Examples with TxnHeader org.apache.zookeeper.txn.TxnHeader used on opensource projects

Example 11 with TxnHeader

use of org.apache.zookeeper.txn.TxnHeader in project zookeeper by apache.

the class FinalRequestProcessor method processRequest.

public void processRequest(Request request) {
    if (LOG.isDebugEnabled()) {
        LOG.debug("Processing request:: " + request);
    }
    // request.addRQRec(">final");
    long traceMask = ZooTrace.CLIENT_REQUEST_TRACE_MASK;
    if (request.type == OpCode.ping) {
        traceMask = ZooTrace.SERVER_PING_TRACE_MASK;
    }
    if (LOG.isTraceEnabled()) {
        ZooTrace.logRequest(LOG, traceMask, 'E', request, "");
    }
    ProcessTxnResult rc = null;
    synchronized (zks.outstandingChanges) {
        // Need to process local session requests
        rc = zks.processTxn(request);
        // that add to outstandingChanges.
        if (request.getHdr() != null) {
            TxnHeader hdr = request.getHdr();
            Record txn = request.getTxn();
            long zxid = hdr.getZxid();
            while (!zks.outstandingChanges.isEmpty() && zks.outstandingChanges.get(0).zxid <= zxid) {
                ChangeRecord cr = zks.outstandingChanges.remove(0);
                if (cr.zxid < zxid) {
                    LOG.warn("Zxid outstanding " + cr.zxid + " is less than current " + zxid);
                }
                if (zks.outstandingChangesForPath.get(cr.path) == cr) {
                    zks.outstandingChangesForPath.remove(cr.path);
                }
            }
        }
        // do not add non quorum packets to the queue.
        if (request.isQuorum()) {
            zks.getZKDatabase().addCommittedProposal(request);
        }
    }
    // Calling closeSession() after losing the cnxn, results in the client close session response being dropped.
    if (request.type == OpCode.closeSession && connClosedByClient(request)) {
        // we are just playing diffs from the leader.
        if (closeSession(zks.serverCnxnFactory, request.sessionId) || closeSession(zks.secureServerCnxnFactory, request.sessionId)) {
            return;
        }
    }
    if (request.cnxn == null) {
        return;
    }
    ServerCnxn cnxn = request.cnxn;
    String lastOp = "NA";
    zks.decInProcess();
    Code err = Code.OK;
    Record rsp = null;
    try {
        if (request.getHdr() != null && request.getHdr().getType() == OpCode.error) {
            /*
                 * When local session upgrading is disabled, leader will
                 * reject the ephemeral node creation due to session expire.
                 * However, if this is the follower that issue the request,
                 * it will have the correct error code, so we should use that
                 * and report to user
                 */
            if (request.getException() != null) {
                throw request.getException();
            } else {
                throw KeeperException.create(KeeperException.Code.get(((ErrorTxn) request.getTxn()).getErr()));
            }
        }
        KeeperException ke = request.getException();
        if (ke != null && request.type != OpCode.multi) {
            throw ke;
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("{}", request);
        }
        switch(request.type) {
            case OpCode.ping:
                {
                    zks.serverStats().updateLatency(request.createTime);
                    lastOp = "PING";
                    cnxn.updateStatsForResponse(request.cxid, request.zxid, lastOp, request.createTime, Time.currentElapsedTime());
                    cnxn.sendResponse(new ReplyHeader(-2, zks.getZKDatabase().getDataTreeLastProcessedZxid(), 0), null, "response");
                    return;
                }
            case OpCode.createSession:
                {
                    zks.serverStats().updateLatency(request.createTime);
                    lastOp = "SESS";
                    cnxn.updateStatsForResponse(request.cxid, request.zxid, lastOp, request.createTime, Time.currentElapsedTime());
                    zks.finishSessionInit(request.cnxn, true);
                    return;
                }
            case OpCode.multi:
                {
                    lastOp = "MULT";
                    rsp = new MultiResponse();
                    for (ProcessTxnResult subTxnResult : rc.multiResult) {
                        OpResult subResult;
                        switch(subTxnResult.type) {
                            case OpCode.check:
                                subResult = new CheckResult();
                                break;
                            case OpCode.create:
                                subResult = new CreateResult(subTxnResult.path);
                                break;
                            case OpCode.create2:
                            case OpCode.createTTL:
                            case OpCode.createContainer:
                                subResult = new CreateResult(subTxnResult.path, subTxnResult.stat);
                                break;
                            case OpCode.delete:
                            case OpCode.deleteContainer:
