[GitHub] [hbase] javierluca commented on a change in pull request #1781: HBASE-24435 Add hedgedReads and hedgedReadWins count metrics
javierluca commented on a change in pull request #1781:
URL: https://github.com/apache/hbase/pull/1781#discussion_r430932500
##
File path:
hbase-server/src/test/java/org/apache/hadoop/hbase/util/TestFSUtils.java
##
@@ -435,4 +440,145 @@ public void
checkStreamCapabilitiesOnHdfsDataOutputStream() throws Exception {
}
}
+ /**
+ * Ugly test that ensures we can get at the hedged read counters in
dfsclient.
+ * Does a bit of preading with hedged reads enabled using code taken from
hdfs TestPread.
+ */
+ @Test public void testDFSHedgedReadMetrics() throws Exception {
+HBaseTestingUtility htu = new HBaseTestingUtility();
+// Enable hedged reads and set it so the threshold is really low.
+// Most of this test is taken from HDFS, from TestPread.
+Configuration conf = htu.getConfiguration();
+conf.setInt(DFSConfigKeys.DFS_DFSCLIENT_HEDGED_READ_THREADPOOL_SIZE, 5);
+conf.setLong(DFSConfigKeys.DFS_DFSCLIENT_HEDGED_READ_THRESHOLD_MILLIS, 0);
+conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, 4096);
+conf.setLong(DFSConfigKeys.DFS_CLIENT_READ_PREFETCH_SIZE_KEY, 4096);
+// Set short retry timeouts so this test runs faster
+conf.setInt(DFSConfigKeys.DFS_CLIENT_RETRY_WINDOW_BASE, 0);
+conf.setBoolean("dfs.datanode.transferTo.allowed", false);
+MiniDFSCluster cluster = new
MiniDFSCluster.Builder(conf).numDataNodes(3).build();
+// Get the metrics. Should be empty.
+DFSHedgedReadMetrics metrics = FSUtils.getDFSHedgedReadMetrics(conf);
+assertEquals(0, metrics.getHedgedReadOps());
+FileSystem fileSys = cluster.getFileSystem();
+try {
+ Path p = new Path("preadtest.dat");
+ // We need > 1 blocks to test out the hedged reads.
+ DFSTestUtil.createFile(fileSys, p, 12 * blockSize, 12 * blockSize,
+blockSize, (short) 3, seed);
+ pReadFile(fileSys, p);
+ cleanupFile(fileSys, p);
+ assertTrue(metrics.getHedgedReadOps() > 0);
+} finally {
+ fileSys.close();
+ cluster.shutdown();
+}
+ }
+
+ // Below is taken from TestPread over in HDFS.
+ static final int blockSize = 4096;
+ static final long seed = 0xDEADBEEFL;
+
+ private void pReadFile(FileSystem fileSys, Path name) throws IOException {
+FSDataInputStream stm = fileSys.open(name);
+byte[] expected = new byte[12 * blockSize];
+Random rand = new Random(seed);
+rand.nextBytes(expected);
+// do a sanity check. Read first 4K bytes
+byte[] actual = new byte[4096];
+stm.readFully(actual);
+checkAndEraseData(actual, 0, expected, "Read Sanity Test");
+// now do a pread for the first 8K bytes
+actual = new byte[8192];
+doPread(stm, 0L, actual, 0, 8192);
+checkAndEraseData(actual, 0, expected, "Pread Test 1");
+// Now check to see if the normal read returns 4K-8K byte range
+actual = new byte[4096];
+stm.readFully(actual);
+checkAndEraseData(actual, 4096, expected, "Pread Test 2");
+// Now see if we can cross a single block boundary successfully
+// read 4K bytes from blockSize - 2K offset
+stm.readFully(blockSize - 2048, actual, 0, 4096);
+checkAndEraseData(actual, (blockSize - 2048), expected, "Pread Test 3");
+// now see if we can cross two block boundaries successfully
+// read blockSize + 4K bytes from blockSize - 2K offset
