I am quite new to C3P0 & was reading some of its properties here : https://www.mchange.com/projects/c3p0/#unreturnedConnectionTimeout
I have a simple question about C3P0 from those who have used it - If i set both minPoolSize = 1 & maxPoolSize = 1 & maxConnectionAge = 30 secs.
Will C3P0 connection destroy the connection after 30 secs & acquire a new connection Or
It will keep the same connection open?
Most probably, yes, but to know for sure, you will probably have to debug the code. You could try to set a break point in the connection constructor of your driver and let the timeout happen. Observe that the break point is hit to verify that it in fact works like that.
Related
I have started to work on a Spring WebFlux and R2DBC project. Mainly, my code works fine.
But after some elements I am receiving this warning
r2dbc.mssql.client.ReactorNettyClient : Connection has been closed by peer
after this warning I am getting this exception and normally program stops to read from Flux which source is R2DBC driver.
ReactorNettyClient$MssqlConnectionClosedException: Connection unexpectedly closed
My main pipeline like this;
Sinks.Empty<Void> completionSink = Sinks.empty();
Flux<Event> events = service.getPairs(
taskProperties.A,
taskProperties.B);
events
.flatMap(some operation)
.doOnComplete(() -> {
log.info("Finished Job");
completionSink.emitEmpty(Sinks.EmitFailureHandler.FAIL_FAST);
})
.subscribe();
completionSink.asMono().block();
After run, flatMap requesting 256 element as a default, then after fetching trying to request(1) for next signal.
At somewhere between 280. and 320. element it is getting above error. It is not idempotent, sometimes it reads 280 element sometimes it is reading 303, 315 etc.
I think it is about network maybe? But not sure and cannot find the reason. Do I need a pool or something different?
Sorry if I missed anything, in case you want I will try to update here.
Thank you in advance
I have tried to change request size of flatMap to unbounded, adding scheduler, default r2dbc pool but for now I don't have any clue.
I asked how to make TCP server that send data all the time in here: Julia TCP select and it works great. I now I have new problem, so I thought to start new conversation.
I did this kind of connection like on the picture:
So Sender sends sometimes something to server 1 and server 1 reads it and updates what to send to server 2 and Server 2 calculates numbers and communicates with C program.
Here is my server 1 code:
notwaiting = true
message = zeros(10,14)
server = listen(5001)
connection = connect(5003)
while true
if notwaiting
notwaiting = false
# Runs accept async (does not block the main thread)
#async begin
sock = accept(server)
reply= read(sock, Float64, 11)
message[:,convert(Int64,reply[1])] = reply[2:11]
write(connection,reshape(message,140))
global notwaiting = true
end
end
write(connection,reshape(message,140))
if message[1,1] == -1.0
close(connection)
close(server)
break
end
sleep(0.01) # slow down the loop
end
Sender is:
Connection2= connect(5001)
message = [2.0,0.0,0.0,0.0,0.0,1.0,0.0,0.0,0.0,0.0,0.0]
write(Connection2,message)
close(Connection2)
And server 2 is like this:
function Server2_connection()
println("Waiting for connection")
server2 = listen(5003)
conn_2 = accept(server2)
while isopen(conn_2)
try
message_server2 = round(read(conn_2,Float64,140),3)
ins_matrix = reshape(message_server2[1:140],10,14)
catch e
println("caught an error $e")
break
end
end
println("Connection closed")
close(conn)
close(server)
end
The problem is that everything together is really heavy. I mean that I can send 2 messages from sender and everything is running really slow. I can run the whole thing 10-15s and then it freezes. All the connections work, but really slowly. My question is am I missing something or have something that makes the servers really slow? How can I code this better way?
I don't have anymore problem with slowness. I got help from julia-users google forum and on of them(Tanmay K. Mohapatra) wrote better code for same purpose: https://gist.github.com/tanmaykm/c2ab61a52cc5afa0e54fe61905a48ef1 It works
same way.
One problem with both codes is that they don't close connections properly. If server 2 goes down, the server 1 gets writing error and server 1 stays in listen mode.
Other ways it works. Thanks to Tanmay!
Edit: found the slower....the thing what should slow things down, did it. The sleep command did slow things down, but it slowed down more than I expected. If I had sleep variable 0.001 seconds, it will slow down the whole system like 0.014s. So I removed sleep command and it works fine.
