Examples with StreamEventsResult com.linkedin.databus.core.StreamEventsResult used on opensource projects

Example 1 with StreamEventsResult

use of com.linkedin.databus.core.StreamEventsResult in project databus by linkedin.

the class TestGenericDispatcher method testPartialWindowRollback.

@Test(groups = { "small", "functional" })
public /**
 * Tests the case where the dispatcher exits the main processing loop in {@link GenericDispatcher#doDispatchEvents()}
 * with a partial window and the flushing of the outstanding callbacks fails. We want to make sure that a rollback
 * is correctly triggered.
 *
 * The test simulates the following case: e1_1 e1_2 e1_3 <EOW> e2_1 e2_2 e2_3 <EOW> ... with a failure in the e2_2
 * callback.
 *
 * 1) Read full first window: e1_1 e1_2 e1_3 <EOW>
 * 2) Read partial second window: e2_1 e2_2
 * 3) The above should fail -- verify that rollback is called
 * 4) Read the rest
 */
void testPartialWindowRollback() throws Exception {
    final Logger log = Logger.getLogger("TestGenericDispatcher.testPartialWindowRollback");
    // log.setLevel(Level.INFO);
    log.info("start");
    final Level saveLevel = Logger.getLogger("com.linkedin.databus.client").getLevel();
    // Logger.getLogger("com.linkedin.databus.client").setLevel(Level.DEBUG);
    // generate events
    Vector<Short> srcIdList = new Vector<Short>();
    srcIdList.add((short) 1);
    DbusEventGenerator evGen = new DbusEventGenerator(0, srcIdList);
    Vector<DbusEvent> srcTestEvents = new Vector<DbusEvent>();
    final int numEvents = 9;
    // 1-based number of the event callback to fail
    final int numOfFailureEvent = 5;
    final int numEventsPerWindow = 3;
    final int payloadSize = 200;
    final int numWindows = (int) Math.ceil(1.0 * numEvents / numEventsPerWindow);
    Assert.assertTrue(evGen.generateEvents(numEvents, numEventsPerWindow, 500, payloadSize, srcTestEvents) > 0);
    // find out how much data we need to stream for the failure
    // account for the EOW event which is < payload size
    int win1Size = payloadSize - 1;
    int win2Size = 0;
    int eventN = 0;
    for (DbusEvent e : srcTestEvents) {
        eventN++;
        if (eventN <= numEventsPerWindow) {
            win1Size += e.size();
        } else if (eventN <= numOfFailureEvent) {
            win2Size += e.size();
        }
    }
    // serialize the events to a buffer so they can be sent to the client
    final TestGenericDispatcherEventBuffer srcEventsBuf = new TestGenericDispatcherEventBuffer(_generic100KBufferStaticConfig);
    DbusEventAppender eventProducer = new DbusEventAppender(srcTestEvents, srcEventsBuf, null, true);
    Thread tEmitter = new Thread(eventProducer);
    tEmitter.start();
    // Create destination (client) buffer
    final TestGenericDispatcherEventBuffer destEventsBuf = new TestGenericDispatcherEventBuffer(_generic100KBufferStaticConfig);
    // Create dispatcher
    final TimeoutTestConsumer mockConsumer = new TimeoutTestConsumer(100, 10, 0, numOfFailureEvent, 0, 1);
    SelectingDatabusCombinedConsumer sdccMockConsumer = new SelectingDatabusCombinedConsumer((DatabusStreamConsumer) mockConsumer);
    List<String> sources = new ArrayList<String>();
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    for (int i = 1; i <= 3; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    DatabusV2ConsumerRegistration consumerReg = new DatabusV2ConsumerRegistration(sdccMockConsumer, sources, null);
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg);
    final ConsumerCallbackStats callbackStats = new ConsumerCallbackStats(0, "test", "test", true, false, null);
    final UnifiedClientStats unifiedStats = new UnifiedClientStats(0, "test", "test.unified");
    MultiConsumerCallback callback = new MultiConsumerCallback(allRegistrations, Executors.newFixedThreadPool(2), 1000, new StreamConsumerCallbackFactory(callbackStats, unifiedStats), callbackStats, unifiedStats, null, null);
    callback.setSourceMap(sourcesMap);
    List<DatabusSubscription> subs = DatabusSubscription.createSubscriptionList(sources);
    final RelayDispatcher dispatcher = new RelayDispatcher("dispatcher", _genericRelayConnStaticConfig, subs, new InMemoryPersistenceProvider(), destEventsBuf, callback, null, null, null, null, null);
    dispatcher.setSchemaIdCheck(false);
    Thread dispatcherThread = new Thread(dispatcher);
    dispatcherThread.setDaemon(true);
    log.info("starting dispatcher thread");
    dispatcherThread.start();
    HashMap<Long, List<RegisterResponseEntry>> schemaMap = new HashMap<Long, List<RegisterResponseEntry>>();
