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"Awesome response, as usual. It is a sincere and refreshing pleasure to do business with DTN, compared to your competition." - Comment from Ryan
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20 Most recent posts:
IQFeed Developer Support » Failure under recent version of Wine Jan 10, 2021 04:57 PM (Total replies: 4)

Follow up: Fedora recently upgraded to Wine 6.0, and IQConnect seems to be working again. I'll let you know if the problem reappears.


Back to normal performance levels today.


Hi, Gary. Thanks for the update!

Just to clarify, is the rate limit per-connection, or per-IP-address (or some other key)? Since I have multiple threads issuing requests on separate connections, there are conditions under which more than 50 requests could be issued over the course of a second for all the connections in aggregate, though not for any individual connection.

I implemented a request-rate limiter last week, just in case. Maybe the observed slowdown was unrelated to the changes at your end. We'll see what happens today.


Following up with some data from my logs. Minor correction; I see there are 7 active threads, not 8; the code says I chose that to stay under half of IQFeed's suggested limit of 15.

On 2020-12-22, my history fetch showed mean latency (time from sending request to arrival of first data record) of 0.22 seconds. Min was about 0.1, median about 0.24, max about 0.6. Mean data transfer time (from arrival of first data record to arrival of last data record) was 0.09 seconds. Min was 0, median about 0.04, max about 10.2.

So, some equities generate a lot of data. For data transfer alone, the best average completion rate I could ever achieve would be about 80 requests per second. On the other hand, some equities trade very thinly, so their transfer time is essentially zero, and the peak request rate could be extremely high. This is what I mentioned in my earlier postings.

On 2020-12-23, the mean latency was 1.22 seconds (!); min 0.4, median 1.0, max 3.5. Mean transfer time was 1.9; min 0, median 0.04, max 118 (!!!).

Things got really slow on 2020-12-23 for both latency and throughput. Maybe it was just an odd coincidence that this happened the same day we received notice of the new rate limiting algorithm. I'm curious to see what happens tomorrow.


Hi, Mathieu. I don't object to showing you the code (other than embarrassment because some is old and crufty), but it's straightforward. This is a C++ socket-based app that has existed for more than a decade being run on a capable modern desktop machine with an AT&T gigabit fiber connection and no recent changes to the code or to its environment, so an overnight factor-of-six slowdown suggests to me that the new rate-limiting on the feed might be having more effect than intended.

Until the new rate-limiting started, I was averaging 12 completed requests per second, which seems pretty reasonable to me. Some loss of performance is caused by round-trip latency (for simplicity and error recovery, as well as compliance with previous IQFeed policy, each thread keeps only one request in flight at a time). But I suspect the main reason for the low average rate is that for some equities, an entire day worth of ticks takes a significant amount of time to prepare, transmit, and process. It's not just a matter of the maximum rate at which the app is allowed to issue history requests.


Hi, Gary. I'm confused about the purpose and implementation of the new limit.

Each day after the main trading session (at 7PM Eastern) I fetch tick history for all the symbols I'm screening. Currently there are 4090 of them.

My first reaction on hearing about the new rate limit was "That's fine; I'm OK with a lower limit, though I doubt I'm hitting 50 requests per second as it is." I run 8 threads, each of which performs history requests sequentially, so there are at most 8 requests in flight at any given time, and it takes a while for each one to complete and a new one to be issued. (The data has to be received, reformatted, compressed, and written to disk before a new request is issued.)

Yesterday, for example, the history fetch took 339 seconds, for an average of about 12 completed requests per second.

Today the history fetch took 2031 seconds, for an average of 2 completed requests per second. Wow; that's quite a change. It's slower than the days when I had a 6Mbps DSL line.

My best guess is that the majority of history requests finish quickly, so they're hitting the rate limit and are being delayed by as much as a factor of 6. However, a fair number of requests take a long time to finish, which drags down the average way below the nominal rate limit. High peak rate, low average rate.

