ivankelly 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_r158281218
##########
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:
@yzang @sijie
Ended up going down a rabbithole on this today and there's more ways for
this to break.
When getFileInfo gives out a FileInfo object, it increases the refcount. If
the cache evicts or expires before the caller of getFileInfo is finished, the
flush can occur before modifications take place (such as setFenced), this
setFenced can be lost, as the final release will not close the file handle.
Going to put it down for today though, because it has my head fried.
I don't think guava cache is enough for this. We need something that is
aware of reference counts, and gives us control of locking. It shouldn't be
super hard, but will end up touching a lot of this code.
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