    List<RegisterResponseEntry> l1 = new ArrayList<RegisterResponseEntry>();
    List<RegisterResponseEntry> l2 = new ArrayList<RegisterResponseEntry>();
    List<RegisterResponseEntry> l3 = new ArrayList<RegisterResponseEntry>();
    l1.add(new RegisterResponseEntry(1L, (short) 1, SOURCE1_SCHEMA_STR));
    l2.add(new RegisterResponseEntry(2L, (short) 1, SOURCE2_SCHEMA_STR));
    l3.add(new RegisterResponseEntry(3L, (short) 1, SOURCE3_SCHEMA_STR));
    schemaMap.put(1L, l1);
    schemaMap.put(2L, l2);
    schemaMap.put(3L, l3);
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesIdsMessage(sourcesMap.values()));
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesSchemasMessage(schemaMap));
    log.info("starting event dispatch");
    // stream the events from the source buffer without the EOW
    // comm channels between reader and writer
    Pipe pipe = Pipe.open();
    Pipe.SinkChannel writerStream = pipe.sink();
    Pipe.SourceChannel readerStream = pipe.source();
    writerStream.configureBlocking(true);
    readerStream.configureBlocking(false);
    // Event writer - Relay in the real world
    Checkpoint cp = Checkpoint.createFlexibleCheckpoint();
    // Event readers - Clients in the real world
    // Checkpoint pullerCheckpoint = Checkpoint.createFlexibleCheckpoint();
    DbusEventsStatisticsCollector clientStats = new DbusEventsStatisticsCollector(0, "client", true, false, null);
    DbusEventBufferReader reader = new DbusEventBufferReader(destEventsBuf, readerStream, null, clientStats);
    UncaughtExceptionTrackingThread tReader = new UncaughtExceptionTrackingThread(reader, "Reader");
    tReader.setDaemon(true);
    tReader.start();
    try {
        log.info("send first window -- that one should be OK");
        StreamEventsResult streamRes = srcEventsBuf.streamEvents(cp, writerStream, new StreamEventsArgs(win1Size));
        Assert.assertEquals(numEventsPerWindow + 1, streamRes.getNumEventsStreamed());
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return 1 == callbackStats.getNumSysEventsProcessed();
            }
        }, "first window processed", 5000, log);
        log.info("send the second partial window -- that one should cause an error");
        streamRes = srcEventsBuf.streamEvents(cp, writerStream, new StreamEventsArgs(win2Size));
        Assert.assertEquals(numOfFailureEvent - numEventsPerWindow, streamRes.getNumEventsStreamed());
        log.info("wait for dispatcher to finish");
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                log.info("events received: " + callbackStats.getNumDataEventsReceived());
                return numOfFailureEvent <= callbackStats.getNumDataEventsProcessed();
            }
        }, "all events until the error processed", 5000, log);
        log.info("all data events have been received but no EOW");
        Assert.assertEquals(numOfFailureEvent, clientStats.getTotalStats().getNumDataEvents());
        Assert.assertEquals(1, clientStats.getTotalStats().getNumSysEvents());
        // at least one failing event therefore < numOfFailureEvent events can be processed
        Assert.assertTrue(numOfFailureEvent <= callbackStats.getNumDataEventsProcessed());
        // onDataEvent callbacks for e2_1 and e2_2 get cancelled
        Assert.assertEquals(2, callbackStats.getNumDataErrorsProcessed());
        // only one EOW
        Assert.assertEquals(1, callbackStats.getNumSysEventsProcessed());
        log.info("Send the remainder of the window");
        streamRes = srcEventsBuf.streamEvents(cp, writerStream, new StreamEventsArgs(100000));
        // remaining events + EOWs
        Assert.assertEquals(srcTestEvents.size() + numWindows - (numOfFailureEvent + 1), streamRes.getNumEventsStreamed());
        log.info("wait for the rollback");
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return 1 == mockConsumer.getNumRollbacks();
            }
        }, "rollback seen", 5000, log);
        log.info("wait for dispatcher to finish after the rollback");
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                log.info("num windows processed: " + callbackStats.getNumSysEventsProcessed());
                return numWindows == callbackStats.getNumSysEventsProcessed();
            }
        }, "all events processed", 5000, log);
    } finally {
        reader.stop();
        dispatcher.shutdown();
        log.info("all events processed");
        verifyNoLocks(null, srcEventsBuf);
        verifyNoLocks(null, destEventsBuf);
    }
    Logger.getLogger("com.linkedin.databus.client").setLevel(saveLevel);
    log.info("end\n");
}