                                subResult = new DeleteResult();
                                break;
                            case OpCode.setData:
                                subResult = new SetDataResult(subTxnResult.stat);
                                break;
                            case OpCode.error:
                                subResult = new ErrorResult(subTxnResult.err);
                                break;
                            default:
                                throw new IOException("Invalid type of op");
                        }
                        ((MultiResponse) rsp).add(subResult);
                    }
                    break;
                }
            case OpCode.create:
                {
                    lastOp = "CREA";
                    rsp = new CreateResponse(rc.path);
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.create2:
            case OpCode.createTTL:
            case OpCode.createContainer:
                {
                    lastOp = "CREA";
                    rsp = new Create2Response(rc.path, rc.stat);
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.delete:
            case OpCode.deleteContainer:
                {
                    lastOp = "DELE";
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.setData:
                {
                    lastOp = "SETD";
                    rsp = new SetDataResponse(rc.stat);
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.reconfig:
                {
                    lastOp = "RECO";
                    rsp = new GetDataResponse(((QuorumZooKeeperServer) zks).self.getQuorumVerifier().toString().getBytes(), rc.stat);
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.setACL:
                {
                    lastOp = "SETA";
                    rsp = new SetACLResponse(rc.stat);
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.closeSession:
                {
                    lastOp = "CLOS";
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.sync:
                {
                    lastOp = "SYNC";
                    SyncRequest syncRequest = new SyncRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, syncRequest);
                    rsp = new SyncResponse(syncRequest.getPath());
                    break;
                }
            case OpCode.check:
                {
                    lastOp = "CHEC";
                    rsp = new SetDataResponse(rc.stat);
                    err = Code.get(rc.err);
                    break;
                }
            case OpCode.exists:
                {
                    lastOp = "EXIS";
                    // TODO we need to figure out the security requirement for this!
                    ExistsRequest existsRequest = new ExistsRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, existsRequest);
                    String path = existsRequest.getPath();
                    if (path.indexOf('\0') != -1) {
                        throw new KeeperException.BadArgumentsException();
                    }
                    Stat stat = zks.getZKDatabase().statNode(path, existsRequest.getWatch() ? cnxn : null);
                    rsp = new ExistsResponse(stat);
                    break;
                }
            case OpCode.getData:
                {
                    lastOp = "GETD";
                    GetDataRequest getDataRequest = new GetDataRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, getDataRequest);
                    DataNode n = zks.getZKDatabase().getNode(getDataRequest.getPath());
                    if (n == null) {
                        throw new KeeperException.NoNodeException();
                    }
                    PrepRequestProcessor.checkACL(zks, request.cnxn, zks.getZKDatabase().aclForNode(n), ZooDefs.Perms.READ, request.authInfo, getDataRequest.getPath(), null);
                    Stat stat = new Stat();
                    byte[] b = zks.getZKDatabase().getData(getDataRequest.getPath(), stat, getDataRequest.getWatch() ? cnxn : null);
                    rsp = new GetDataResponse(b, stat);
                    break;
                }
            case OpCode.setWatches:
                {
                    lastOp = "SETW";
                    SetWatches setWatches = new SetWatches();
                    // XXX We really should NOT need this!!!!
                    request.request.rewind();
                    ByteBufferInputStream.byteBuffer2Record(request.request, setWatches);
                    long relativeZxid = setWatches.getRelativeZxid();
                    zks.getZKDatabase().setWatches(relativeZxid, setWatches.getDataWatches(), setWatches.getExistWatches(), setWatches.getChildWatches(), cnxn);
                    break;
                }
            case OpCode.getACL:
                {
                    lastOp = "GETA";
                    GetACLRequest getACLRequest = new GetACLRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, getACLRequest);
                    Stat stat = new Stat();
                    List<ACL> acl = zks.getZKDatabase().getACL(getACLRequest.getPath(), stat);
                    rsp = new GetACLResponse(acl, stat);
                    break;