I tried setting connectTimeoutMS and socketTimeoutMS to a low value but it still takes about 20 seconds before my script times out. Am I not using the options correctly? I want the script to exit after 5 seconds.
def init_mongo():
mongo_connection = MongoClient('%s' %MONGO_SERVER, connectTimeoutMS=5000, socketTimeoutMS=5000)
if mongo_connection is None:
return
try:
<code>
except:
<code>
So if anyone comes across this later, I was using the wrong option.
What I was looking for is serverSelectionTimeoutMS
The web page:
https://api.mongodb.com/python/current/api/pymongo/mongo_client.html
says:
connectTimeoutMS: (integer or None) Controls how long (in milliseconds) the driver will wait during server monitoring when connecting a new socket to a server before concluding the server is unavailable. Defaults to 20000 (20 seconds)
(Where "server monitoring" is undefined)
So what? Is connectTimeoutMS sort of like a decoy to keep out the amateurs (like me)
I recently patched my copy of GStreamer 0.10.36 to time out the tcpclientsink if the network connection is switched between wired/wireless (More information at Method to Cancel/Abort GStreamer tcpclientsink Timeout). It's a simple change. I just added the following to the gst_tcp_client_sink_start() function of gsttcpclientsink.c:
struct timeval timeout;
timeout.tv_sec = 60;
timeout.tv_usec = 0;
...
setsockopt (this->sock_fd.fd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout, sizeof(timeout));
The strange thing is that the actual timeout (measured by wall clock time) is always double the value I set. If I disrupt the network connection with the timeout set to 60 seconds, it will take 120 seconds for GStreamer/socket to abort. If I set the timeout to 30 seconds, it will take 60 seconds. If I set the timeout to 180 seconds, it will take 360 seconds. Is there something about sockets that I don't understand that might be causing this behavior? I'd really like to know what's going on here.
This might be a duplicate of Socket SO_RCVTIMEO Timeout is double the set value in C++/VC++
I'm pasting my answer below since I think I had a similar problem.
Pasted answer
SO_RCVTIMEO and SO_SNDTIMEO do not work on all socket operations, you should use non-blocking mode and select.
The behaviour may change on different operating system configurations.
On my system the connect timeouts after two times the value I set in SO_RCVTIMEO. A quick hack like setting SO_RCVTIMEO to x/2 before a connect and x after it works, but the proper solution is using select.
References
Discussion on this problem (read comments to answer):
https://stackoverflow.com/a/4182564/4074995
How to use select to achive the desired result:
http://beej.us/guide/bgnet/output/html/multipage/advanced.html#select
C: socket connection timeout
When the quickfix initiator reconnects at startTime (defined in config) it deletes the files with sequence number, but does not set ResetSeqNumFlag to Y, and the server replies with a Logout message with text "seq msg number to low ..."
Is there a way to set ResetSeqNumFlag = Y only for this behavior? I don`t want to reset the sequence on every log-on.
This appears to be a QuickFIX/J quirk (some might consider it a bug). If ResetOnLogon=N then no ResetSeqNumFlag=Y is sent when the session start time triggers a logon. If ResetOnLogon=Y, the ResetSeqNumFlag=Y is sent on every logon. I believe this is not a big problem in practice because participants in a FIX session typically reset their sequence numbers locally after a session ends (logically ends at the end time, not a connection disconnect).
If you want to slightly modify the source code to implement this behavior, you'd modify the quickfix.Session next() method. You could add a local flag that indicates a session has restarted (per the schedule as determined by checkSessionTime()). Pass that flag to generateLogon() and that method would use it to determine when to send ResetSeqNumFlag=Y regardless of the ResetOnLogon configuration.
I don`t want to reset the sequence on every log-on.
Then don't do it! Set ResetOnLogon=N.
At StartTime, the session will reset sequence numbers always. If ResetOnLogon=N, then they won't reset again until the next StartTime.
The initiator and acceptor should always have matching ResetOnXXX settings.
What you are asking cannot, should not be done. You start you engine with some config and then you change the config while running. If something goes wrong it will be very difficult to pinpoint what started the issue.
Instead of doing ResetSeqNumFlag = Y try adding ResetOnLogon=Y in your config for the acceptor side(that is if you have control over it) or ResetOnLogout=Y / ResetOnDisconnect=Y in your initiator config file. That would be much easier and changing config while running, is possibly not the best solution.
Your logout(disconnect can happen anytime) will happen anyways at EndTime anyways and should be easier for your application.