Example 2 with StreamEventsResult

use of com.linkedin.databus.core.StreamEventsResult in project databus by linkedin.

the class TestGenericDispatcher method testShutdownBeforeRollback.

@Test(groups = { "small", "functional" })
public /**
 * 1. Dispatcher is dispatching 2 window of events.
 * 2. First window consumption is successfully done.
 * 3. The second window's onStartDataEventSequence() of the callback registered is blocked (interruptible),
 *    causing the dispatcher to wait.
 * 4. At this instant the dispatcher is shut down. The callback is made to return Failure status which would
 *    cause rollback in normal scenario.
 * 5. As the shutdown message is passed, the blocked callback is expected to be interrupted and no rollback
 *    calls MUST be made.
 */
void testShutdownBeforeRollback() throws Exception {
    final Logger log = Logger.getLogger("TestGenericDispatcher.testShutdownBeforeRollback");
    log.setLevel(Level.INFO);
    // log.getRoot().setLevel(Level.DEBUG);
    LOG.info("start");
    // generate events
    Vector<Short> srcIdList = new Vector<Short>();
    srcIdList.add((short) 1);
    DbusEventGenerator evGen = new DbusEventGenerator(0, srcIdList);
    Vector<DbusEvent> srcTestEvents = new Vector<DbusEvent>();
    final int numEvents = 8;
    final int numEventsPerWindow = 4;
    final int payloadSize = 200;
    Assert.assertTrue(evGen.generateEvents(numEvents, numEventsPerWindow, 500, payloadSize, srcTestEvents) > 0);
    // find out how much data we need to stream for the failure
    // account for the EOW event which is < payload size
    int win1Size = payloadSize - 1;
    for (DbusEvent e : srcTestEvents) {
        win1Size += e.size();
    }
    // serialize the events to a buffer so they can be sent to the client
    final TestGenericDispatcherEventBuffer srcEventsBuf = new TestGenericDispatcherEventBuffer(_generic100KBufferStaticConfig);
    DbusEventAppender eventProducer = new DbusEventAppender(srcTestEvents, srcEventsBuf, null, true);
    Thread tEmitter = new Thread(eventProducer);
    tEmitter.start();
    // Create destination (client) buffer
    final TestGenericDispatcherEventBuffer destEventsBuf = new TestGenericDispatcherEventBuffer(_generic100KBufferStaticConfig);
    /**
     *  Consumer with ability to wait for latch during onStartDataEventSequence()
     */
    class TimeoutDESConsumer extends TimeoutTestConsumer {

