About non-blocking Interaction mode
I would like to know when the Forms runtime will display a dialog that allows the user to cancel the query after I have set a form in non-blocking Interaction mode.
In a time-consuming query, the dialog must appear after
few seconds or its depend on other condition?
And, what is time-consuming query?
Thank you
it will appear in the 5 seconds with a dialog 'press Cancel button to change this database session' 5 times after you press the button.
To mimick, you set 'query all' to 'yes', then you will see it.
As of what is timimg-consuming, it depends on your app. performance requirment.
Similar Messages
-
UTL_TCP (blocking or non-blocking sockets mode)
Hi for All,
Please, someone knows if the UTL_TCP using blocking or non-blocking sockets mode? I did a search but can not find this information.
Regards,Blocking only occurs when you attempt to read from the socket and there's no data to read. (in which case, the time out setting applies if specified)
This is however not that robust in my experience. UTL_TCP provides a peek method (returns byte size of socket buffer) that tells you whether or not there is data for that socket. This enables you to verify that you read on that socket will not be a blocking call.
I prefer using this method, as dealing with a timeout approach results in run-time behaviour issues (either a call waiting too long, or a call timing out too quickly). -
Are the experts wrong about non-blocking SocketChannels?
Everyone says to use the new SocketChannel and Selector for "highly scalable" server applications. So I ran a couple of tests using non-blocking (via Selector) and thread-per-connection SocketChannels.
The Selector version consumes 8x more cpu than the thread-per-connecton version!
Using JDK 1.4.1 FCS on Win2K, with 1000 socket connections each sending 1k bytes per second, the Selector version was consuming 40% cpu with 10 threads; the thread-per-connection version (using blocking SocketChannels) was only consuming about 5% cpu with 1009 threads.
So, are the experts wrong? Is there a performance problem when number of SocketChannels exceed a certain threshold?
For anyone interested, here's the source code:
Non-Blocking Server using Selector
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Server4 implements Runnable
private static int port = 80;
public static void main(String args[]) throws Exception
Server4 server = new Server4();
Thread thread = new Thread(server);
thread.setDaemon(true);
thread.start();
thread.join();
public Server4() throws IOException
ServerSocketChannel server = ServerSocketChannel.open();
InetSocketAddress isa = new InetSocketAddress(port);
server.configureBlocking(false);
server.socket().bind(isa);
m_selector = Selector.open();
server.register(m_selector, SelectionKey.OP_ACCEPT);
Charset utf8 = Charset.forName("UTF-8");
m_decoder = utf8.newDecoder();
m_encoder = utf8.newEncoder();
public void run()
int count = 0;
try
ByteBuffer buffer = ByteBuffer.allocateDirect(2048);
//FileOutputStream fos = new FileOutputStream("server4.dat");
//FileChannel fc = fos.getChannel();
while (m_selector.select() > 0)
Set keys = m_selector.selectedKeys();
for (Iterator itr = keys.iterator(); itr.hasNext(); )
SelectionKey key = (SelectionKey) itr.next();
itr.remove();
if (key.isAcceptable())
System.out.println("accept: " + (++count));
ServerSocketChannel server
= (ServerSocketChannel) key.channel();
SocketChannel channel = server.accept();
channel.configureBlocking(false);
channel.register(m_selector, SelectionKey.OP_READ);
else
SocketChannel channel = null;
try
if (key.isReadable())
channel = (SocketChannel) key.channel();
int bytes = channel.read(buffer);
if (bytes <= 0) // Linux does not throw IOException
channel.close(); // will also cancel key
System.out.println("connection closed " + count);
else
buffer.flip();
//fc.write(buffer);
buffer.clear();
catch (IOException ioe) // connection closed by client
System.out.println("readable: " + ioe.getMessage());
sm_logger.log(Level.INFO, ioe.getMessage(), ioe);
Throwable cause = ioe.getCause();
if (cause != null)
System.out.println("cause: "
+ cause.getClass().getName()
+ ": " + cause.getMessage());
channel.close(); // will also cancel key
--count;
catch (IOException e)
System.out.println("run: " + e.getMessage());
sm_logger.log(Level.SEVERE, e.getMessage(), e);
catch (Exception e)
System.out.println("run: " + e.getMessage());
sm_logger.log(Level.SEVERE, e.getMessage(), e);
private Selector m_selector;
private CharsetDecoder m_decoder;
private CharsetEncoder m_encoder;
private static Logger sm_logger = Logger.getLogger("Server");
Thread-Per-Connection Server
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
public class MultiThreadServer implements Runnable
private static int port = 80;
public static void main(String[] args) throws Exception
ServerSocketChannel server = ServerSocketChannel.open();
InetSocketAddress isa = new InetSocketAddress(port);
server.socket().bind(isa);
int count = 0;
while (true)
SocketChannel channel = server.accept();
System.out.println("accept: " + (++count));
MultiThreadServer worker = new MultiThreadServer(channel);
Thread thread = new Thread(worker);
thread.setDaemon(true);
thread.start();
public MultiThreadServer(SocketChannel channel) throws IOException
m_channel = channel;
public void run()
ByteBuffer buffer = ByteBuffer.allocateDirect(2048);
int bytes = 0;
try
while ((bytes = m_channel.read(buffer)) > 0)
buffer.flip();
// process buffer
buffer.clear();
System.out.println("connection closed");
m_channel.close();
catch (IOException e)
System.out.println("run: " + e.getMessage());
sm_logger.log(Level.SEVERE, e.getMessage(), e);
catch (Exception e)
System.out.println("run: " + e.getMessage());
sm_logger.log(Level.SEVERE, e.getMessage(), e);
private SocketChannel m_channel;
private static Logger sm_logger = Logger.getLogger("MultiThreadServer");
Client
import java.io.*;
import java.net.*;
import java.nio.*;
import java.nio.channels.*;
import java.nio.charset.*;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
public class MultiClient implements Runnable
public static void main(String[] args) throws Exception
if (args.length < 1)
System.out.println("usage: java MultiClient number [host]");
System.exit(1);
int number = Integer.parseInt(args[0]);
String host = (args.length == 2) ? args[1] : "localhost" ;
Thread[] threads = new Thread [number];
InetSocketAddress address = new InetSocketAddress(host, 80);
for (int i = 0; i < number; i++)
MultiClient client = new MultiClient(address, Integer.toString(i));
threads[i] = new Thread(client);
threads.setDaemon(true);
for (int i = 0; i < number; i++)
threads[i].start();
for (int i = 0; i < number; i++)
threads[i].join();
public MultiClient(InetSocketAddress address, String id)
throws InterruptedException, IOException
m_id = id;
Charset charset = Charset.forName("UTF-8");
m_decoder = charset.newDecoder();
m_encoder = charset.newEncoder();
m_channel = SocketChannel.open();
m_channel.connect(address);
if (id.equals("0"))
Socket socket = m_channel.socket();
System.out.println("SO_SNDBUF=" + socket.getSendBufferSize()
+ ",SO_TIMEOUT=" + socket.getSoTimeout()
+ ",SO_KEEPALIVE=" + socket.getKeepAlive());
byte[] buf = new byte [1024]; // bufsize = 1K
Arrays.fill(buf, (byte) m_id.charAt(0));
m_buffer = ByteBuffer.allocateDirect(1024);
m_buffer.put(buf);
m_buffer.flip();
Thread.currentThread().sleep(50L);
public void run()
System.out.print(m_id);
try
while (true)
m_channel.write(m_buffer);
m_buffer.rewind();
Thread.currentThread().sleep(1000L);
catch (IOException ioe)
ioe.printStackTrace();
catch (InterruptedException ie)
System.err.println(ie.toString());
private String m_id;
private CharsetEncoder m_encoder;
private CharsetDecoder m_decoder;
private SocketChannel m_channel;
private ByteBuffer m_buffer;{This is a crosspost. I posted this earlier today at http://forum.java.sun.com/thread.jsp?forum=4&thread=319822 before I stumbled on a search phrase that located this older thread.
All follow-ups should be on haam's thread instead of mine. The important point below is that NIO select() behavior (vs. threading IO) is [b]worse under Windows but better under Solaris. This seems fundamentally broken. }
My company sells a scalable multi-user server platform built on Java 2.
It runs under Java 1.3.1 (and 1.4.0 windows) using multiple threads for communications, and 1.4.x (unix) using NIO. We were happy to see that 1.4.1 (windows) fixed the problem drastically limiting the number of selectable ports. :-)
The bad news is that whatever the VM is doing "under the sheets" to fix the problem seems to perform very poorly in terms of CPU:
I compared connecting 500 simulated users to a Solaris 8 and a Win2K box. These users were in 25 chat rooms, each sending a chat message every 30 seconds. (There was plenty of memory on each machine. There was no swapping in either case. Clock/CPU type doesn't matter as this isn't about comparing a machine to a machine, but different load characteristics -within- a machine environment.)
Threaded IO NIO/Select
Solaris 1.4.1 20-30% 15- 20%
Windows 1.4.1 40-50% 95-100%Numbers are % of CPU as reported by 'top' and the Win2K task manager.