+actual = new byte[blockSize + 4096];
+stm.readFully(blockSize - 2048, actual);
+checkAndEraseData(actual, (blockSize - 2048), expected, "Pread Test 4");
+// now see if we can cross two block boundaries that are not cached
+// read blockSize + 4K bytes from 10*blockSize - 2K offset
+actual = new byte[blockSize + 4096];
+stm.readFully(10 * blockSize - 2048, actual);
+checkAndEraseData(actual, (10 * blockSize - 2048), expected, "Pread Test
5");
+// now check that even after all these preads, we can still read
+// bytes 8K-12K
+actual = new byte[4096];
+stm.readFully(actual);
+checkAndEraseData(actual, 8192, expected, "Pread Test 6");
+// done
+stm.close();
+// check block location caching
+stm = fileSys.open(name);
+stm.readFully(1, actual, 0, 4096);
+stm.readFully(4*blockSize, actual, 0, 4096);
+stm.readFully(7*blockSize, actual, 0, 4096);
+actual = new byte[3*4096];
+stm.readFully(0*blockSize, actual, 0, 3*4096);
+checkAndEraseData(actual, 0, expected, "Pread Test 7");
+actual = new byte[8*4096];
+stm.readFully(3*blockSize, actual, 0, 8*4096);
+checkAndEraseData(actual, 3*blockSize, expected, "Pread Test 8");
+// read the tail
+stm.readFully(11*blockSize+blockSize/2, actual, 0, blockSize/2);
+IOException res = null;
+try { // read beyond the end of the file
+ stm.readFully(11*blockSize+blockSize/2, actual, 0, blockSize);
+} catch (IOException e) {
+ // should throw an exception
+ res = e;
+}
+assertTrue("Error reading beyond file boundary.", res != null);
+
+
[GitHub] [hbase] javierluca commented on a change in pull request #1781: HBASE-24435 Add hedgedReads and hedgedReadWins count metrics
javierluca commented on a change in pull request #1781:
URL: https://github.com/apache/hbase/pull/1781#discussion_r430932500
##
File path:
hbase-server/src/test/java/org/apache/hadoop/hbase/util/TestFSUtils.java
##
@@ -435,4 +440,145 @@ public void
checkStreamCapabilitiesOnHdfsDataOutputStream() throws Exception {
}
}
+ /**
+ * Ugly test that ensures we can get at the hedged read counters in
dfsclient.
+ * Does a bit of preading with hedged reads enabled using code taken from
hdfs TestPread.
+ */
+ @Test public void testDFSHedgedReadMetrics() throws Exception {
+HBaseTestingUtility htu = new HBaseTestingUtility();
+// Enable hedged reads and set it so the threshold is really low.
+// Most of this test is taken from HDFS, from TestPread.
+Configuration conf = htu.getConfiguration();
+conf.setInt(DFSConfigKeys.DFS_DFSCLIENT_HEDGED_READ_THREADPOOL_SIZE, 5);
+conf.setLong(DFSConfigKeys.DFS_DFSCLIENT_HEDGED_READ_THRESHOLD_MILLIS, 0);
+conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, 4096);
+conf.setLong(DFSConfigKeys.DFS_CLIENT_READ_PREFETCH_SIZE_KEY, 4096);
+// Set short retry timeouts so this test runs faster
+conf.setInt(DFSConfigKeys.DFS_CLIENT_RETRY_WINDOW_BASE, 0);
+conf.setBoolean("dfs.datanode.transferTo.allowed", false);
+MiniDFSCluster cluster = new
MiniDFSCluster.Builder(conf).numDataNodes(3).build();
+// Get the metrics. Should be empty.
+DFSHedgedReadMetrics metrics = FSUtils.getDFSHedgedReadMetrics(conf);
+assertEquals(0, metrics.getHedgedReadOps());
+FileSystem fileSys = cluster.getFileSystem();
+try {
+ Path p = new Path("preadtest.dat");
+ // We need > 1 blocks to test out the hedged reads.