        private final CountDownLatch latch = new CountDownLatch(1);

        private int _countStartWindow = 0;

        private final int _failedRequestNumber;

        public TimeoutDESConsumer(int failedRequestNumber) {
            super(1, 1, 0, 0, 0, 0);
            _failedRequestNumber = failedRequestNumber;
        }

        public CountDownLatch getLatch() {
            return latch;
        }

        @Override
        public ConsumerCallbackResult onStartDataEventSequence(SCN startScn) {
            _countStartWindow++;
            if (_countStartWindow == _failedRequestNumber) {
                // Wait for the latch to open
                try {
                    latch.await();
                } catch (InterruptedException e) {
                }
                return ConsumerCallbackResult.ERROR_FATAL;
            }
            return super.onStartDataEventSequence(startScn);
        }

        @Override
        public ConsumerCallbackResult onDataEvent(DbusEvent e, DbusEventDecoder eventDecoder) {
            return ConsumerCallbackResult.SUCCESS;
        }

        public int getNumBeginWindowCalls() {
            return _countStartWindow;
        }
    }
    // Create dispatcher
    // fail on second window
    final TimeoutDESConsumer mockConsumer = new TimeoutDESConsumer(2);
    SelectingDatabusCombinedConsumer sdccMockConsumer = new SelectingDatabusCombinedConsumer((DatabusStreamConsumer) mockConsumer);
    List<String> sources = new ArrayList<String>();
    Map<Long, IdNamePair> sourcesMap = new HashMap<Long, IdNamePair>();
    for (int i = 1; i <= 3; ++i) {
        IdNamePair sourcePair = new IdNamePair((long) i, "source" + i);
        sources.add(sourcePair.getName());
        sourcesMap.put(sourcePair.getId(), sourcePair);
    }
    DatabusV2ConsumerRegistration consumerReg = new DatabusV2ConsumerRegistration(sdccMockConsumer, sources, null);
    List<DatabusV2ConsumerRegistration> allRegistrations = Arrays.asList(consumerReg);
    final ConsumerCallbackStats callbackStats = new ConsumerCallbackStats(0, "test", "test", true, false, null);
    final UnifiedClientStats unifiedStats = new UnifiedClientStats(0, "test", "test.unified");
    MultiConsumerCallback callback = new MultiConsumerCallback(allRegistrations, Executors.newFixedThreadPool(2), // 100 ms budget
    100, new StreamConsumerCallbackFactory(callbackStats, unifiedStats), callbackStats, unifiedStats, null, null);
    callback.setSourceMap(sourcesMap);
    List<DatabusSubscription> subs = DatabusSubscription.createSubscriptionList(sources);
    final RelayDispatcher dispatcher = new RelayDispatcher("dispatcher", _genericRelayConnStaticConfig, subs, new InMemoryPersistenceProvider(), destEventsBuf, callback, null, null, null, null, null);
    final Thread dispatcherThread = new Thread(dispatcher);
    log.info("starting dispatcher thread");
    dispatcherThread.start();
    // Generate RegisterRespone for schema