Both platforms showed the expected significant improvement in memory usage when moving from standard threaded IO to NIO.
Strangely, the Windows implementation of the VM showed a significant (and unexpected) degradation of NIO performance vs. the threaded model, whereas the Solaris VM behaved as expected: NIO outperformed threaded IO.
Our best guess is that the Selector fix in 1.4.1 is implemented in some cpu-intensive way; perhaps polling. As a result, we still can't use NIO for Wintel boxes running our server. :-( To us, Selector
is still broken.
Has anyone else seen results like this? Have we missed some configuration parameter that will fix this?
I thought the big upside of using select() was supposed to be performance. :-P
F. Randall Farmer
State Software, Inc.
http://www.statesoftware.com -
Problem about Non-blocking socket's read and write
my aim is:when I open a socketchannel,I can use this socket which can continue send and get messages!(for example:open a socket,send a loging message,server echo,if passed,use the same socket sending other message,get echo messages....
Here is problem sample codes:
void ConnectServer() throws IOException
bf = ByteBuffer.allocateDirect(1024);
InetSocketAddress ad = new InetSocketAddress(this.servername,this.serverport);
this.clientsocketchannel = SocketChannel.open(); //set socketchannel
this.clientsocketchannel.configureBlocking(false);
this.clientsocketchannel.connect(ad);
this.slt = Selector.open();
this.clientsocketchannel.register (this.slt,SelectionKey.OP_CONNECT|SelectionKey.OP_READ|SelectionKey.OP_WRITE);
//send data
private void SendMessage(byte[] SendMessage)throws IOException
while (this.slt.select() > 0)//sth wrong!when I test,slt.select(500)=0
Set readykey = slt.selectedKeys();
Iterator readyitor = readykey.iterator();
while (readyitor.hasNext())
SelectionKey skey = (SelectionKey) readyitor.next();
readyitor.remove();
if (skey.isWritable())
SocketChannel keychannel = (SocketChannel) skey.channel();
keychannel.write(ByteBuffer.wrap(this.sendmessage));
}//end while
}//end while
//get data
private void GetEchoMessage()throws IOException
while(this.slt.select(500) > 0)//sth wrong!when I test,slt.select(500)=0
Set readykey = slt.selectedKeys();
Iterator readyitor = readykey.iterator();
while (readyitor.hasNext())
SelectionKey skey = (SelectionKey) readyitor.next();
readyitor.remove();
if (skey.isWritable())
SocketChannel keychannel = (SocketChannel) skey.channel();
keychannel.read(bf);
public static void main(String[] arg)
connectserver(..);
SendMessage(...);
GetEchoMessage();
SendMessage(...);
GetEchoMessage();private void ConnectServer() throws IOException
� bf = ByteBuffer.allocateDirect(1024);
�� InetSocketAddress ad = new InetSocketAddress(this.servername,this.serverport);
�� this.clientsocketchannel = SocketChannel.open(); //set
socketchannel
�� this.clientsocketchannel.configureBlocking(false);
�� this.clientsocketchannel.connect(ad);
�� this.slt = Selector.open(); � this.clientsocketchannel.registerthis.slt,SelectionKey.OP_CONNECT|SelectionKey.OP_READ|SelectionKey.OP_WRITE);
<b>
//send data</b>
private void SendMessage(byte[] SendMessage)throws IOException
� while (this.slt.select() > 0)//<font color="#FF0000"><i>wrong,when test,this.slt.select(500)=0,why??</i></font>
�{
��� Set readykey = slt.selectedKeys();
��� Iterator readyitor = readykey.iterator();
��� while (readyitor.hasNext())
��� {
������ SelectionKey skey = (SelectionKey) readyitor.next();
������ readyitor.remove();
������ if (skey.isWritable())
������ {
�������� SocketChannel keychannel = (SocketChannel) skey.channel();
�������� keychannel.write(ByteBuffer.wrap(this.sendmessage));
������ }
��� }//end while
� }//end while�
<b>
//get data</b>
private void GetEchoMessage()throws IOException
� while(this.slt.select(500) > 0)<font color="#FF0000"><i>//wrong,when
test,this.slt.select(500)=0</i></font>
� {
��� Set readykey = slt.selectedKeys();
��� Iterator readyitor = readykey.iterator();
��� while (readyitor.hasNext())
��� {
����� SelectionKey skey = (SelectionKey) readyitor.next();
����� readyitor.remove();
����� if (skey.isWritable())
����� {
������� SocketChannel keychannel = (SocketChannel) skey.channel();
������� keychannel.read(bf);
����� }
��� }
� }
public static void main(String[] arg)
� ......
� connectserver(..);
� SendMessage(...);
� GetEchoMessage();
� .......
� SendMessage(...);
� GetEchoMessage();
� ....... -
I'd like to use the OCCI interface in a non-blocking mode. Does anyone have any experience with this? Looks like I need to use a combo of OCI and OCCI calls to set the OCI_HTYPE_SERVER handle with the OCI_ATTR_NONBLOCKING MODE. However, my stmt->executeQuery() method seems to be throwing an exceptions, which I would have though would have been the OCI_STILL_EXECUTING error, but it's not. The exeception is an "ORA-32103 error from OCI call". If I continue to do another stmt->executeQuery(), I eventually get an access exception.
Anyone have any code snippets using OCCI in non-blocking mode?I use threads. ACE/TAO to be precise.
I have singleton class that manages the Oracle environment and connection as well as being a statement
factory.
Just have a thread perform your stmt->executeXXX() method and you will not need to worry about non-blocking.
That's how I do it and it works well. -
About NIO non-blocking socket write method behavior
Hi all -
I hope anyone could help in this issue.
Assume you create a NIO socket and configure its channel in non blocking mode:
channel.configureBlocking(false);
then you write a byte buffer into it:
int sentBytesNum = channel.write(byteBuffer);
What are the possibilities of sentBytesNum value? I am sure of two possibilities, which are:
- all data sent so sentBytesNum equals byteBuffer data size (limit minus position before sending) (after sending the limit and position of byteBuffer are the same)
- no data is sent so sentBytesNum is zero and byteBuffer limit and postion did not change, so we shall use a write selector to test when the channel will be ready for write to write the data.
What I am not sure about and need someone to confirm is the third possibility:
- only a part of data is sent (according to the available free space of socket output buffer) so sentBytesNum is more than zero but less than data size and byteBuffer position is advanced by the value of sentBytesNum, might this possibility happen??
If yes, so we should manage to hold the non sent part of byteBuffer till the channel becomes ready for write (we can know that using write selector) so we can write it to channel???
Thanks for help,
RockaYes, case three can occur. The usual NIO write loop looks like this:
int count = 0;
while (buf.position() > 0)
buf.flip();
count = ch.write(buf);
buf.compact();
if (count == 0)
break;
}This will run until buf.position() == 0 or count == 0. If the partial write case happens it will loop one more time and probably get a 0 count.
At the end of the loop, if buf.position() > 0 there is still unwritten data and at this point you should register for OP_WRITE and return to the selector. Otherwise if there is no data unwritten you should deregister OP_WRITE as you have nothing to write and aren't interested in the event any longer.
If you are reading something and writing at the same time the logic goes like this:
while (inch.read(buf) >= 0 || buf.position() > 0)
// etc
}This will read until EOF occurs and either buf.position() is zero or a zero length write occurred. -
What means about Non-local Process blocks cleaned out in RACalert log
Hi Experts,
We have 4 nodes oracle 11.1 RAC in redhat5.1.
I saw lots of message about Non-local Process blocks cleaned out in alert log files today.
such as
Tue Sep 8 16:31:04 2009
Reconfiguration started (old inc 18, new inc 20)
List of nodes:
0 1 2 3
Global Resource Directory frozen
Communication channels reestablished
* domain 0 valid = 1 according to instance 0
Tue Sep 8 16:31:04 2009
Master broadcasted resource hash value bitmaps
Non-local Process blocks cleaned out
Tue Sep 8 16:43:46 2009
LMS 0: 0 GCS shadows cancelled, 0 closed
Tue Sep 8 16:43:46 2009
LMS 1: 0 GCS shadows cancelled, 0 closed
Set master node info
Submitted all remote-enqueue requests
Dwn-cvts replayed, VALBLKs dubious
All grantable enqueues granted
Does some expert above message for me?
Thanks
JimThanks- good observation.
Unusual, perhaps, but it is what we need in our setting. And- allegedly this is supported / encouraged based on my understanding of the OS X Server docs. I don't have any control over the AD server (since it's in the university-level IT management's hands) but I -do-, of course, have control over my own server. So I just want to use their authentication (and save my students / lab folk the trouble of having multiple logins, etc).
You make a good point / observation / point-of-debuggery. Indeed, if I set the client machines to use -only- the main campus AD server (and thus allow logins from everyone on campus) it works first time. So it is some interesting interaction betwixt the Mac OS Server and the client methinks. In fact, across campus, all the 'public' machines are simply bound to the AD server and you can just log in that way. -
SELECT of OCILobLocator in Non Blocking mode
Hi all.
