Merge 459d930bd9 into 209ef2b6c4

conf/cassandra.yaml

@@ -952,6 +952,8 @@ index_summary_resize_interval: 60m
 # impacting read latencies. Almost always a good idea on SSDs; not
 # necessarily on platters.
 trickle_fsync: false
+# The interval is counted in uncompressed bytes, so for compressed SSTables
+# (the default) an fsync fires after fewer bytes than this reach the disk.
 # Min unit: KiB
 trickle_fsync_interval: 10240KiB
 

test/unit/org/apache/cassandra/io/compress/CompressedSequentialWriterTest.java

@@ -167,6 +167,7 @@ public class CompressedSequentialWriterTest extends SequentialWriterTest
 
         File on = FileUtils.createTempFile("trickleFsyncOn", "1");
         File onOffsets = new File(on.path() + ".metadata");
+        // The interval counts uncompressed input bytes, so chunk*20 written past a chunk*4 interval must sync.
         SequentialWriterOption enabled = SequentialWriterOption.newBuilder()
                                                                .trickleFsync(true)
                                                                .trickleFsyncByteInterval(chunk * 4)
@@ -182,6 +183,13 @@ public class CompressedSequentialWriterTest extends SequentialWriterTest
             on.tryDelete();
             onOffsets.tryDelete();
         }
+    }
+
+    @Test
+    public void testTrickleFsyncDoesNotFireWhenDisabled() throws IOException
+    {
+        int chunk = 4096;
+        MetadataCollector collector = new MetadataCollector(new ClusteringComparator(UTF8Type.instance));
 
         File off = FileUtils.createTempFile("trickleFsyncOff", "1");
         File offOffsets = new File(off.path() + ".metadata");