    HashMap<Long, List<RegisterResponseEntry>> schemaMap = new HashMap<Long, List<RegisterResponseEntry>>();
    List<RegisterResponseEntry> l1 = new ArrayList<RegisterResponseEntry>();
    List<RegisterResponseEntry> l2 = new ArrayList<RegisterResponseEntry>();
    List<RegisterResponseEntry> l3 = new ArrayList<RegisterResponseEntry>();
    l1.add(new RegisterResponseEntry(1L, (short) 1, SOURCE1_SCHEMA_STR));
    l2.add(new RegisterResponseEntry(2L, (short) 1, SOURCE2_SCHEMA_STR));
    l3.add(new RegisterResponseEntry(3L, (short) 1, SOURCE3_SCHEMA_STR));
    schemaMap.put(1L, l1);
    schemaMap.put(2L, l2);
    schemaMap.put(3L, l3);
    // Enqueue Necessary messages before starting dispatch
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesIdsMessage(sourcesMap.values()));
    dispatcher.enqueueMessage(SourcesMessage.createSetSourcesSchemasMessage(schemaMap));
    log.info("starting event dispatch");
    // comm channels between reader and writer
    Pipe pipe = Pipe.open();
    Pipe.SinkChannel writerStream = pipe.sink();
    Pipe.SourceChannel readerStream = pipe.source();
    writerStream.configureBlocking(true);
    /*
       *  Needed for DbusEventBuffer.readEvents() to exit their loops when no more data is available.
       *  With Pipe mimicking ChunkedBodyReadableByteChannel, we need to make Pipe non-blocking on the
       *  reader side to achieve the behavior that ChunkedBodyReadableByte channel provides.
       */
    readerStream.configureBlocking(false);
    // Event writer - Relay in the real world
    Checkpoint cp = Checkpoint.createFlexibleCheckpoint();
    // Event readers - Clients in the real world
    // Checkpoint pullerCheckpoint = Checkpoint.createFlexibleCheckpoint();
    DbusEventsStatisticsCollector clientStats = new DbusEventsStatisticsCollector(0, "client", true, false, null);
    DbusEventBufferReader reader = new DbusEventBufferReader(destEventsBuf, readerStream, null, clientStats);
    UncaughtExceptionTrackingThread tReader = new UncaughtExceptionTrackingThread(reader, "Reader");
    tReader.setDaemon(true);
    tReader.start();
    try {
        log.info("send both windows");
        StreamEventsResult streamRes = srcEventsBuf.streamEvents(cp, writerStream, new StreamEventsArgs(win1Size));
        // EOP events, presumably?
        Assert.assertEquals(// EOP events, presumably?
        "num events streamed should equal total number of events plus 2", numEvents + 2, streamRes.getNumEventsStreamed());
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return 2 == mockConsumer.getNumBeginWindowCalls();
            }
        }, "second window processing started", 5000, log);
        dispatcher.shutdown();
        // remove the barrier
        mockConsumer.getLatch().countDown();
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return !dispatcherThread.isAlive();
            }
        }, "Ensure Dispatcher thread is shutdown", 5000, log);
        TestUtil.assertWithBackoff(new ConditionCheck() {