I have problem:
I try select BLOB field into OCILobLocator* buffer in Non Blocking mode, and receive 'ORA-03106: fatal two-task communication protocol error' sometimes.
Details:
Application contains two threads : 1. select blob field, 2. update it.
I tried separate update and select to different apps (and run its in one time) - problem reproduced.
problem reproduced for OCIStmtFetch and OCIStmtFetch2.
If disable non blocking mode - problem disappear.
if error appear - record level error code contains 1405. Need wait few minutes for error message appearing (~1 minute in my case).
Using of OCI_DEFAULT in OCIDefineByPos instead OCI_DYNAMIC_FETCH don't solve problem.
I use oracle server and client library with version 10.2.0.4
Output sample:
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #877: 1405
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #54: 1405
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #877: 1405
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #54: 1405
Can anybody help me ?
m.b. exists workaround ?
#include <iostream>
#include <sstream>
#include <assert.h>
#include <oci.h>
#define _DYN 1
before run this test run next sql at DB:
CREATE TABLE ADSERVERTEST_BLOB(id NUMBER(10), text BLOB);
BEGIN
FOR i IN 0..999 LOOP
INSERT INTO ADSERVERTEST_BLOB(id, text) VALUES(i, utl_raw.cast_to_raw('init'));
END LOOP;
END;
template<typename Type, unsigned long TypeId>
class OCIHandlePtr
public:
OCIHandlePtr(): handle_(0) {}
OCIHandlePtr(Type* handle): handle_(handle) {}
~OCIHandlePtr()
reset(0);
void reset(Type* handle)
if(handle_)
sword result;
if((result = OCIHandleFree(
handle_,
TypeId)) != OCI_SUCCESS)
assert(0);
std::cerr << "Can't make OCIHandleFree" << std::endl;
handle_ = handle;
Type* get()
return handle_;
Type*& fill()
reset(0);
return handle_;
private:
Type* handle_;
template<typename Type, unsigned long TypeId>
class OCIDescriptorPtr
public:
OCIDescriptorPtr(): handle_(0) {}
OCIDescriptorPtr(Type* handle): handle_(handle) {}
~OCIDescriptorPtr()
reset(0);
void reset(Type* handle)
if(handle_)
sword result;
if((result = OCIDescriptorFree(
handle_,
TypeId)) != OCI_SUCCESS)
std::cerr << "Can't make OCIDescriptorFree" << std::endl;
handle_ = handle;
Type* get()
return handle_;
Type*& fill()
reset(0);
return handle_;
private:
Type* handle_;
void throw_oci_error(
const char* fun,
const char* oci_op,
long status,
OCIError* oci_error_handler,
const char* query = 0)
std::cerr << fun << ": can't make " << oci_op << ": status = " << status;
if(status == OCI_SUCCESS_WITH_INFO ||
status == OCI_ERROR)
std::cerr << ", message = '";
text err_buf[1024] = "";
sb4 err_code = 0;
OCIErrorGet(
oci_error_handler,
(ub4)1,
0,
&err_code,
err_buf,
sizeof(err_buf),
(ub4)OCI_HTYPE_ERROR);
std::cerr << err_buf << "', error code = " << err_code;
exit(1);
if(query)
std::cerr << ", sql = " << query;
OCIHandlePtr<OCIEnv, OCI_HTYPE_ENV> environment_handle;
void connect(
OCIEnv* environment_handle,
const char* db,
const char* user,
const char* password,
OCIHandlePtr<OCIError, OCI_HTYPE_ERROR>& error_handle,
OCIHandlePtr<OCIServer, OCI_HTYPE_SERVER>& server_handle,
OCIHandlePtr<OCISession, OCI_HTYPE_SESSION>& session_handle,
OCIHandlePtr<OCISvcCtx, OCI_HTYPE_SVCCTX>& svc_context_handle)
static const char* FUN = "connect()";
sword result;
// allocate an error handle
if((result = OCIHandleAlloc(
environment_handle,
(void **) &error_handle.fill(),
OCI_HTYPE_ERROR,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// allocate a server handle
if((result = OCIHandleAlloc(
environment_handle,
(void **) &server_handle.fill(),
OCI_HTYPE_SERVER,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
if((result = OCIServerAttach(
server_handle.get(),
error_handle.get(),
(text*)db,
strlen(db),
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIServerAttach", result, error_handle.get());
// allocate a service handle
if((result = OCIHandleAlloc(
environment_handle,
(void **) &svc_context_handle.fill(),
OCI_HTYPE_SVCCTX,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// set the server attribute in the service context handle
if((result = OCIAttrSet(
svc_context_handle.get(),
OCI_HTYPE_SVCCTX,
server_handle.get(),
sizeof(OCIServer*),
OCI_ATTR_SERVER,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// allocate a user session handle
if((result = OCIHandleAlloc(
environment_handle,
(void **)&session_handle.fill(),
OCI_HTYPE_SESSION,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// set username and password attributes in user session handle
if((result = OCIAttrSet(
session_handle.get(),
OCI_HTYPE_SESSION,
(text*)user,
strlen(user),
OCI_ATTR_USERNAME,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
if((result = OCIAttrSet(
session_handle.get(),
OCI_HTYPE_SESSION,
(text*)password,
strlen(password),
OCI_ATTR_PASSWORD,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
// start the session
if((result = OCISessionBegin(
svc_context_handle.get(),
error_handle.get(),
session_handle.get(),
OCI_CRED_RDBMS,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCISessionBegin", result, error_handle.get());
// set the user session attribute in the service context handle
if((result = OCIAttrSet(
svc_context_handle.get(),
OCI_HTYPE_SVCCTX,
session_handle.get(),
sizeof(OCISession*),
OCI_ATTR_SESSION,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
ub1 attr_value = 1;
if((result = OCIAttrSet(
server_handle.get(),
OCI_HTYPE_SERVER,
&attr_value,
sizeof(attr_value),
OCI_ATTR_NONBLOCKING_MODE,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
void disconnect(
OCIEnv* environment_handle,
OCIError* error_handle,
OCIServer* server_handle,
OCISession* session_handle,
OCISvcCtx* svc_context_handle)
static const char* FUN = "disconnect()";
sword result;
if((result = OCISessionEnd(
svc_context_handle,
error_handle,
session_handle,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCISessionEnd", result, error_handle);
if((result = OCIServerDetach(
server_handle,
error_handle,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIServerDetach", result, error_handle);
OCILobLocator* FETCH_BUFFER_1[10000*1024];
char IND_BUFFER_1[10000*1024];
ub2 ERROR_BUFFER_1[1024];
OCIDefine* define_handle_1;
void clear_blob_buf(
OCILobLocator** buf,
unsigned long fetch_size)
for(unsigned long i = 0; i < 1024; ++i)
OCIDescriptorFree(
buf,
(ub4)OCI_DTYPE_LOB);
::memset(buf, 0, fetch_size * 1024);
uint32_t RET_LEN4;
sb4 oci_blob_callback(
dvoid* ctx,
OCIDefine* define,
ub4 iter,
dvoid** bufpp,
ub4** alenpp,
ub1* piecep,
dvoid** indpp,
ub2** rcodepp)
RET_LEN4 = sizeof(OCILobLocator*);
*bufpp = FETCH_BUFFER_1[iter];
*alenpp = &RET_LEN4;
*piecep = OCI_ONE_PIECE;
*indpp = IND_BUFFER_1 + iter;
*rcodepp = ERROR_BUFFER_1 + iter;
//std::cout << "iter: " << iter << std::endl;
return OCI_CONTINUE;
int define_column(
OCIEnv* environment_handle,
OCISvcCtx* svc_handle,
OCIStmt* stmt_handle,
OCIError* error_handle,
OCIDefine** define_handle,
unsigned long pos,
long oci_type,
unsigned long fetch_size,
OCILobLocator** buf,
char* ind_buf,
ub2* err_buf)
static const char* FUN = "define_column()";
sword result;
if(oci_type == SQLT_BLOB)
::memset(buf, 0, fetch_size * 1024);
for(int i = 0; i < 1024; ++i)
if((result = OCIDescriptorAlloc(
(dvoid*)environment_handle,
(dvoid**)&buf[i],
(ub4)OCI_DTYPE_LOB,
(size_t)0,
(dvoid**)0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIDescriptorAlloc", result, error_handle);
ub2 size = 0;
OCIDescriptorPtr<OCIParam, OCI_DTYPE_PARAM> param_handle;
// ub2 oci_data_type = 0;
if((result = OCIParamGet(
stmt_handle,
OCI_HTYPE_STMT,
error_handle,
reinterpret_cast<void**>(¶m_handle.fill()),
pos)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIParamGet", result, error_handle);