                }
            case OpCode.getChildren:
                {
                    lastOp = "GETC";
                    GetChildrenRequest getChildrenRequest = new GetChildrenRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, getChildrenRequest);
                    DataNode n = zks.getZKDatabase().getNode(getChildrenRequest.getPath());
                    if (n == null) {
                        throw new KeeperException.NoNodeException();
                    }
                    PrepRequestProcessor.checkACL(zks, request.cnxn, zks.getZKDatabase().aclForNode(n), ZooDefs.Perms.READ, request.authInfo, getChildrenRequest.getPath(), null);
                    List<String> children = zks.getZKDatabase().getChildren(getChildrenRequest.getPath(), null, getChildrenRequest.getWatch() ? cnxn : null);
                    rsp = new GetChildrenResponse(children);
                    break;
                }
            case OpCode.getChildren2:
                {
                    lastOp = "GETC";
                    GetChildren2Request getChildren2Request = new GetChildren2Request();
                    ByteBufferInputStream.byteBuffer2Record(request.request, getChildren2Request);
                    Stat stat = new Stat();
                    DataNode n = zks.getZKDatabase().getNode(getChildren2Request.getPath());
                    if (n == null) {
                        throw new KeeperException.NoNodeException();
                    }
                    PrepRequestProcessor.checkACL(zks, request.cnxn, zks.getZKDatabase().aclForNode(n), ZooDefs.Perms.READ, request.authInfo, getChildren2Request.getPath(), null);
                    List<String> children = zks.getZKDatabase().getChildren(getChildren2Request.getPath(), stat, getChildren2Request.getWatch() ? cnxn : null);
                    rsp = new GetChildren2Response(children, stat);
                    break;
                }
            case OpCode.checkWatches:
                {
                    lastOp = "CHKW";
                    CheckWatchesRequest checkWatches = new CheckWatchesRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, checkWatches);
                    WatcherType type = WatcherType.fromInt(checkWatches.getType());
                    boolean containsWatcher = zks.getZKDatabase().containsWatcher(checkWatches.getPath(), type, cnxn);
                    if (!containsWatcher) {
                        String msg = String.format(Locale.ENGLISH, "%s (type: %s)", new Object[] { checkWatches.getPath(), type });
                        throw new KeeperException.NoWatcherException(msg);
                    }
                    break;
                }
            case OpCode.removeWatches:
                {
                    lastOp = "REMW";
                    RemoveWatchesRequest removeWatches = new RemoveWatchesRequest();
                    ByteBufferInputStream.byteBuffer2Record(request.request, removeWatches);
                    WatcherType type = WatcherType.fromInt(removeWatches.getType());
                    boolean removed = zks.getZKDatabase().removeWatch(removeWatches.getPath(), type, cnxn);
                    if (!removed) {
                        String msg = String.format(Locale.ENGLISH, "%s (type: %s)", new Object[] { removeWatches.getPath(), type });
                        throw new KeeperException.NoWatcherException(msg);
                    }
                    break;
                }
        }
    } catch (SessionMovedException e) {
        // session moved is a connection level error, we need to tear
        // down the connection otw ZOOKEEPER-710 might happen
        // ie client on slow follower starts to renew session, fails
        // before this completes, then tries the fast follower (leader)
        // and is successful, however the initial renew is then
        // successfully fwd/processed by the leader and as a result
        // the client and leader disagree on where the client is most
        // recently attached (and therefore invalid SESSION MOVED generated)
        cnxn.sendCloseSession();
        return;
    } catch (KeeperException e) {
        err = e.code();
    } catch (Exception e) {
        // log at error level as we are returning a marshalling
        // error to the user
        LOG.error("Failed to process " + request, e);
        StringBuilder sb = new StringBuilder();
        ByteBuffer bb = request.request;
        bb.rewind();
        while (bb.hasRemaining()) {
            sb.append(Integer.toHexString(bb.get() & 0xff));
        }
        LOG.error("Dumping request buffer: 0x" + sb.toString());
        err = Code.MARSHALLINGERROR;
    }
    long lastZxid = zks.getZKDatabase().getDataTreeLastProcessedZxid();
    ReplyHeader hdr = new ReplyHeader(request.cxid, lastZxid, err.intValue());
    zks.serverStats().updateLatency(request.createTime);
    cnxn.updateStatsForResponse(request.cxid, lastZxid, lastOp, request.createTime, Time.currentElapsedTime());
    try {
        cnxn.sendResponse(hdr, rsp, "response");
        if (request.type == OpCode.closeSession) {
            cnxn.sendCloseSession();
        }
    } catch (IOException e) {
        LOG.error("FIXMSG", e);
    }
}

