Examples with S3AInputStream org.apache.hadoop.fs.s3a.S3AInputStream used on opensource projects

Example 1 with S3AInputStream

use of org.apache.hadoop.fs.s3a.S3AInputStream in project hadoop by apache.

the class ITestS3AInputStreamPerformance method testRandomReadOverBuffer.

@Test
public void testRandomReadOverBuffer() throws Throwable {
    describe("read over a buffer, making sure that the requests" + " spans readahead ranges");
    int datasetLen = _32K;
    S3AFileSystem fs = getFileSystem();
    Path dataFile = path("testReadOverBuffer.bin");
    byte[] sourceData = dataset(datasetLen, 0, 64);
    // relies on the field 'fs' referring to the R/W FS
    writeDataset(fs, dataFile, sourceData, datasetLen, _16K, true);
    byte[] buffer = new byte[datasetLen];
    int readahead = _8K;
    int halfReadahead = _4K;
    in = openDataFile(fs, dataFile, S3AInputPolicy.Random, readahead);
    LOG.info("Starting initial reads");
    S3AInputStream s3aStream = getS3aStream();
    assertEquals(readahead, s3aStream.getReadahead());
    byte[] oneByte = new byte[1];
    assertEquals(1, in.read(0, oneByte, 0, 1));
    // make some assertions about the current state
    assertEquals("remaining in\n" + in, readahead - 1, s3aStream.remainingInCurrentRequest());
    assertEquals("range start in\n" + in, 0, s3aStream.getContentRangeStart());
    assertEquals("range finish in\n" + in, readahead, s3aStream.getContentRangeFinish());
    assertStreamOpenedExactlyOnce();
    describe("Starting sequence of positioned read calls over\n%s", in);
    NanoTimer readTimer = new NanoTimer();
    int currentPos = halfReadahead;
    int offset = currentPos;
    int bytesRead = 0;
    int readOps = 0;
    // make multiple read() calls
    while (bytesRead < halfReadahead) {
        int length = buffer.length - offset;
        int read = in.read(currentPos, buffer, offset, length);
        bytesRead += read;
        offset += read;
        readOps++;
        assertEquals("open operations on request #" + readOps + " after reading " + bytesRead + " current position in stream " + currentPos + " in\n" + fs + "\n " + in, 1, streamStatistics.openOperations);
        for (int i = currentPos; i < currentPos + read; i++) {
            assertEquals("Wrong value from byte " + i, sourceData[i], buffer[i]);
        }
        currentPos += read;
    }
    assertStreamOpenedExactlyOnce();
    // assert at the end of the original block
    assertEquals(readahead, currentPos);
    readTimer.end("read %d in %d operations", bytesRead, readOps);
    bandwidth(readTimer, bytesRead);
    LOG.info("Time per byte(): {} nS", toHuman(readTimer.nanosPerOperation(bytesRead)));
    LOG.info("Time per read(): {} nS", toHuman(readTimer.nanosPerOperation(readOps)));
    describe("read last byte");
    // read one more
    int read = in.read(currentPos, buffer, bytesRead, 1);
    assertTrue("-1 from last read", read >= 0);
    assertOpenOperationCount(2);
    assertEquals("Wrong value from read ", sourceData[currentPos], (int) buffer[currentPos]);
    currentPos++;
    // now scan all the way to the end of the file, using single byte read()
    // calls
    describe("read() to EOF over \n%s", in);
    long readCount = 0;
    NanoTimer timer = new NanoTimer();
    LOG.info("seeking");
    in.seek(currentPos);
    LOG.info("reading");
    while (currentPos < datasetLen) {
        int r = in.read();
        assertTrue("Negative read() at position " + currentPos + " in\n" + in, r >= 0);
        buffer[currentPos] = (byte) r;
        assertEquals("Wrong value from read from\n" + in, sourceData[currentPos], r);
        currentPos++;
        readCount++;
    }
    timer.end("read %d bytes", readCount);
    bandwidth(timer, readCount);
    LOG.info("Time per read(): {} nS", toHuman(timer.nanosPerOperation(readCount)));
    assertEquals("last read in " + in, -1, in.read());
}