+ DFSTestUtil.createFile(fileSys, p, 12 * blockSize, 12 * blockSize,
+blockSize, (short) 3, seed);
+ pReadFile(fileSys, p);
+ cleanupFile(fileSys, p);
+ assertTrue(metrics.getHedgedReadOps() > 0);
+} finally {
+ fileSys.close();
+ cluster.shutdown();
+}
+ }
+
+ // Below is taken from TestPread over in HDFS.
+ static final int blockSize = 4096;
+ static final long seed = 0xDEADBEEFL;
+
+ private void pReadFile(FileSystem fileSys, Path name) throws IOException {
+FSDataInputStream stm = fileSys.open(name);
+byte[] expected = new byte[12 * blockSize];
+Random rand = new Random(seed);
+rand.nextBytes(expected);
+// do a sanity check. Read first 4K bytes
+byte[] actual = new byte[4096];
+stm.readFully(actual);
+checkAndEraseData(actual, 0, expected, "Read Sanity Test");
+// now do a pread for the first 8K bytes
+actual = new byte[8192];
+doPread(stm, 0L, actual, 0, 8192);
+checkAndEraseData(actual, 0, expected, "Pread Test 1");
+// Now check to see if the normal read returns 4K-8K byte range
+actual = new byte[4096];
+stm.readFully(actual);
+checkAndEraseData(actual, 4096, expected, "Pread Test 2");
+// Now see if we can cross a single block boundary successfully
+// read 4K bytes from blockSize - 2K offset
+stm.readFully(blockSize - 2048, actual, 0, 4096);
+checkAndEraseData(actual, (blockSize - 2048), expected, "Pread Test 3");
+// now see if we can cross two block boundaries successfully
+// read blockSize + 4K bytes from blockSize - 2K offset
+actual = new byte[blockSize + 4096];
+stm.readFully(blockSize - 2048, actual);
+checkAndEraseData(actual, (blockSize - 2048), expected, "Pread Test 4");
+// now see if we can cross two block boundaries that are not cached
+// read blockSize + 4K bytes from 10*blockSize - 2K offset
+actual = new byte[blockSize + 4096];
+stm.readFully(10 * blockSize - 2048, actual);
+checkAndEraseData(actual, (10 * blockSize - 2048), expected, "Pread Test
5");
+// now check that even after all these preads, we can still read
+// bytes 8K-12K
+actual = new byte[4096];
+stm.readFully(actual);
+checkAndEraseData(actual, 8192, expected, "Pread Test 6");
+// done
+stm.close();
+// check block location caching
+stm = fileSys.open(name);
+stm.readFully(1, actual, 0, 4096);
+stm.readFully(4*blockSize, actual, 0, 4096);
+stm.readFully(7*blockSize, actual, 0, 4096);
+actual = new byte[3*4096];
+stm.readFully(0*blockSize, actual, 0, 3*4096);
+checkAndEraseData(actual, 0, expected, "Pread Test 7");
+actual = new byte[8*4096];
+stm.readFully(3*blockSize, actual, 0, 8*4096);
+checkAndEraseData(actual, 3*blockSize, expected, "Pread Test 8");
+// read the tail
+stm.readFully(11*blockSize+blockSize/2, actual, 0, blockSize/2);
+IOException res = null;
+try { // read beyond the end of the file
+ stm.readFully(11*blockSize+blockSize/2, actual, 0, blockSize);
+} catch (IOException e) {
+ // should throw an exception
+ res = e;
+}
+assertTrue("Error reading beyond file boundary.", res != null);
+
+
[GitHub] [hbase] javierluca commented on a change in pull request #1781: HBASE-24435 Add hedgedReads and hedgedReadWins count metrics
javierluca commented on a change in pull request #1781:
URL: https://github.com/apache/hbase/pull/1781#discussion_r430833826
##
File path:
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionServerWrapperImpl.java
##
@@ -819,6 +832,16 @@ public long getZeroCopyBytesRead() {
return FSDataInputStreamWrapper.getZeroCopyBytesRead();
}
+ @Override
+ public long getHedgedReadOps() {
+return this.dfsHedgedReadMetrics == null? 0 :
this.dfsHedgedReadMetrics.getHedgedReadOps();
Review comment:
sorry about that, fixing
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