Example 12 with TxnHeader

use of org.apache.zookeeper.txn.TxnHeader in project zookeeper by apache.

the class LogFormatter method main.

/**
     * @param args
     */
public static void main(String[] args) throws Exception {
    if (args.length != 1) {
        System.err.println("USAGE: LogFormatter log_file");
        System.exit(2);
    }
    FileInputStream fis = new FileInputStream(args[0]);
    BinaryInputArchive logStream = BinaryInputArchive.getArchive(fis);
    FileHeader fhdr = new FileHeader();
    fhdr.deserialize(logStream, "fileheader");
    if (fhdr.getMagic() != FileTxnLog.TXNLOG_MAGIC) {
        System.err.println("Invalid magic number for " + args[0]);
        System.exit(2);
    }
    System.out.println("ZooKeeper Transactional Log File with dbid " + fhdr.getDbid() + " txnlog format version " + fhdr.getVersion());
    int count = 0;
    while (true) {
        long crcValue;
        byte[] bytes;
        try {
            crcValue = logStream.readLong("crcvalue");
            bytes = logStream.readBuffer("txnEntry");
        } catch (EOFException e) {
            System.out.println("EOF reached after " + count + " txns.");
            return;
        }
        if (bytes.length == 0) {
            // Since we preallocate, we define EOF to be an
            // empty transaction
            System.out.println("EOF reached after " + count + " txns.");
            return;
        }
        Checksum crc = new Adler32();
        crc.update(bytes, 0, bytes.length);
        if (crcValue != crc.getValue()) {
            throw new IOException("CRC doesn't match " + crcValue + " vs " + crc.getValue());
        }
        TxnHeader hdr = new TxnHeader();
        Record txn = SerializeUtils.deserializeTxn(bytes, hdr);
        System.out.println(DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.LONG).format(new Date(hdr.getTime())) + " session 0x" + Long.toHexString(hdr.getClientId()) + " cxid 0x" + Long.toHexString(hdr.getCxid()) + " zxid 0x" + Long.toHexString(hdr.getZxid()) + " " + TraceFormatter.op2String(hdr.getType()) + " " + txn);
        if (logStream.readByte("EOR") != 'B') {
            LOG.error("Last transaction was partial.");
            throw new EOFException("Last transaction was partial.");
        }
        count++;
    }
}

Example 13 with TxnHeader

use of org.apache.zookeeper.txn.TxnHeader in project zookeeper by apache.

the class GetProposalFromTxnTest method testGetProposalFromTxn.

