How to use

enableIsolation

method

in

org.apache.accumulo.core.client.Scanner

private Iterator<Entry<Key,Value>> newIterator(Range r) {
 synchronized (scanner) {
  scanner.enableIsolation();
  scanner.setBatchSize(batchSize);
  scanner.setTimeout(timeout, TimeUnit.MILLISECONDS);
  scanner.setRange(r);
  scanner.setReadaheadThreshold(readaheadThreshold);
  setOptions((ScannerOptions) scanner, opts);
  return scanner.iterator();
  // return new FaultyIterator(scanner.iterator());
 }
}

smi.scanner.setReadaheadThreshold(readaheadThreshold);
if (isolated)
 smi.scanner.enableIsolation();
else
 smi.scanner.disableIsolation();

private Iterator<Entry<Key,Value>> newIterator(Range r) {
 synchronized (scanner) {
  scanner.enableIsolation();
  scanner.setBatchSize(batchSize);
  scanner.setTimeout(timeout, TimeUnit.MILLISECONDS);
  scanner.setRange(r);
  scanner.setReadaheadThreshold(readaheadThreshold);
  setOptions((ScannerOptions) scanner, opts);
  return scanner.iterator();
  // return new FaultyIterator(scanner.iterator());
 }
}

smi.scanner.setReadaheadThreshold(readaheadThreshold);
if (isolated)
 smi.scanner.enableIsolation();
else
 smi.scanner.disableIsolation();

@Test
public void testBugFix() throws Exception {
 // test bug fox for ACCUMULO-3977
 String table = super.getUniqueNames(1)[0];
 Connector conn = getConnector();
 conn.tableOperations().create(table);
 BatchWriter bw = conn.createBatchWriter(table, new BatchWriterConfig());
 addDocument(bw, "000A", "dog", "cat", "hamster", "iguana", "the");
 addDocument(bw, "000B", "java", "perl", "C++", "pascal", "the");
 addDocument(bw, "000C", "chrome", "firefox", "safari", "opera", "the");
 addDocument(bw, "000D", "logarithmic", "quadratic", "linear", "exponential", "the");
 bw.close();
 // its a bug when using rfiles, so flush
 conn.tableOperations().flush(table, null, null, true);
 IteratorSetting iterCfg = new IteratorSetting(30, "ayeaye",
   IntersectingIterator.class.getName());
 IntersectingIterator.setColumnFamilies(iterCfg,
   new Text[] {new Text("the"), new Text("hamster")});
 Scanner scanner = conn.createScanner(table, Authorizations.EMPTY);
 scanner.enableIsolation();
 scanner.addScanIterator(iterCfg);
 for (int i = 0; i < 100; i++) {
  Iterator<Entry<Key,Value>> iter = scanner.iterator();
  Assert.assertTrue(iter.hasNext());
  Assert.assertEquals("000A", iter.next().getKey().getColumnQualifierData().toString());
  Assert.assertFalse(iter.hasNext());
 }
}

public static void main(String[] args) throws Exception {
 ScanOpts opts = new ScanOpts();
 opts.parseArgs(Scan.class.getName(), args);
 Connector connector = opts.getConnector();
 Scanner scanner = connector.createScanner(opts.getTableName(), new Authorizations());
 if (opts.isolate) {
  scanner.enableIsolation();
 }
 Random tablet_index_generator = new Random(opts.scan_seed);
 LoopControl scanning_condition = opts.continuous ? new ContinuousLoopControl()
   : new IterativeLoopControl(opts.scan_iterations);
 while (scanning_condition.keepScanning()) {
  Range range = pickRange(connector.tableOperations(), opts.getTableName(),
    tablet_index_generator);
  scanner.setRange(range);
  if (opts.batch_size > 0) {
   scanner.setBatchSize(opts.batch_size);
  }
  try {
   consume(scanner);
  } catch (Exception e) {
   System.err.println(String.format(
     "Exception while scanning range %s. Check the state of Accumulo for errors.", range));
   throw e;
  }
 }
}