.
+ evictionThreadPool.execute(() -> {
Review comment:
@ivankelly : I have the same feeling with @yzang. It can cause the case that
I described in my first comment here, and trigger this flaky test. but it won't
cause fence bit physically lost. I would suggest here if you think it will
lost, a test case is good to demonstrate the sequence.
I don't think this problem is particularly related to guava cache and
reference counting. this corner case exists even before guava cache change. It
will happens if there is concurrent loading and eviction.
regarding `FileInfo#close()`, it is my bad when introducing the
watcher/watchable. it is a change after guava cache, so we can move the
recycling logic to actual release.
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