/**
     * Test loading proposal from txnlog
     *
     * @throws Exception
     *             an exception might be thrown here
     */
@Test
public void testGetProposalFromTxn() throws Exception {
    File tmpDir = ClientBase.createTmpDir();
    ClientBase.setupTestEnv();
    ZooKeeperServer zks = new ZooKeeperServer(tmpDir, tmpDir, 3000);
    SyncRequestProcessor.setSnapCount(100);
    final int PORT = Integer.parseInt(HOSTPORT.split(":")[1]);
    ServerCnxnFactory f = ServerCnxnFactory.createFactory(PORT, -1);
    f.startup(zks);
    Assert.assertTrue("waiting for server being up ", ClientBase.waitForServerUp(HOSTPORT, CONNECTION_TIMEOUT));
    ZooKeeper zk = ClientBase.createZKClient(HOSTPORT);
    // Generate transaction so we will have some txnlog
    Long[] zxids = new Long[MSG_COUNT];
    try {
        String data = "data";
        byte[] bytes = data.getBytes();
        for (int i = 0; i < MSG_COUNT; i++) {
            Stat stat = new Stat();
            zk.create("/invalidsnap-" + i, bytes, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            zk.getData("/invalidsnap-" + i, null, stat);
            zxids[i] = stat.getCzxid();
        }
    } finally {
        zk.close();
    }
    // shutdown and start zookeeper again
    f.shutdown();
    zks.shutdown();
    Assert.assertTrue("waiting for server to shutdown", ClientBase.waitForServerDown(HOSTPORT, CONNECTION_TIMEOUT));
    zks = new ZooKeeperServer(tmpDir, tmpDir, 3000);
    zks.startdata();
    ZKDatabase db = zks.getZKDatabase();
    // Set sizeLimit to be very high number, so we can pull all transactions
    // from txnlog
    Iterator<Proposal> itr = db.getProposalsFromTxnLog(zxids[0], 10000000);
    int createCount = 0;
    ArrayList<Long> retrievedZxids = new ArrayList<Long>(MSG_COUNT);
    // Get zxid of create requests
    while (itr.hasNext()) {
        Proposal proposal = itr.next();
        TxnHeader hdr = new TxnHeader();
        Record rec = SerializeUtils.deserializeTxn(proposal.packet.getData(), hdr);
        if (hdr.getType() == OpCode.create) {
            retrievedZxids.add(hdr.getZxid());
            createCount++;
        }
    }
    // All zxid should match what we created
    Assert.assertTrue("Zxids missmatches", Arrays.equals(zxids, retrievedZxids.toArray(new Long[0])));
    // There should be 2000 create requests
    Assert.assertTrue("create proposal count == " + MSG_COUNT, (createCount == MSG_COUNT));
    // We are requesting half the number of transaction from the snapshot
    // this should exceed threshold (ZKDatabase.snapshotSizeFactor)
    db.setSnapshotSizeFactor(0.33);
    long sizeLimit = db.calculateTxnLogSizeLimit();
    itr = db.getProposalsFromTxnLog(zxids[MSG_COUNT / 2], sizeLimit);
    Assert.assertFalse("Expect empty proposal", (itr.hasNext()));
    f.shutdown();
    zks.shutdown();
}

Example 14 with TxnHeader

use of org.apache.zookeeper.txn.TxnHeader in project zookeeper by apache.

the class LoadFromLogTest method doOp.