if((result = OCIAttrGet(
param_handle.get(),
OCI_DTYPE_PARAM,
&size,
0,
OCI_ATTR_DATA_SIZE,
error_handle)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrGet", result, error_handle);
if((result = OCIDefineByPos(
stmt_handle,
define_handle,
error_handle,
pos,
# ifdef _DYN
0,
-1,
#else
buf,
fetch_size,
#endif
oci_type,
ind_buf,
0,
err_buf, // ptr to array of column-level return codes
# ifdef _DYN
OCI_DYNAMIC_FETCH
# else
OCI_DEFAULT
# endif
)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIDefineByPos", result, error_handle);
# ifdef _DYN
if((result = OCIDefineDynamic(
*define_handle,
error_handle,
0,
oci_blob_callback)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIDefineByPos", result, error_handle);
# endif
return 0;
int define_columns(
OCIEnv* environment_handle,
OCISvcCtx* svc_handle,
OCIStmt* stmt_handle,
OCIError* error_handle)
static const char* FUN = "define_columns()";
define_handle_1 = 0;
int pos = 1;
::memset(ERROR_BUFFER_1, 0, 1024 * sizeof(ERROR_BUFFER_1[0]));
define_column(
environment_handle,
svc_handle,
stmt_handle,
error_handle,
&define_handle_1,
pos++,
SQLT_BLOB,
sizeof(OCILobLocator*),
FETCH_BUFFER_1,
IND_BUFFER_1,
ERROR_BUFFER_1);
return 0;
int execute_select(
const char* db,
const char* user,
const char* password)
static const char* FUN = "execute_select()";
const unsigned long FETCH_COUNT = 1024;
OCIHandlePtr<OCIError, OCI_HTYPE_ERROR> error_handle;
OCIHandlePtr<OCIServer, OCI_HTYPE_SERVER> server_handle;
OCIHandlePtr<OCISession, OCI_HTYPE_SESSION> session_handle;
OCIHandlePtr<OCISvcCtx, OCI_HTYPE_SVCCTX> svc_context_handle;
connect(
environment_handle.get(),
db,
user,
password,
error_handle,
server_handle,
session_handle,
svc_context_handle);
OCIHandlePtr<OCIStmt, OCI_HTYPE_STMT> stmt_handle;
sword result;
if((result = OCIHandleAlloc(
environment_handle.get(),
(void**)&stmt_handle.fill(),
OCI_HTYPE_STMT,
0,
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
const char QUERY[] = "SELECT text FROM ADSERVERTEST_BLOB";
ub4 rows = 0;
if((result = OCIAttrSet(
stmt_handle.get(),
OCI_HTYPE_STMT,
(dvoid *)&rows,
(ub4)sizeof(ub4),
OCI_ATTR_PREFETCH_ROWS,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(
FUN, "OCIAttrSet(OCI_ATTR_PREFETCH_ROWS)", result, error_handle.get());
if((result = OCIStmtPrepare(
stmt_handle.get(),
error_handle.get(),
(text*)QUERY,
strlen(QUERY),
OCI_NTV_SYNTAX,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIStmtPrepare", result, error_handle.get());
ub2 stmt_type;
if((result = OCIAttrGet(
stmt_handle.get(),
OCI_HTYPE_STMT,
&stmt_type,
0,
OCI_ATTR_STMT_TYPE,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrGet", result, error_handle.get());
ub4 prev_fetched = 0;
while((result = OCIStmtExecute(
svc_context_handle.get(),
stmt_handle.get(),
error_handle.get(),
0,
0,
0,
0,
OCI_DEFAULT)) != OCI_SUCCESS)
if(result != OCI_STILL_EXECUTING)
throw_oci_error(FUN, "OCIStmtExecute", result, error_handle.get());
define_columns(
environment_handle.get(),
svc_context_handle.get(),
stmt_handle.get(),
error_handle.get());
ub4 all_fetched_count = 0;
while(true)
while((result = OCIStmtFetch2(
stmt_handle.get(),
error_handle.get(),
FETCH_COUNT,
OCI_FETCH_NEXT,
1,
OCI_DEFAULT)) == OCI_STILL_EXECUTING
# ifdef _DYN
// || result == OCI_NEED_DATA
# endif
if (result != OCI_SUCCESS &&
result != OCI_NO_DATA &&
result != OCI_SUCCESS_WITH_INFO)
std::cerr << FUN << ": can't make OCIStmtFetch2: status = " << result;
std::cerr << ", message = '";
text err_buf[1024] = "";
sb4 err_code = 0;
OCIErrorGet(
error_handle.get(),
(ub4)1,
0,
&err_code,
err_buf,
sizeof(err_buf),
(ub4)OCI_HTYPE_ERROR);
std::cerr << err_buf << "', error code = " << err_code << ", row errors: ";
for(const ub2* cur = ERROR_BUFFER_1;
cur < ERROR_BUFFER_1 + 1024; ++cur)
if(*cur)
std::cerr << "#" << (cur - ERROR_BUFFER_1) << ": " <<
*cur << std::endl;
ub4 fetched_count = 0;
if((result = OCIAttrGet (
stmt_handle.get(),
OCI_HTYPE_STMT,
&fetched_count,
0,
OCI_ATTR_ROW_COUNT,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrGet", result, error_handle.get());
all_fetched_count += fetched_count;
if(fetched_count > 0)
for(unsigned long i = 0; i < fetched_count - 1; ++i)
ub4 lob_size;
while((result = OCILobGetLength(
svc_context_handle.get(),
error_handle.get(),
FETCH_BUFFER_1[i],
&lob_size)) == OCI_STILL_EXECUTING)
if(result != OCI_SUCCESS)
throw_oci_error(FUN, "OCILobGetLength", result, error_handle.get());
std::cout << "#" << i << ": ind = " << (unsigned long)IND_BUFFER_1[i] <<
", len = " << lob_size << std::endl;
if(fetched_count - prev_fetched < FETCH_COUNT)
break;
prev_fetched = fetched_count;
clear_blob_buf(
FETCH_BUFFER_1,
sizeof(OCILobLocator*));
while((result = OCIStmtFetch(
stmt_handle.get(),
error_handle.get(),
0,
OCI_FETCH_NEXT,
OCI_DEFAULT)) == OCI_STILL_EXECUTING
disconnect(
environment_handle.get(),
error_handle.get(),
server_handle.get(),
session_handle.get(),
svc_context_handle.get());
return 0;
int execute_update(
const char* db,
const char* user,
const char* password)
static const char* FUN = "execute_update()";
OCIHandlePtr<OCIError, OCI_HTYPE_ERROR> error_handle;
OCIHandlePtr<OCIServer, OCI_HTYPE_SERVER> server_handle;
OCIHandlePtr<OCISession, OCI_HTYPE_SESSION> session_handle;
OCIHandlePtr<OCISvcCtx, OCI_HTYPE_SVCCTX> svc_context_handle;
connect(
environment_handle.get(),
db,
user,
password,
error_handle,
server_handle,
session_handle,
svc_context_handle);
OCIHandlePtr<OCIStmt, OCI_HTYPE_STMT> stmt_handle;
for(int i = 0; i < 1000; ++i)
sword result;
if((result = OCIHandleAlloc(
environment_handle.get(),
(void**)&stmt_handle.fill(),
OCI_HTYPE_STMT,
0,
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
std::ostringstream sql;
std::string str;
std::string et("\xEB\xB2\x88");
unsigned long rep = ::rand() % 500 + 1;
str.reserve(rep*et.size());
for(unsigned long ei = 0; ei < rep; ++ei)
str.append(et);
sql << "BEGIN " <<
"UPDATE ADSERVERTEST_BLOB SET text = "
"utl_raw.cast_to_raw('" << str << "') "
"WHERE id = " << i <<
"END;";
if((result = OCIStmtPrepare(
stmt_handle.get(),
error_handle.get(),
(text*)sql.str().c_str(),
sql.str().length(),
OCI_NTV_SYNTAX,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIStmtPrepare", result, error_handle.get());
while((result = OCIStmtExecute(
svc_context_handle.get(),
stmt_handle.get(),
error_handle.get(),
1,
0,
0,
0,
OCI_DEFAULT)) != OCI_SUCCESS)
if(result != OCI_STILL_EXECUTING)
throw_oci_error(FUN, "OCIStmtExecute", result, error_handle.get());
disconnect(
environment_handle.get(),
error_handle.get(),
server_handle.get(),
session_handle.get(),
svc_context_handle.get());
return 0;
void* select_thread(void* ctx)
while(true)
execute_select(
"//oraclept.ocslab.com/addbpt.ocslab.com",
"bs_unittest_4",
"adserver");
// std::cout << "select finished" << std::endl;
return ctx;
void* update_thread(void* ctx)
while(true)
execute_update(
"//oraclept.ocslab.com/addbpt.ocslab.com",
"bs_unittest_4",
"adserver");
// std::cout << "update finished" << std::endl;
return ctx;
int main()
static const char* FUN = "main()";
sword result;
// allocate an environment handle
if((result = OCIEnvCreate(
&environment_handle.fill(),
OCI_OBJECT | OCI_THREADED,
0, // context
0, // malloc
0, // realloc
0, // free
0, // extra memory to allocate
0) // pointer to user-memory
) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIEnvCreate", result, 0);
pthread_t th1, th2;
pthread_create(&th1, 0, select_thread, 0);
pthread_create(&th2, 0, update_thread, 0);
pthread_join(th1, 0);
pthread_join(th2, 0);
return 0;
Edited by: user13011391 on 20.04.2010 5:50
Edited by: user13011391 on 20.04.2010 6:00
Edited by: user13011391 on 20.04.2010 6:15Hi all.
