Github user pnowojski commented on a diff in the pull request:
https://github.com/apache/flink/pull/6149#discussion_r195685352
--- Diff:
flink-core/src/test/java/org/apache/flink/core/fs/LimitedConnectionsFileSystemTest.java
---
@@ -122,6 +122,42 @@ public void testLimitingInputStreams() throws
Exception {
}
}
+ @Test
+ public void testLimitingRateLimitingStream() throws Exception {
+ final LimitedConnectionsFileSystem limitedFs = new
LimitedConnectionsFileSystem(
+ LocalFileSystem.getSharedInstance(),
+ Integer.MAX_VALUE,
+ Integer.MAX_VALUE,
+ Integer.MAX_VALUE,
+ 0,
+ 0,
+ 10000, // Limit write to 10 kbytes/s
+ 10000); // Limit read to 10 kbytes/s
+ File file = tempFolder.newFile();
+ Path path = new Path(file.toURI());
+ long durationWrite = System.currentTimeMillis();
+ try (FSDataOutputStream stream = limitedFs.create(path,
WriteMode.OVERWRITE)) {
+ final Random rnd = new Random();
+ final byte[] data = new byte[100];
+ for (int i = 0; i < (1000 + 10); i++) {
+ rnd.nextBytes(data);
+ stream.write(data);
+ }
+ }
+ durationWrite = System.currentTimeMillis() - durationWrite;
+
+ long durationRead = System.currentTimeMillis();
+ final byte[] data = new byte[100];
+ try (FSDataInputStream stream = limitedFs.open(path)) {
+ //noinspection StatementWithEmptyBody
+ while (stream.read(data) != -1) {}
+ }
+ durationRead = System.currentTimeMillis() - durationRead;
+ file.delete();
+ assertTrue(durationWrite > 10000);
+ assertTrue(durationRead > 8000); // Less stability with read
limiter than write
--- End diff --
I think burst credits are accumulated over time. If you create RateLimiter
in `LimitedConnectionsFileSystem` constructor and immediately start using the
output rate limiter, it will not have any burst credits accumulated. However
input rate limiter will be used only after couple of seconds (when write has
finished), thus it will accumulate burst credits.
Btw, that makes me thing, do we really want to have two separate limiters
for read and writes? Are the quotas on S3 accounted also separately? Or usually
is there a single quota for reads and writes together? If the latter one, it
would be more handy to have one shared `RateLimiter` between reads and writes.
---