/*
     * Does create/delete depending on the type and verifies
     * if cversion before the operation is 1 less than cversion afer.
     */
private void doOp(FileTxnSnapLog logFile, int type, String path, DataTree dt, DataNode parent, int cversion) throws Exception {
    int lastSlash = path.lastIndexOf('/');
    String parentName = path.substring(0, lastSlash);
    int prevCversion = parent.stat.getCversion();
    long prevPzxid = parent.stat.getPzxid();
    List<String> child = dt.getChildren(parentName, null, null);
    StringBuilder childStr = new StringBuilder();
    for (String s : child) {
        childStr.append(s).append(" ");
    }
    LOG.info("Children: " + childStr + " for " + parentName);
    LOG.info("(cverions, pzxid): " + prevCversion + ", " + prevPzxid);
    Record txn = null;
    TxnHeader txnHeader = null;
    if (type == OpCode.delete) {
        txn = new DeleteTxn(path);
        txnHeader = new TxnHeader(0xabcd, 0x123, prevPzxid + 1, Time.currentElapsedTime(), OpCode.delete);
    } else if (type == OpCode.create) {
        txnHeader = new TxnHeader(0xabcd, 0x123, prevPzxid + 1, Time.currentElapsedTime(), OpCode.create);
        txn = new CreateTxn(path, new byte[0], null, false, cversion);
    } else if (type == OpCode.multi) {
        txnHeader = new TxnHeader(0xabcd, 0x123, prevPzxid + 1, Time.currentElapsedTime(), OpCode.create);
        txn = new CreateTxn(path, new byte[0], null, false, cversion);
        List<Txn> txnList = new ArrayList<Txn>();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        BinaryOutputArchive boa = BinaryOutputArchive.getArchive(baos);
        txn.serialize(boa, "request");
        ByteBuffer bb = ByteBuffer.wrap(baos.toByteArray());
        Txn txact = new Txn(OpCode.create, bb.array());
        txnList.add(txact);
        txn = new MultiTxn(txnList);
        txnHeader = new TxnHeader(0xabcd, 0x123, prevPzxid + 1, Time.currentElapsedTime(), OpCode.multi);
    }
    logFile.processTransaction(txnHeader, dt, null, txn);
    int newCversion = parent.stat.getCversion();
    long newPzxid = parent.stat.getPzxid();
    child = dt.getChildren(parentName, null, null);
    childStr = new StringBuilder();
    for (String s : child) {
        childStr.append(s).append(" ");
    }
    LOG.info("Children: " + childStr + " for " + parentName);
    LOG.info("(cverions, pzxid): " + newCversion + ", " + newPzxid);
    Assert.assertTrue(type + " <cversion, pzxid> verification failed. Expected: <" + (prevCversion + 1) + ", " + (prevPzxid + 1) + ">, found: <" + newCversion + ", " + newPzxid + ">", (newCversion == prevCversion + 1 && newPzxid == prevPzxid + 1));
}

Example 15 with TxnHeader

use of org.apache.zookeeper.txn.TxnHeader in project zookeeper by apache.

the class PrepRequestProcessor method pRequest.