I have problem:
I try select BLOB field into OCILobLocator* buffer in Non Blocking mode, and receive 'ORA-03106: fatal two-task communication protocol error' sometimes.
Details:
Application contains two threads : 1. select blob field, 2. update it.
I tried separate update and select to different apps (and run its in one time) - problem reproduced.
problem reproduced for OCIStmtFetch and OCIStmtFetch2.
If disable non blocking mode - problem disappear.
if error appear - record level error code contains 1405. Need wait few minutes for error message appearing (~1 minute in my case).
Using of OCI_DEFAULT in OCIDefineByPos instead OCI_DYNAMIC_FETCH don't solve problem.
I use oracle server and client library with version 10.2.0.4
Output sample:
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #877: 1405
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #54: 1405
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #877: 1405
execute_select(): can't make OCIStmtFetch2: status = -1, message = 'ORA-03106: fatal two-task communication protocol error
', error code = 3106, row errors: #54: 1405
Can anybody help me ?
m.b. exists workaround ?
#include <iostream>
#include <sstream>
#include <assert.h>
#include <oci.h>
#define _DYN 1
before run this test run next sql at DB:
CREATE TABLE ADSERVERTEST_BLOB(id NUMBER(10), text BLOB);
BEGIN
FOR i IN 0..999 LOOP
INSERT INTO ADSERVERTEST_BLOB(id, text) VALUES(i, utl_raw.cast_to_raw('init'));
END LOOP;
END;
template<typename Type, unsigned long TypeId>
class OCIHandlePtr
public:
OCIHandlePtr(): handle_(0) {}
OCIHandlePtr(Type* handle): handle_(handle) {}
~OCIHandlePtr()
reset(0);
void reset(Type* handle)
if(handle_)
sword result;
if((result = OCIHandleFree(
handle_,
TypeId)) != OCI_SUCCESS)
assert(0);
std::cerr << "Can't make OCIHandleFree" << std::endl;
handle_ = handle;
Type* get()
return handle_;
Type*& fill()
reset(0);
return handle_;
private:
Type* handle_;
template<typename Type, unsigned long TypeId>
class OCIDescriptorPtr
public:
OCIDescriptorPtr(): handle_(0) {}
OCIDescriptorPtr(Type* handle): handle_(handle) {}
~OCIDescriptorPtr()
reset(0);
void reset(Type* handle)
if(handle_)
sword result;
if((result = OCIDescriptorFree(
handle_,
TypeId)) != OCI_SUCCESS)
std::cerr << "Can't make OCIDescriptorFree" << std::endl;
handle_ = handle;
Type* get()
return handle_;
Type*& fill()
reset(0);
return handle_;
private:
Type* handle_;
void throw_oci_error(
const char* fun,
const char* oci_op,
long status,
OCIError* oci_error_handler,
const char* query = 0)
std::cerr << fun << ": can't make " << oci_op << ": status = " << status;
if(status == OCI_SUCCESS_WITH_INFO ||
status == OCI_ERROR)
std::cerr << ", message = '";
text err_buf[1024] = "";
sb4 err_code = 0;
OCIErrorGet(
oci_error_handler,
(ub4)1,
0,
&err_code,
err_buf,
sizeof(err_buf),
(ub4)OCI_HTYPE_ERROR);
std::cerr << err_buf << "', error code = " << err_code;
exit(1);
if(query)
std::cerr << ", sql = " << query;
OCIHandlePtr<OCIEnv, OCI_HTYPE_ENV> environment_handle;
void connect(
OCIEnv* environment_handle,
const char* db,
const char* user,
const char* password,
OCIHandlePtr<OCIError, OCI_HTYPE_ERROR>& error_handle,
OCIHandlePtr<OCIServer, OCI_HTYPE_SERVER>& server_handle,
OCIHandlePtr<OCISession, OCI_HTYPE_SESSION>& session_handle,
OCIHandlePtr<OCISvcCtx, OCI_HTYPE_SVCCTX>& svc_context_handle)
static const char* FUN = "connect()";
sword result;
// allocate an error handle
if((result = OCIHandleAlloc(
environment_handle,
(void **) &error_handle.fill(),
OCI_HTYPE_ERROR,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// allocate a server handle
if((result = OCIHandleAlloc(
environment_handle,
(void **) &server_handle.fill(),
OCI_HTYPE_SERVER,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
if((result = OCIServerAttach(
server_handle.get(),
error_handle.get(),
(text*)db,
strlen(db),
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIServerAttach", result, error_handle.get());
// allocate a service handle
if((result = OCIHandleAlloc(
environment_handle,
(void **) &svc_context_handle.fill(),
OCI_HTYPE_SVCCTX,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// set the server attribute in the service context handle
if((result = OCIAttrSet(
svc_context_handle.get(),
OCI_HTYPE_SVCCTX,
server_handle.get(),
sizeof(OCIServer*),
OCI_ATTR_SERVER,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// allocate a user session handle
if((result = OCIHandleAlloc(
environment_handle,
(void **)&session_handle.fill(),
OCI_HTYPE_SESSION,
0, // extra memory to allocate
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
// set username and password attributes in user session handle
if((result = OCIAttrSet(
session_handle.get(),
OCI_HTYPE_SESSION,
(text*)user,
strlen(user),
OCI_ATTR_USERNAME,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
if((result = OCIAttrSet(
session_handle.get(),
OCI_HTYPE_SESSION,
(text*)password,
strlen(password),
OCI_ATTR_PASSWORD,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
// start the session
if((result = OCISessionBegin(
svc_context_handle.get(),
error_handle.get(),
session_handle.get(),
OCI_CRED_RDBMS,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCISessionBegin", result, error_handle.get());
// set the user session attribute in the service context handle
if((result = OCIAttrSet(
svc_context_handle.get(),
OCI_HTYPE_SVCCTX,
session_handle.get(),
sizeof(OCISession*),
OCI_ATTR_SESSION,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
ub1 attr_value = 1;
if((result = OCIAttrSet(
server_handle.get(),
OCI_HTYPE_SERVER,
&attr_value,
sizeof(attr_value),
OCI_ATTR_NONBLOCKING_MODE,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrSet", result, error_handle.get());
void disconnect(
OCIEnv* environment_handle,
OCIError* error_handle,
OCIServer* server_handle,
OCISession* session_handle,
OCISvcCtx* svc_context_handle)
static const char* FUN = "disconnect()";
sword result;
if((result = OCISessionEnd(
svc_context_handle,
error_handle,
session_handle,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCISessionEnd", result, error_handle);
if((result = OCIServerDetach(
server_handle,
error_handle,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIServerDetach", result, error_handle);
OCILobLocator* FETCH_BUFFER_1[10000*1024];
char IND_BUFFER_1[10000*1024];
ub2 ERROR_BUFFER_1[1024];
OCIDefine* define_handle_1;
void clear_blob_buf(
OCILobLocator** buf,
unsigned long fetch_size)
for(unsigned long i = 0; i < 1024; ++i)
OCIDescriptorFree(
buf,
(ub4)OCI_DTYPE_LOB);
::memset(buf, 0, fetch_size * 1024);
uint32_t RET_LEN4;
sb4 oci_blob_callback(
dvoid* ctx,
OCIDefine* define,
ub4 iter,
dvoid** bufpp,
ub4** alenpp,
ub1* piecep,
dvoid** indpp,
ub2** rcodepp)
RET_LEN4 = sizeof(OCILobLocator*);
*bufpp = FETCH_BUFFER_1[iter];
*alenpp = &RET_LEN4;
*piecep = OCI_ONE_PIECE;
*indpp = IND_BUFFER_1 + iter;
*rcodepp = ERROR_BUFFER_1 + iter;
//std::cout << "iter: " << iter << std::endl;
return OCI_CONTINUE;
int define_column(
OCIEnv* environment_handle,
OCISvcCtx* svc_handle,
OCIStmt* stmt_handle,
OCIError* error_handle,
OCIDefine** define_handle,
unsigned long pos,
long oci_type,
unsigned long fetch_size,
OCILobLocator** buf,
char* ind_buf,
ub2* err_buf)
static const char* FUN = "define_column()";
sword result;
if(oci_type == SQLT_BLOB)
::memset(buf, 0, fetch_size * 1024);
for(int i = 0; i < 1024; ++i)
if((result = OCIDescriptorAlloc(
(dvoid*)environment_handle,
(dvoid**)&buf[i],
(ub4)OCI_DTYPE_LOB,
(size_t)0,
(dvoid**)0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIDescriptorAlloc", result, error_handle);
ub2 size = 0;
OCIDescriptorPtr<OCIParam, OCI_DTYPE_PARAM> param_handle;
// ub2 oci_data_type = 0;
if((result = OCIParamGet(
stmt_handle,
OCI_HTYPE_STMT,
error_handle,
reinterpret_cast<void**>(¶m_handle.fill()),
pos)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIParamGet", result, error_handle);
if((result = OCIAttrGet(
