Limit read-ahead bytes to the size of the read cache (#2647)
* Limit read-ahead bytes to the size of the read cache
* Update bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/storage/ldb/SingleDirectoryDbLedgerStorage.java
Co-authored-by: lipenghui <penghui@apache.org>
Co-authored-by: lipenghui <penghui@apache.org>
diff --git a/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/storage/ldb/SingleDirectoryDbLedgerStorage.java b/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/storage/ldb/SingleDirectoryDbLedgerStorage.java
index 0ac898c..94904be 100644
--- a/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/storage/ldb/SingleDirectoryDbLedgerStorage.java
+++ b/bookkeeper-server/src/main/java/org/apache/bookkeeper/bookie/storage/ldb/SingleDirectoryDbLedgerStorage.java
@@ -134,6 +134,8 @@
private static final long DEFAULT_MAX_THROTTLE_TIME_MILLIS = TimeUnit.SECONDS.toMillis(10);
+ private final long maxReadAheadBytesSize;
+
public SingleDirectoryDbLedgerStorage(ServerConfiguration conf, LedgerManager ledgerManager,
LedgerDirsManager ledgerDirsManager, LedgerDirsManager indexDirsManager, StateManager stateManager,
CheckpointSource checkpointSource, Checkpointer checkpointer, StatsLogger statsLogger,
@@ -155,6 +157,9 @@
readCacheMaxSize = readCacheSize;
readAheadCacheBatchSize = conf.getInt(READ_AHEAD_CACHE_BATCH_SIZE, DEFAULT_READ_AHEAD_CACHE_BATCH_SIZE);
+ // Do not attempt to perform read-ahead more than half the total size of the cache
+ maxReadAheadBytesSize = readCacheMaxSize / 2;
+
long maxThrottleTimeMillis = conf.getLong(DbLedgerStorage.MAX_THROTTLE_TIME_MILLIS,
DEFAULT_MAX_THROTTLE_TIME_MILLIS);
maxThrottleTimeNanos = TimeUnit.MILLISECONDS.toNanos(maxThrottleTimeMillis);
@@ -469,7 +474,9 @@
int count = 0;
long size = 0;
- while (count < readAheadCacheBatchSize && currentEntryLogId == firstEntryLogId) {
+ while (count < readAheadCacheBatchSize
+ && size < maxReadAheadBytesSize
+ && currentEntryLogId == firstEntryLogId) {
ByteBuf entry = entryLogger.internalReadEntry(orginalLedgerId, firstEntryId, currentEntryLocation,
false /* validateEntry */);
