anonymouscodeholic commented on a change in pull request #13393:
URL: https://github.com/apache/flink/pull/13393#discussion_r507679715
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File path:
flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBMemoryControllerUtils.java
##########
@@ -95,4 +95,45 @@ static Cache createCache(long cacheCapacity, double
highPriorityPoolRatio) {
static WriteBufferManager createWriteBufferManager(long
writeBufferManagerCapacity, Cache cache) {
return new WriteBufferManager(writeBufferManagerCapacity,
cache);
}
+
+ /**
+ * Calculate the default arena block size as RocksDB calculates it in
+ * <a
href="https://github.com/dataArtisans/frocksdb/blob/49bc897d5d768026f1eb816d960c1f2383396ef4/db/column_family.cc#L196"/>.
+ *
+ * @return the default arena block size
+ * @param writeBufferSize the write buffer size (bytes)
+ */
+ static long calculateRocksDBDefaultArenaBlockSize(long writeBufferSize)
{
+ return writeBufferSize / 8;
+ }
+
+ /**
+ * Calculate {@code mutable_limit_} as RocksDB calculates it in
+ * <a
href="https://github.com/dataArtisans/frocksdb/blob/FRocksDB-5.17.2/memtable/write_buffer_manager.cc#L54"/>.
+ *
+ * @param bufferSize write buffer size
+ * @return mutableLimit
+ */
+ static long calculateRocksDBMutableLimit(long bufferSize) {
+ return bufferSize * 7 / 8;
+ }
+
+ /**
+ * RocksDB starts flushing the active memtable constantly in the case
when the arena block size is greater than
+ * mutable limit (as calculated in {@link
#calculateRocksDBMutableLimit(long)}).
+ *
+ * <p>This happens because in such a case the check here
+ * <a
href="https://github.com/dataArtisans/frocksdb/blob/958f191d3f7276ae59b270f9db8390034d549ee0/include/rocksdb/write_buffer_manager.h#L47"/>
+ * is always true.
+ *
+ * <p>This method checks that arena block size is smaller than mutable
limit.
+ *
+ * @param arenaBlockSize Arena block size
+ * @param mutableLimit mutable limit
+ * @return whether arena block size is sensible
+ */
+ @VisibleForTesting
+ static boolean validateArenaBlockSize(long arenaBlockSize, long
mutableLimit) {
+ return arenaBlockSize < mutableLimit;
Review comment:
Yes, equal is OK.
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