/**
     * This method will be called inside the ProcessRequestThread, which is a
     * singleton, so there will be a single thread calling this code.
     *
     * @param request
     */
protected void pRequest(Request request) throws RequestProcessorException {
    // LOG.info("Prep>>> cxid = " + request.cxid + " type = " +
    // request.type + " id = 0x" + Long.toHexString(request.sessionId));
    request.setHdr(null);
    request.setTxn(null);
    try {
        switch(request.type) {
            case OpCode.createContainer:
            case OpCode.create:
            case OpCode.create2:
                CreateRequest create2Request = new CreateRequest();
                pRequest2Txn(request.type, zks.getNextZxid(), request, create2Request, true);
                break;
            case OpCode.createTTL:
                CreateTTLRequest createTtlRequest = new CreateTTLRequest();
                pRequest2Txn(request.type, zks.getNextZxid(), request, createTtlRequest, true);
                break;
            case OpCode.deleteContainer:
            case OpCode.delete:
                DeleteRequest deleteRequest = new DeleteRequest();
                pRequest2Txn(request.type, zks.getNextZxid(), request, deleteRequest, true);
                break;
            case OpCode.setData:
                SetDataRequest setDataRequest = new SetDataRequest();
                pRequest2Txn(request.type, zks.getNextZxid(), request, setDataRequest, true);
                break;
            case OpCode.reconfig:
                ReconfigRequest reconfigRequest = new ReconfigRequest();
                ByteBufferInputStream.byteBuffer2Record(request.request, reconfigRequest);
                pRequest2Txn(request.type, zks.getNextZxid(), request, reconfigRequest, true);
                break;
            case OpCode.setACL:
                SetACLRequest setAclRequest = new SetACLRequest();
                pRequest2Txn(request.type, zks.getNextZxid(), request, setAclRequest, true);
                break;
            case OpCode.check:
                CheckVersionRequest checkRequest = new CheckVersionRequest();
                pRequest2Txn(request.type, zks.getNextZxid(), request, checkRequest, true);
                break;
            case OpCode.multi:
                MultiTransactionRecord multiRequest = new MultiTransactionRecord();
                try {
                    ByteBufferInputStream.byteBuffer2Record(request.request, multiRequest);
                } catch (IOException e) {
                    request.setHdr(new TxnHeader(request.sessionId, request.cxid, zks.getNextZxid(), Time.currentWallTime(), OpCode.multi));
                    throw e;
                }
                List<Txn> txns = new ArrayList<Txn>();
                //Each op in a multi-op must have the same zxid!
                long zxid = zks.getNextZxid();
                KeeperException ke = null;
                //Store off current pending change records in case we need to rollback
                Map<String, ChangeRecord> pendingChanges = getPendingChanges(multiRequest);
                for (Op op : multiRequest) {
                    Record subrequest = op.toRequestRecord();
                    int type;
                    Record txn;
                    /* If we've already failed one of the ops, don't bother
                     * trying the rest as we know it's going to fail and it
                     * would be confusing in the logfiles.
                     */
                    if (ke != null) {
                        type = OpCode.error;
                        txn = new ErrorTxn(Code.RUNTIMEINCONSISTENCY.intValue());
                    } else /* Prep the request and convert to a Txn */
                    {
                        try {
                            pRequest2Txn(op.getType(), zxid, request, subrequest, false);
                            type = request.getHdr().getType();
                            txn = request.getTxn();
                        } catch (KeeperException e) {
                            ke = e;
                            type = OpCode.error;
                            txn = new ErrorTxn(e.code().intValue());
                            LOG.info("Got user-level KeeperException when processing " + request.toString() + " aborting remaining multi ops." + " Error Path:" + e.getPath() + " Error:" + e.getMessage());
                            request.setException(e);
                            /* Rollback change records from failed multi-op */
                            rollbackPendingChanges(zxid, pendingChanges);
                        }
                    }
                    //FIXME: I don't want to have to serialize it here and then
                    //       immediately deserialize in next processor. But I'm
                    //       not sure how else to get the txn stored into our list.
                    ByteArrayOutputStream baos = new ByteArrayOutputStream();
                    BinaryOutputArchive boa = BinaryOutputArchive.getArchive(baos);
                    txn.serialize(boa, "request");
                    ByteBuffer bb = ByteBuffer.wrap(baos.toByteArray());
                    txns.add(new Txn(type, bb.array()));
                }
                request.setHdr(new TxnHeader(request.sessionId, request.cxid, zxid, Time.currentWallTime(), request.type));
                request.setTxn(new MultiTxn(txns));
                break;
            //create/close session don't require request record
            case OpCode.createSession:
            case OpCode.closeSession:
                if (!request.isLocalSession()) {
                    pRequest2Txn(request.type, zks.getNextZxid(), request, null, true);
                }
                break;
            //All the rest don't need to create a Txn - just verify session
            case OpCode.sync:
            case OpCode.exists:
            case OpCode.getData:
            case OpCode.getACL:
            case OpCode.getChildren:
            case OpCode.getChildren2:
            case OpCode.ping:
            case OpCode.setWatches:
            case OpCode.checkWatches:
            case OpCode.removeWatches:
                zks.sessionTracker.checkSession(request.sessionId, request.getOwner());
                break;
            default:
                LOG.warn("unknown type " + request.type);
                break;
        }
    } catch (KeeperException e) {
        if (request.getHdr() != null) {
            request.getHdr().setType(OpCode.error);
            request.setTxn(new ErrorTxn(e.code().intValue()));
        }
        LOG.info("Got user-level KeeperException when processing " + request.toString() + " Error Path:" + e.getPath() + " Error:" + e.getMessage());
        request.setException(e);
    } catch (Exception e) {
        // log at error level as we are returning a marshalling
        // error to the user
        LOG.error("Failed to process " + request, e);
        StringBuilder sb = new StringBuilder();
        ByteBuffer bb = request.request;
        if (bb != null) {
            bb.rewind();
            while (bb.hasRemaining()) {
                sb.append(Integer.toHexString(bb.get() & 0xff));
            }
        } else {
            sb.append("request buffer is null");
        }
        LOG.error("Dumping request buffer: 0x" + sb.toString());
        if (request.getHdr() != null) {
            request.getHdr().setType(OpCode.error);
            request.setTxn(new ErrorTxn(Code.MARSHALLINGERROR.intValue()));
        }
    }
    request.zxid = zks.getZxid();
    nextProcessor.processRequest(request);
}