            @Override
            public boolean check() {
                return 0 == mockConsumer.getNumRollbacks();
            }
        }, "Ensure No Rollback is called", 10, log);
    } finally {
        reader.stop();
    }
    log.info("end\n");
}

Example 3 with StreamEventsResult

use of com.linkedin.databus.core.StreamEventsResult in project databus by linkedin.

the class ReadEventsRequestProcessor method process.

@Override
public DatabusRequest process(DatabusRequest request) throws IOException, RequestProcessingException, DatabusException {
    boolean isDebug = LOG.isDebugEnabled();
    try {
        ObjectMapper objMapper = new ObjectMapper();
        String checkpointString = request.getParams().getProperty(CHECKPOINT_PARAM, null);
        String checkpointStringMult = request.getParams().getProperty(CHECKPOINT_PARAM_MULT, null);
        int fetchSize = request.getRequiredIntParam(FETCH_SIZE_PARAM);
        String formatStr = request.getRequiredStringParam(OUTPUT_FORMAT_PARAM);
        Encoding enc = Encoding.valueOf(formatStr.toUpperCase());
        String sourcesListStr = request.getParams().getProperty(SOURCES_PARAM, null);
        String subsStr = request.getParams().getProperty(SUBS_PARAM, null);
        String partitionInfoStr = request.getParams().getProperty(PARTITION_INFO_STRING);
        String streamFromLatestSCNStr = request.getParams().getProperty(STREAM_FROM_LATEST_SCN);
        String clientMaxEventVersionStr = request.getParams().getProperty(DatabusHttpHeaders.MAX_EVENT_VERSION);
        int clientEventVersion = (clientMaxEventVersionStr != null) ? Integer.parseInt(clientMaxEventVersionStr) : DbusEventFactory.DBUS_EVENT_V1;
        if (clientEventVersion < 0 || clientEventVersion == 1 || clientEventVersion > DbusEventFactory.DBUS_EVENT_V2) {
            throw new InvalidRequestParamValueException(COMMAND_NAME, DatabusHttpHeaders.MAX_EVENT_VERSION, clientMaxEventVersionStr);
        }
        if (null == sourcesListStr && null == subsStr) {
            throw new InvalidRequestParamValueException(COMMAND_NAME, SOURCES_PARAM + "|" + SUBS_PARAM, "null");
        }
        // TODO for now we separte the code paths to limit the impact on existing Databus 2 deployments (DDSDBUS-79)
        // We have to get rid of this eventually and have a single data path.
        boolean v2Mode = null == subsStr;
        DbusKeyCompositeFilter keyCompositeFilter = null;
        if (null != partitionInfoStr) {
            try {
                Map<Long, DbusKeyFilter> fMap = KeyFilterConfigJSONFactory.parseSrcIdFilterConfigMap(partitionInfoStr);
                keyCompositeFilter = new DbusKeyCompositeFilter();
                keyCompositeFilter.setFilterMap(fMap);
                if (isDebug)
                    LOG.debug("keyCompositeFilter is :" + keyCompositeFilter);
            } catch (Exception ex) {
                String msg = "Got exception while parsing partition Configs. PartitionInfo is:" + partitionInfoStr;
                LOG.error(msg, ex);
                throw new InvalidRequestParamValueException(COMMAND_NAME, PARTITION_INFO_STRING, partitionInfoStr);
            }
        }
        boolean streamFromLatestSCN = false;
        if (null != streamFromLatestSCNStr) {
            streamFromLatestSCN = Boolean.valueOf(streamFromLatestSCNStr);
        }
        long start = System.currentTimeMillis();
        List<DatabusSubscription> subs = null;
        // parse source ids
        SourceIdNameRegistry srcRegistry = _relay.getSourcesIdNameRegistry();
        HashSet<Integer> sourceIds = new HashSet<Integer>();
        if (null != sourcesListStr) {
            String[] sourcesList = sourcesListStr.split(",");
            for (String sourceId : sourcesList) {
                try {
                    Integer srcId = Integer.valueOf(sourceId);
                    sourceIds.add(srcId);
                } catch (NumberFormatException nfe) {
                    HttpStatisticsCollector globalHttpStatsCollector = _relay.getHttpStatisticsCollector();
                    if (null != globalHttpStatsCollector) {
                        globalHttpStatsCollector.registerInvalidStreamRequest();
                    }
                    throw new InvalidRequestParamValueException(COMMAND_NAME, SOURCES_PARAM, sourceId);
                }
            }
        }
        // process explicit subscriptions and generate respective logical partition filters
        NavigableSet<PhysicalPartitionKey> ppartKeys = null;
        if (null != subsStr) {
            List<DatabusSubscription.Builder> subsBuilder = null;
            subsBuilder = objMapper.readValue(subsStr, new TypeReference<List<DatabusSubscription.Builder>>() {
            });