param_handle.get(),
OCI_DTYPE_PARAM,
&size,
0,
OCI_ATTR_DATA_SIZE,
error_handle)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrGet", result, error_handle);
if((result = OCIDefineByPos(
stmt_handle,
define_handle,
error_handle,
pos,
# ifdef _DYN
0,
-1,
#else
buf,
fetch_size,
#endif
oci_type,
ind_buf,
0,
err_buf, // ptr to array of column-level return codes
# ifdef _DYN
OCI_DYNAMIC_FETCH
# else
OCI_DEFAULT
# endif
)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIDefineByPos", result, error_handle);
# ifdef _DYN
if((result = OCIDefineDynamic(
*define_handle,
error_handle,
0,
oci_blob_callback)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIDefineByPos", result, error_handle);
# endif
return 0;
int define_columns(
OCIEnv* environment_handle,
OCISvcCtx* svc_handle,
OCIStmt* stmt_handle,
OCIError* error_handle)
static const char* FUN = "define_columns()";
define_handle_1 = 0;
int pos = 1;
::memset(ERROR_BUFFER_1, 0, 1024 * sizeof(ERROR_BUFFER_1[0]));
define_column(
environment_handle,
svc_handle,
stmt_handle,
error_handle,
&define_handle_1,
pos++,
SQLT_BLOB,
sizeof(OCILobLocator*),
FETCH_BUFFER_1,
IND_BUFFER_1,
ERROR_BUFFER_1);
return 0;
int execute_select(
const char* db,
const char* user,
const char* password)
static const char* FUN = "execute_select()";
const unsigned long FETCH_COUNT = 1024;
OCIHandlePtr<OCIError, OCI_HTYPE_ERROR> error_handle;
OCIHandlePtr<OCIServer, OCI_HTYPE_SERVER> server_handle;
OCIHandlePtr<OCISession, OCI_HTYPE_SESSION> session_handle;
OCIHandlePtr<OCISvcCtx, OCI_HTYPE_SVCCTX> svc_context_handle;
connect(
environment_handle.get(),
db,
user,
password,
error_handle,
server_handle,
session_handle,
svc_context_handle);
OCIHandlePtr<OCIStmt, OCI_HTYPE_STMT> stmt_handle;
sword result;
if((result = OCIHandleAlloc(
environment_handle.get(),
(void**)&stmt_handle.fill(),
OCI_HTYPE_STMT,
0,
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
const char QUERY[] = "SELECT text FROM ADSERVERTEST_BLOB";
ub4 rows = 0;
if((result = OCIAttrSet(
stmt_handle.get(),
OCI_HTYPE_STMT,
(dvoid *)&rows,
(ub4)sizeof(ub4),
OCI_ATTR_PREFETCH_ROWS,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(
FUN, "OCIAttrSet(OCI_ATTR_PREFETCH_ROWS)", result, error_handle.get());
if((result = OCIStmtPrepare(
stmt_handle.get(),
error_handle.get(),
(text*)QUERY,
strlen(QUERY),
OCI_NTV_SYNTAX,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIStmtPrepare", result, error_handle.get());
ub2 stmt_type;
if((result = OCIAttrGet(
stmt_handle.get(),
OCI_HTYPE_STMT,
&stmt_type,
0,
OCI_ATTR_STMT_TYPE,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrGet", result, error_handle.get());
ub4 prev_fetched = 0;
while((result = OCIStmtExecute(
svc_context_handle.get(),
stmt_handle.get(),
error_handle.get(),
0,
0,
0,
0,
OCI_DEFAULT)) != OCI_SUCCESS)
if(result != OCI_STILL_EXECUTING)
throw_oci_error(FUN, "OCIStmtExecute", result, error_handle.get());
define_columns(
environment_handle.get(),
svc_context_handle.get(),
stmt_handle.get(),
error_handle.get());
ub4 all_fetched_count = 0;
while(true)
while((result = OCIStmtFetch2(
stmt_handle.get(),
error_handle.get(),
FETCH_COUNT,
OCI_FETCH_NEXT,
1,
OCI_DEFAULT)) == OCI_STILL_EXECUTING
# ifdef _DYN
// || result == OCI_NEED_DATA
# endif
if (result != OCI_SUCCESS &&
result != OCI_NO_DATA &&
result != OCI_SUCCESS_WITH_INFO)
std::cerr << FUN << ": can't make OCIStmtFetch2: status = " << result;
std::cerr << ", message = '";
text err_buf[1024] = "";
sb4 err_code = 0;
OCIErrorGet(
error_handle.get(),
(ub4)1,
0,
&err_code,
err_buf,
sizeof(err_buf),
(ub4)OCI_HTYPE_ERROR);
std::cerr << err_buf << "', error code = " << err_code << ", row errors: ";
for(const ub2* cur = ERROR_BUFFER_1;
cur < ERROR_BUFFER_1 + 1024; ++cur)
if(*cur)
std::cerr << "#" << (cur - ERROR_BUFFER_1) << ": " <<
*cur << std::endl;
ub4 fetched_count = 0;
if((result = OCIAttrGet (
stmt_handle.get(),
OCI_HTYPE_STMT,
&fetched_count,
0,
OCI_ATTR_ROW_COUNT,
error_handle.get())) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIAttrGet", result, error_handle.get());
all_fetched_count += fetched_count;
if(fetched_count > 0)
for(unsigned long i = 0; i < fetched_count - 1; ++i)
ub4 lob_size;
while((result = OCILobGetLength(
svc_context_handle.get(),
error_handle.get(),
FETCH_BUFFER_1[i],
&lob_size)) == OCI_STILL_EXECUTING)
if(result != OCI_SUCCESS)
throw_oci_error(FUN, "OCILobGetLength", result, error_handle.get());
std::cout << "#" << i << ": ind = " << (unsigned long)IND_BUFFER_1[i] <<
", len = " << lob_size << std::endl;
if(fetched_count - prev_fetched < FETCH_COUNT)
break;
prev_fetched = fetched_count;
clear_blob_buf(
FETCH_BUFFER_1,
sizeof(OCILobLocator*));
while((result = OCIStmtFetch(
stmt_handle.get(),
error_handle.get(),
0,
OCI_FETCH_NEXT,
OCI_DEFAULT)) == OCI_STILL_EXECUTING
disconnect(
environment_handle.get(),
error_handle.get(),
server_handle.get(),
session_handle.get(),
svc_context_handle.get());
return 0;
int execute_update(
const char* db,
const char* user,
const char* password)
static const char* FUN = "execute_update()";
OCIHandlePtr<OCIError, OCI_HTYPE_ERROR> error_handle;
OCIHandlePtr<OCIServer, OCI_HTYPE_SERVER> server_handle;
OCIHandlePtr<OCISession, OCI_HTYPE_SESSION> session_handle;
OCIHandlePtr<OCISvcCtx, OCI_HTYPE_SVCCTX> svc_context_handle;
connect(
environment_handle.get(),
db,
user,
password,
error_handle,
server_handle,
session_handle,
svc_context_handle);
OCIHandlePtr<OCIStmt, OCI_HTYPE_STMT> stmt_handle;
for(int i = 0; i < 1000; ++i)
sword result;
if((result = OCIHandleAlloc(
environment_handle.get(),
(void**)&stmt_handle.fill(),
OCI_HTYPE_STMT,
0,
0)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIHandleAlloc", result, error_handle.get());
std::ostringstream sql;
std::string str;
std::string et("\xEB\xB2\x88");
unsigned long rep = ::rand() % 500 + 1;
str.reserve(rep*et.size());
for(unsigned long ei = 0; ei < rep; ++ei)
str.append(et);
sql << "BEGIN " <<
"UPDATE ADSERVERTEST_BLOB SET text = "
"utl_raw.cast_to_raw('" << str << "') "
"WHERE id = " << i <<
"END;";
if((result = OCIStmtPrepare(
stmt_handle.get(),
error_handle.get(),
(text*)sql.str().c_str(),
sql.str().length(),
OCI_NTV_SYNTAX,
OCI_DEFAULT)) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIStmtPrepare", result, error_handle.get());
while((result = OCIStmtExecute(
svc_context_handle.get(),
stmt_handle.get(),
error_handle.get(),
1,
0,
0,
0,
OCI_DEFAULT)) != OCI_SUCCESS)
if(result != OCI_STILL_EXECUTING)
throw_oci_error(FUN, "OCIStmtExecute", result, error_handle.get());
disconnect(
environment_handle.get(),
error_handle.get(),
server_handle.get(),
session_handle.get(),
svc_context_handle.get());
return 0;
void* select_thread(void* ctx)
while(true)
execute_select(
"//oraclept.ocslab.com/addbpt.ocslab.com",
"bs_unittest_4",
"adserver");
// std::cout << "select finished" << std::endl;
return ctx;
void* update_thread(void* ctx)
while(true)
execute_update(
"//oraclept.ocslab.com/addbpt.ocslab.com",
"bs_unittest_4",
"adserver");
// std::cout << "update finished" << std::endl;
return ctx;
int main()
static const char* FUN = "main()";
sword result;
// allocate an environment handle
if((result = OCIEnvCreate(
&environment_handle.fill(),
OCI_OBJECT | OCI_THREADED,
0, // context
0, // malloc
0, // realloc
0, // free
0, // extra memory to allocate
0) // pointer to user-memory
) != OCI_SUCCESS)
throw_oci_error(FUN, "OCIEnvCreate", result, 0);
pthread_t th1, th2;
pthread_create(&th1, 0, select_thread, 0);
pthread_create(&th2, 0, update_thread, 0);
pthread_join(th1, 0);
pthread_join(th2, 0);
return 0;
Edited by: user13011391 on 20.04.2010 5:50
Edited by: user13011391 on 20.04.2010 6:00
Edited by: user13011391 on 20.04.2010 6:15 -
Adpreclone.pl Non-interactive Mode
Hi All,
want to automate backup of APPL tier
To do that it is required to run adpreclone.pl with non-interactive mode i.e. It will not ask for any password when it will run through shell script.