So I'm curious as to whether your intent is to limit the rate at which requests are initiated, or the bandwidth demand on the servers. If the latter, the current approach may be too drastic; my connection is idle more than 80% of the time.

IQFeed Developer Support » Failure under recent version of Wine Dec 14, 2020 06:36 PM (Total replies: 4)

Thanks! If they need more information, I'll be happy to help debug.

IQFeed Developer Support » Failure under recent version of Wine Dec 10, 2020 06:44 PM (Total replies: 4)

FYI, I've downgraded Wine to version 5.5 (the most recent older version available in the Fedora 32 repositories) and everything works correctly. This will keep me going for a while, but eventually I'll need a more solid fix.

IQFeed Developer Support » Failure under recent version of Wine Dec 7, 2020 10:41 AM (Total replies: 4)

Over the weekend I did a routine OS (Fedora 32) update, and Wine version 5.22 was installed. Now iqconnect won't launch. I've attached the backtrace from attempting to run diagnostics.exe.

Any suggestions for tracking down the problem?

Thanks!
Allen

IQFeed Developer Support » API on Linux Apr 15, 2020 05:50 PM (Total replies: 10)

@karthikkrishan: I start my monitoring app when my machine boots. That can be done manually, by a command in rc.local, or by a systemd service. (I haven't done the last, though the configuration process looks pretty reasonable.) The monitor runs until the system shuts down, though it can be killed and restarted manually.

The monitor can be commanded to remain active 24/7, which is useful during development, but normally it sleeps while the market is closed and wakes up shortly before the open. It starts up IQConnect by forking and execing
/usr/bin/wine /home/home-dir/.wine/drive_c/Program Files/DTN/IQFeed/iqconnect.exe -product product-name -version version-number -login iqfeed-username -password iqfeed-password -autoconnect 
Then it opens the streaming port and communicates with the usual protocol.

The monitor has an exponential-fallback procedure to attempt reconnection in case the connection is lost, but I'll skip that for now. It's not clear to me that it's needed to the extent that it used to be.

At the end of the day the monitor automatically forks and execs other apps to collect the day's history and fundamentals. Multiple connections work fine; for example, I usually do history fetch with seven clients running in parallel.

During the day I start my other apps manually for analysis and trading. They just assume IQConnect is running, connect to the appropriate port(s), and go. Obviously you could do something more sophisticated, but I haven't found it necessary, and having a single "master" process to handle error conditions simplified things when I was writing the code years ago.

At the end of the trading day the monitor closes the last connection and after a while iqconnect.exe exits. Just to make sure everything stays sane for the next day, the monitor shoots it down with
killall iqconnect.exe
if it's hanging around unexpectedly.

So that's an overview of how it all works. IQFeed is a stronger, more reliable product than it was when I started this long ago, so you can probably get by with a simpler infrastructure nowadays.

IQFeed Developer Support » API on Linux Apr 13, 2020 07:30 PM (Total replies: 10)

I've been using IQFeed under Wine on Fedora successfully for a very long time. My usage pattern is simple, though -- a "monitor" app starts up before the opening session and stays open until the close, while apps performing specialized functions connect as needed during the day. The monitor app is the only one that tracks and manages the status of the service.

I'd certainly like a native API, and in the past have offered to help out with an implementation, but I understand the need to keep the support load under control.

IQFeed Developer Support » Consuming IQFeed APIs via C++ on Linux Nov 17, 2018 01:11 AM (Total replies: 16)

My 64-bit app just executes a 32-bit stub that starts IQConnect. Yes, it's stone age.

IQFeed Developer Support » Consuming IQFeed APIs via C++ on Linux Nov 16, 2018 05:40 PM (Total replies: 16)

Thanks for the clarification!