            subs = new ArrayList<DatabusSubscription>(subsBuilder.size());
            for (DatabusSubscription.Builder subBuilder : subsBuilder) {
                subs.add(subBuilder.build());
            }
            ppartKeys = new TreeSet<PhysicalPartitionKey>();
            for (DatabusSubscription sub : subs) {
                PhysicalPartition ppart = sub.getPhysicalPartition();
                if (ppart.isAnyPartitionWildcard()) {
                    ppartKeys = _eventBuffer.getAllPhysicalPartitionKeys();
                    break;
                } else {
                    ppartKeys.add(new PhysicalPartitionKey(ppart));
                }
            }
        }
        // Need to make sure that we don't have tests that send requests in this form.
        if (subs != null && checkpointStringMult == null && checkpointString != null) {
            throw new RequestProcessingException("Both Subscriptions and CheckpointMult should be present");
        }
        // convert source ids into subscriptions
        if (null == subs)
            subs = new ArrayList<DatabusSubscription>();
        for (Integer srcId : sourceIds) {
            LogicalSource lsource = srcRegistry.getSource(srcId);
            if (lsource == null)
                throw new InvalidRequestParamValueException(COMMAND_NAME, SOURCES_PARAM, srcId.toString());
            if (isDebug)
                LOG.debug("registry returns " + lsource + " for srcid=" + srcId);
            DatabusSubscription newSub = DatabusSubscription.createSimpleSourceSubscription(lsource);
            subs.add(newSub);
        }
        DbusFilter ppartFilters = null;
        if (subs.size() > 0) {
            try {
                ppartFilters = _eventBuffer.constructFilters(subs);
            } catch (DatabusException de) {
                throw new RequestProcessingException("unable to generate physical partitions filters:" + de.getMessage(), de);
            }
        }
        ConjunctionDbusFilter filters = new ConjunctionDbusFilter();
        // Source filter comes first
        if (v2Mode)
            filters.addFilter(new SourceDbusFilter(sourceIds));
        else if (null != ppartFilters)
            filters.addFilter(ppartFilters);
        /*
      // Key range filter comes next
      if ((keyMin >0) && (keyMax > 0))
      {
        filters.addFilter(new KeyRangeFilter(keyMin, keyMax));
      }
      */
        if (null != keyCompositeFilter) {
            filters.addFilter(keyCompositeFilter);
        }
        // need to update registerStreamRequest to support Mult checkpoint TODO (DDSDBUS-80)
        // temp solution
        // 3 options:
        // 1. checkpointStringMult not null - generate checkpoint from it
        // 2. checkpointStringMult null, checkpointString not null - create empty CheckpointMult
        // and add create Checkpoint(checkpointString) and add it to cpMult;
        // 3 both are null - create empty CheckpointMult and add empty Checkpoint to it for each ppartition
        PhysicalPartition pPartition;
        Checkpoint cp = null;
        CheckpointMult cpMult = null;
        if (checkpointStringMult != null) {
            try {
                cpMult = new CheckpointMult(checkpointStringMult);
            } catch (InvalidParameterSpecException e) {
                LOG.error("Invalid CheckpointMult:" + checkpointStringMult, e);
                throw new InvalidRequestParamValueException("stream", "CheckpointMult", checkpointStringMult);
            }
        } else {
            // there is no checkpoint - create an empty one
            cpMult = new CheckpointMult();
            Iterator<Integer> it = sourceIds.iterator();
            while (it.hasNext()) {
                Integer srcId = it.next();
                pPartition = _eventBuffer.getPhysicalPartition(srcId);
                if (pPartition == null)
                    throw new RequestProcessingException("unable to find physical partitions for source:" + srcId);
                if (checkpointString != null) {
                    cp = new Checkpoint(checkpointString);
                } else {
                    cp = new Checkpoint();
                    cp.setFlexible();
                }
                cpMult.addCheckpoint(pPartition, cp);
            }
        }
        if (isDebug)
            LOG.debug("checkpointStringMult = " + checkpointStringMult + ";singlecheckpointString=" + checkpointString + ";CPM=" + cpMult);
        // of the server context.
        if (cpMult.getCursorPartition() == null) {
            cpMult.setCursorPartition(request.getCursorPartition());
        }
        if (isDebug) {
            if (cpMult.getCursorPartition() != null) {