Or something like perl adpreclone.pl appsTier pwd=<>
Is there is any other way to do that?
Please advice.
Thanks-
P966726 wrote:
Hi All,
want to automate backup of APPL tier
To do that it is required to run adpreclone.pl with non-interactive mode i.e. It will not ask for any password when it will run through shell script.
Or something like perl adpreclone.pl appsTier pwd=<>
Is there is any other way to do that?
Please advice.
Thanks-
PPlease see old threads -- https://forums.oracle.com/forums/search.jspa?threadID=&q=Automate+AND+Clone&objID=c3&dateRange=all&userID=&numResults=15&rankBy=10001
Thanks,
Hussein -
Hello Techies,
How to set sockets in the non-blocking mode and what is the main use of setting sockets in non-blocking mode.
regards,
Ramu.Hello Techies,
Thanks for u r replies,
Finally i had understood how to use nio. But the problem is it is going into infinite loop. Here is my code.
package networking;
import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.Iterator;
public class testSocketChannel {
* @param args
public static ByteBuffer buf ;
public static SocketChannel clientChannel;
public static void main(String[] args) {
// TODO Auto-generated method stub
try
Selector selector = Selector.open();
clientChannel = SocketChannel.open();
clientChannel.configureBlocking(false);
// Send a connection request to the server; this method is non-blocking
clientChannel.connect(new InetSocketAddress("localhost",90));
clientChannel.register(selector,clientChannel.validOps());
// Wait for events
while (true)
try {
// Wait for an event
selector.select();
} catch (IOException e) {
// Handle error with selector
//break;
// Get list of selection keys with pending events
Iterator it = selector.selectedKeys().iterator();
// Process each key at a time
//while (it.hasNext())
for(int i = 0;i<selector.selectedKeys().size();i++)
// Get the selection key
SelectionKey selKey = (SelectionKey)it.next();
// Remove it from the list to indicate that it is being processed
it.remove();
try
// processSelectionKey(selKey);
if (selKey.isValid() && selKey.isConnectable()) {
// Get channel with connection request
SocketChannel sChannel = (SocketChannel)selKey.channel();
boolean success = sChannel.finishConnect();
if (!success) {
// An error occurred; handle it
// Unregister the channel with this selector
selKey.cancel();
if (selKey.isValid() && selKey.isReadable()) {
// Get channel with bytes to read
clientChannel = (SocketChannel)selKey.channel();
System.out.println("INSIDE reading");
// See e174 Reading from a SocketChannel
// Clear the buffer and read bytes from socket
// Clear the buffer and read bytes from socket
// ByteBuffer byteBuffer = ByteBuffer.allocate( BUFSIZE );
buf = ByteBuffer.allocateDirect(1024);
int nbytes = clientChannel.read( buf );
buf.flip();
Charset charset = Charset.forName( "us-ascii" );
CharsetDecoder decoder = charset.newDecoder();
CharBuffer charBuffer = decoder.decode( buf );
String result = charBuffer.toString();
if (selKey.isValid() && selKey.isWritable()) {
// Get channel that's ready for more bytes
//SocketChannel sChannel = (SocketChannel)selKey.channel();
System.out.println("INSIDE writting");
// See e175 Writing to a SocketChannel
String message = "hi";
buf = ByteBuffer.wrap( message.getBytes() );
int nbytes = clientChannel.write( buf );
System.out.println( "Wrote " + nbytes + " to channel." );
catch (IOException e) {
// TODO: handle exception
System.out.println("IOException"+e.getMessage());
catch (IOException ioe) {
// TODO: handle exception
System.out.println("IOException"+ioe.getMessage());
}How to stop this infinite loop.
Need quick replies.
Ramu -
ORA-03118 two-task error while doing a non blocking OCI call
Hi,
I have an application that runs on Linux and uses OCI API (version 8.1.6).
If I do the following in non blocking mode after polling about
70 times I get the error:
ORA-03118: two-task coroutine has invalid state
do {
call_cnt++;
rtc = OCIStmtFetch(stmtptr->stmt, oracle_err, 1, OCI_FETCH_NEXT,
OCI_DEFAULT);
} while (rtc == OCI_STILL_EXECUTING);
This doesn't happen all the time but it happens most often on big selects.
Does anyone have any idea what is happening here?
I have searched for related information but have come up dry. If anyone
knows anything or maybe a better place to ask this question please tell me.
Thanks,
Barry
nullAsk your basis guys to increase the table space...
check this thread...
[Error : DBIF_RSQL_SQL_ERROR;
--- Thanks... -
I have been getting more than my fair share of grey hairs the past few days because of this. Over the past few months this almost never happened. Lately, after a seemingly minor change to some serial communications code, hardly a single build works without throwing errors like this:
#OSVers: 6.3
#OSBuild: Jun 6 2014, 09:14:16
#AppName: /c/ni-rt/system/lvrt.out
#Version: 14.0
#AppKind: AppLib
#AppModDate:
InitExecSystem() call to GetCurrProcessNumProcessors() reports: 1 processors
InitExecSystem() call to GetNumProcessors() reports: 1 processors
InitExecSystem() will use: 1 processors
starting LabVIEW Execution System 306708506 Thread 0 , capacity: 1 at [3507679466.00933790, (19:24:26.009337710 2015:02:24)]
starting LabVIEW Execution System 306708507 Thread 0 , capacity: 1 at [3507679470.59560204, (19:24:30.595601929 2015:02:24)]
starting LabVIEW Execution System 2 Thread 0 , capacity: 24 at [3507679481.25993776, (19:24:41.259937648 2015:02:24)]
starting LabVIEW Execution System 2 Thread 1 , capacity: 24 at [3507679481.25993776, (19:24:41.259937648 2015:02:24)]
starting LabVIEW Execution System 2 Thread 2 , capacity: 24 at [3507679481.25993776, (19:24:41.259937648 2015:02:24)]
starting LabVIEW Execution System 2 Thread 3 , capacity: 24 at [3507679481.25993776, (19:24:41.259937648 2015:02:24)]
Thread consumption suspected: 3 Try starting 4 threads
starting LabVIEW Execution System 2 Thread 4 , capacity: 24 at [3507679515.59324312, (19:25:15.593243004 2015:02:24)]
starting LabVIEW Execution System 2 Thread 5 , capacity: 24 at [3507679515.59324312, (19:25:15.593243004 2015:02:24)]
starting LabVIEW Execution System 2 Thread 6 , capacity: 24 at [3507679515.59324312, (19:25:15.593243004 2015:02:24)]
starting LabVIEW Execution System 2 Thread 7 , capacity: 24 at [3507679515.59324312, (19:25:15.593243004 2015:02:24)]
Thread consumption suspected: 8 Try starting 1 threads
starting LabVIEW Execution System 2 Thread 8 , capacity: 24 at [3507679515.73854351, (19:25:15.738543576 2015:02:24)]
and
#Date: TUE, FEB 24, 2015 04:47:22 PM
#OSName: VxWorks
#OSVers: 6.3
#OSBuild: Jun 6 2014, 09:14:16
#AppName: /c/ni-rt/system/lvrt.out
#Version: 14.0
#AppKind: AppLib
#AppModDate:
InitExecSystem() call to GetCurrProcessNumProcessors() reports: 1 processors
InitExecSystem() call to GetNumProcessors() reports: 1 processors
InitExecSystem() will use: 1 processors
starting LabVIEW Execution System 306708506 Thread 0 , capacity: 1 at [3507670087.84041262, (16:48:07.840412710 2015:02:24)]
starting LabVIEW Execution System 306708507 Thread 0 , capacity: 1 at [3507670092.45153570, (16:48:12.451535843 2015:02:24)]
starting LabVIEW Execution System 2 Thread 0 , capacity: 24 at [3507670103.11840487, (16:48:23.118404925 2015:02:24)]
starting LabVIEW Execution System 2 Thread 1 , capacity: 24 at [3507670103.11840487, (16:48:23.118404925 2015:02:24)]
starting LabVIEW Execution System 2 Thread 2 , capacity: 24 at [3507670103.11840487, (16:48:23.118404925 2015:02:24)]
starting LabVIEW Execution System 2 Thread 3 , capacity: 24 at [3507670103.11840487, (16:48:23.118404925 2015:02:24)]
VI_BROKEN (0): [VI "NC serial comms protocol.lvlibet Lower Temperature Limit.vi" (0x04667310)]
VirtualInstrument:etOrClearBadVILibrary - now VI is bad on [VI "NC serial comms protocol.lvlibet Lower Temperature Limit.vi" (0x04667310)]
this->flags=33563136, compilerError=6
VI_BROKEN (0): [VI "Heater Control HAL.lvclass:Write Heater Control Active.vi" (0x058c4e98)]
VirtualInstrument:etOrClearBadVILibrary - now VI is bad on [VI "Heater Control HAL.lvclass:Write Heater Control Active.vi" (0x058c4e98)]
this->flags=50340352, compilerError=6
VI_BROKEN (0): [VI "NI_LVConfig.lvlibave Config File.vi" (0x047b7e90)]
VirtualInstrument:etOrClearBadVILibrary - now VI is bad on [VI "NI_LVConfig.lvlibave Config File.vi" (0x047b7e90)]
this->flags=33563136, compilerError=6
and so on.
This is using a cRIO 9074 running CompactRIO recommended software set 14.0.1 .
These errors happen right at startup. Memory use is steady in interactive mode, about 20 MB contiguous memory is unallocated out of 128 MB. I have taken pains to prevent allocation and follow cRIO besta practices non concatenated strings array building in loops etc). CPU is 50-60% when running interactive mode.
Really at my whit's end here, I have tried the various combination of enabling / disabling debugging in the RTEXE, disconnecting typedefs etc. I have not noticed a pattern.
Regards,
MarkCGHello MarkCG,
What minor changes did you make to the serial communication code? Posting the VI or a screenshot of the VI with the modifications which caused the RTEXE to stop functioning could be useful to troubleshoot the issue.
Regards,
J_Bou -
I'm trying to learn how to use non-blocking socket channles, but I haven't found much info (nor luck) so far.
To learn, I'm building a server and a client. The server accepts input from the clients and process it in only one thread. The clients should send Objects to the server, and the server process them and return the result also as an Object. For this, I'm trying to use ObjectOutputStream and ObjectInputStream.
The problem I don't know how to solve is that the SocketChannel is in non-bolcking mode, so I can't use their input/output streams (I get a IllegalBlockingModeException). In the server process loop I can reconfigure the SocketChannel to blocking mode to be able to read the Object, but I can't configure it to non-blocking mode again because I get a CancelledKeyException.
Does anyone know how to work with InputStreams and non-blocking channels? Or where to find more info about it?
Here are the relevant part of the server code:
Set ready = selector.selectedKeys();
Iterator i = ready.iterator();
while (i.hasNext()) {
try {
SelectionKey sk = i.next();
i.remove();
if (sk.isAcceptable()) {
ServerSocketChannel ssc = (ServerSocketChannel)sk.channel();
SocketChannel sc = ssc.accept();
sc.configureBlocking(false);
sc.register(selector, SelectionKey.OP_READ);
} else if (sk.isReadable()) {
SocketChannel sc = (SocketChannel)sk.channel();
// PROBLEM: If the channel is in non-blocking mode
// I cannot use InputStreams
sk.cancel();
sc.configureBlocking(true);
// Read the object sent by the client
ObjectInputStream in = new ObjectInputStream(Channels.newInputStream(sc));
Object o = in.readObject();
// PROBLEM: Can't put the channel back to non-blocking mode
sc.configureBlocking(false);
sc.register(selector, SelectionKey.OP_READ); // CancelledKeyException
} catch (...){
}In my client, this is working fine:
ObjectOutputStream oos = null;
ObjectInputStream ois = null;
for (int i = 0; i < 30000; i++) {
oos = new ObjectOutputStream(sc.socket().getOutputStream());
oos.writeObject(object);
oos.flush();
ois = new ObjectInputStream(sc.socket().getInputStream());
Object o = ois.readObject();
}But trying to do it like this throws a StreamCorruptedException at the server side.
ObjectOutputStream oos = new ObjectOutputStream(sc.socket().getOutputStream());
ObjectInputStream ois = new ObjectInputStream(sc.socket().getInputStream());
for (int i = 0; i < 30000; i++) {
oos.writeObject(object);
oos.flush();
Object o = ois.readObject();
}Do you know why? -
How to handle write errors in non blocking sockets
Hi,
I'm using sockets registered with a Selector for read operations. I've seen code examples that put the SocketChannel in non blocking mode before registering it with the selector, and in fact not doing so would cause an IllegalBlockingModeException to be thrown.
My problem is that I can't handle write errors. The call to write() returns inmediately without throwing any exception. Even worse, when the network timeout expires the selector wakes up and I get an exception on read(). So I can't tell the difference between a real read error and a write error.
What can I do? Is there a magic method I haven't heard about?
Thanksejp wrote:
OK, so what happens is this: you write from your ByteBuffer; if there is room in the socket send buffer, the data is transferred and the transfer count is returned. (If there isn''t, the write returns zero and nothing has happened.) Your application code then continues. Meanwhile TCP is trying to send the data in the send buffer and get an ACK from the peer. If the peer is down as per your test, eventually those write attempts will time out. You will then get a connection reset exception on the next read or write.
Even worse, when the network timeout expires the selector wakes upCorrect, to tell you there is an error condition pending. This is good, not bad.You're right. This way my program can know that something happened.
But I still don't understand what the difference between a failed write() and a failed read() is. I mean, the error condition may appear during a send attempt, or it may appear after sending. In both cases I get an error when trying to read. How can my program know if data have been received by the other end?
Do I have to implement ACK messages in the application level protocol??? It'd be nice if TCP could do this for me... -
Non-blocking SocketChannel and close - huh?
It looks like closing a socketchannel that is in non-blocking mode can result in a dead drop of the connection, with some bytes that have already been sent and accepted (as in, 'consumed' from the buffer) being completely dropped.
In fact, I'm generally confused: Actual C non-blocking code has a similar setup for 'close' as you can see in SocketChannel's OP_CONNECT behaviour - just because you want to connect the socket doesn't mean it magically happends without blocking. Wait for a ready flag, then try again.
It should work the same way with close (you try to close, but it may not be possible without blocking).
Is this a huge gaping bug that no one quite figured out just yet, or did I miss something? I loathe to turn on linger, as that's just a crapshoot (you never know if it actually gets through. You could run into funny surprises once the server gets a bit busy. I'd rather not) and tends to cause massive leaks on linux, at least according to some google searches.
There seems to be slightly better performance (in that I have always received all data sofar) if I close the socket instead of the channel (socketChannel.socket().close() instead of socketChannel.close()) - but this has been a random attempt at 'making it work', and I can't find any documentation that backs up that this will DEFINITELY not lose any information without letting me know somehow. That still sounds impossible with this approach.Actual C non-blocking code has a similar setup for
'close' as you can see in SocketChannel's
OP_CONNECT behaviour ...No it doesn't. I don't know what you mean by this.
Closing a socket is asynchronous, but it shouldn't lose any data - if the data can be delivered it will be, followed by the FIN. You don't know when it is delivered, and you don't get to hear about any errors such as an RST coming from the other end, say if it decided to close before reading all the data, or if some intermediate router hung you up.
I'm wondering if you are really dealing with all the short write and zero length write possibilities, i.e. whether the data isn't really still in your output buffer. Don't wish to teach you to suck eggs but there are some subtleties here.
Setting a positive linger timeout doesn't really help because Java doesn't tell you if the timeout expired. (I only asked for this about four years ago). You get to wait while any pending data is delivered, but you still have to guess about whether it all went or the timeout expired, and the behaviour after the timeout expires is platform-dependent: some (Windows) issue an RST, others (Unix) keep trying.
Blocking or non-blocking mode shouldn't make any difference to this (except that Linux will block on a positive linger timeout even in non-blocking mode, which is wrong), and whether you close the channel or the socket is immaterial as one calls the other anyway.
The reason why OP_CONNECT is different in blocking/non-blocking modes is that in blocking mode it won't return until the SYN-ACK is received, while in non-blocking mode it just sends the SYN and relies on you calling connect() again (at the C level) to collect the SYN-ACK, or not - this is what finishConnect() tells you.
tends to cause massive leaks on linux, at least
according to some google searchesIt can't, unless you are referring to the Helix client thing, which appears to be just a badly designed C++ class library with, for some reason, its own linger implementation outside the kernel.
Maybe you are looking for
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