                LOG.debug("Using physical paritition cursor " + cpMult.getCursorPartition());
            }
        }
        // for registerStreamRequest we need a single Checkpoint (TODO - fix it) (DDSDBUS-81)
        if (cp == null) {
            Iterator<Integer> it = sourceIds.iterator();
            if (it.hasNext()) {
                Integer srcId = it.next();
                pPartition = _eventBuffer.getPhysicalPartition(srcId);
                cp = cpMult.getCheckpoint(pPartition);
            } else {
                cp = new Checkpoint();
                cp.setFlexible();
            }
        }
        if (null != checkpointString && isDebug)
            LOG.debug("About to stream from cp: " + checkpointString.toString());
        HttpStatisticsCollector globalHttpStatsCollector = _relay.getHttpStatisticsCollector();
        HttpStatisticsCollector connHttpStatsCollector = null;
        if (null != globalHttpStatsCollector) {
            connHttpStatsCollector = (HttpStatisticsCollector) request.getParams().get(globalHttpStatsCollector.getName());
        }
        if (null != globalHttpStatsCollector)
            globalHttpStatsCollector.registerStreamRequest(cp, sourceIds);
        StatsCollectors<DbusEventsStatisticsCollector> statsCollectors = _relay.getOutBoundStatsCollectors();
        try {
            DbusEventBufferBatchReadable bufRead = v2Mode ? _eventBuffer.getDbusEventBufferBatchReadable(sourceIds, cpMult, statsCollectors) : _eventBuffer.getDbusEventBufferBatchReadable(cpMult, ppartKeys, statsCollectors);
            int eventsRead = 0;
            int minPendingEventSize = 0;
            StreamEventsResult result = null;
            bufRead.setClientMaxEventVersion(clientEventVersion);
            if (v2Mode) {
                result = bufRead.streamEvents(streamFromLatestSCN, fetchSize, request.getResponseContent(), enc, filters);
                eventsRead = result.getNumEventsStreamed();
                minPendingEventSize = result.getSizeOfPendingEvent();
                if (isDebug) {
                    LOG.debug("Process: streamed " + eventsRead + " from sources " + Arrays.toString(sourceIds.toArray()));
                    // can be used for debugging to stream from a cp
                    LOG.debug("CP=" + cpMult);
                }
            // if (null != statsCollectors) statsCollectors.mergeStatsCollectors();
            } else {
                result = bufRead.streamEvents(streamFromLatestSCN, fetchSize, request.getResponseContent(), enc, filters);
                eventsRead = result.getNumEventsStreamed();
                minPendingEventSize = result.getSizeOfPendingEvent();
                if (isDebug)
                    LOG.debug("Process: streamed " + eventsRead + " with subscriptions " + subs);
                cpMult = bufRead.getCheckpointMult();
                if (cpMult != null) {
                    request.setCursorPartition(cpMult.getCursorPartition());
                }
            }
            if (eventsRead == 0 && minPendingEventSize > 0) {
                // Append a header to indicate to the client that we do have at least one event to
                // send, but it is too large to fit into client's offered buffer.
                request.getResponseContent().addMetadata(DatabusHttpHeaders.DATABUS_PENDING_EVENT_SIZE, minPendingEventSize);
                LOG.debug("Returning 0 events but have pending event of size " + minPendingEventSize);
            }
        } catch (ScnNotFoundException snfe) {
            if (null != globalHttpStatsCollector) {
                globalHttpStatsCollector.registerScnNotFoundStreamResponse();
            }
            throw new RequestProcessingException(snfe);
        } catch (OffsetNotFoundException snfe) {
            LOG.error("OffsetNotFound", snfe);
            if (null != globalHttpStatsCollector) {
                globalHttpStatsCollector.registerScnNotFoundStreamResponse();
            }
            throw new RequestProcessingException(snfe);
        }
        if (null != connHttpStatsCollector) {
            connHttpStatsCollector.registerStreamResponse(System.currentTimeMillis() - start);
            globalHttpStatsCollector.merge(connHttpStatsCollector);
            connHttpStatsCollector.reset();
        } else if (null != globalHttpStatsCollector) {
            globalHttpStatsCollector.registerStreamResponse(System.currentTimeMillis() - start);
        }
    } catch (InvalidRequestParamValueException e) {
        HttpStatisticsCollector globalHttpStatsCollector = _relay.getHttpStatisticsCollector();
        if (null != globalHttpStatsCollector) {
            globalHttpStatsCollector.registerInvalidStreamRequest();
        }
        throw e;
    }
    return request;
}