Hopefully Tim or Steve will correct me if I'm wrong, but my understanding is that it's not possible to run IQFeed completely headless. You can configure things so that the username and password are provided automatically, without creating a dialog window. (That's the way my setup works.) However, as you noticed, there will still be an applet in the tray for the duration of the run.

The MIT-SHM extension is used by GUI toolkits to speed up the transfer of images from the application or toolkit to the X server. I've forgotten which toolkit IQConnect uses (maybe it's Qt?), but apparently it attempts to initialize or use the extension.

You can see from the xdpyinfo output after the line "number of extensions: 23" that MIT-SHM is not among the extensions provided by Xming.

I forgot to mention that you should export the environment variables after setting them. Did you do that anyway?

You're correct that there is no Linux executable for IQConnect; we have to use Wine.

You should be able to traceroute from your Linux box to your Windows box even though the Windows box isn't directly accessible from the Internet. It should still be directly accessible from your Linux box. If it's not (for example, because a firewall setting prevents it), that could account for the ICMP failure.

IQFeed Developer Support » Consuming IQFeed APIs via C++ on Linux Nov 15, 2018 10:32 AM (Total replies: 16)

I haven't looked into this in any level of detail, but it appears there are a couple of problems.

First, running remotely (over ssh?) means that the MIT-SHM extension won't be usable. It's a shared-memory image transfer extension for improved local performance, and that doesn't work over the net. I suppose it's also possible that Xming doesn't support it; try the
xdpyinfo
command to see if MIT-SHM is one of the supported extensions.

A quick Google suggests that setting environment variables to disable use of the extension might help. Before running IQConnect, try this:
QT_X11_NO_MITSHM=1
_X11_NO_MITSHM=1
_MITSHM=0


The ping failure is something different, but at the moment I'm not sure what. Firewall issue? If you
traceroute
from your Debian machine to your Windows machine, what happens?

IQFeed Developer Support » Consuming IQFeed APIs via C++ on Linux Nov 13, 2018 03:13 PM (Total replies: 16)

Not able to reproduce here. The shutdown procedure for my app must differ from yours.

IQFeed Developer Support » Consuming IQFeed APIs via C++ on Linux Nov 12, 2018 11:51 AM (Total replies: 16)

I haven't captured the Wine log file in a while, so at the moment I can't check for that. I've enabled logging to see if it crops up when my app exits later today.

That said, I expect Steve is right and this is just a consequence of the normal shutdown procedure when there are no clients.

I run my client with regular user privileges; there's no need to run as root.

IQFeed Developer Support » Consuming IQFeed APIs via C++ on Linux Aug 13, 2018 11:14 AM (Total replies: 16)

Apologies for the late reply; I've been on vacation.

I've been running IQFeed with Wine on Linux for years. Only once (back in 2015) have I had a significant problem, and Tim worked closely with me to solve it.


I don't have any information about the "Ping Failed" line. However, the rest of the log indicates that IQConnect started successfully but no app connected to the administration port (9300). IQConnect eventually shuts down if there are no connections to that port.

Before IQConnect shuts down, can you run one of the other IQFeed apps to see if it works properly? If so, the next place to look is in your app. If not, there are other possibilities; a firewall issue, for example.

One other thing occurs to me. You might be having trouble running IQConnect if Wine is in 64-bit mode. This happened to me in the past, and I worked around it, but I don't know if it's still an issue. To try the workaround, set the environment variable WINEARCH to "win32" before running IQConnect.


Install Wine. Then download the IQFeed client and install it (I used "wine iqfeed_client_5_2_5_0.exe"; just substitute the correct filename for the client that you downloaded).

You can start the IQFeed server (IQConnect) manually, or your application can start it automatically by executing the appropriate command with execl() or system(). The command will be something like "/usr/bin/wine /YOUR_HOME_DIRECTORY/.wine/drive_c/Program Files/DTN/IQFeed/iqconnect.exe -product YOUR_REGISTERED_PRODUCT_NAME -version YOUR_REGISTERED_PRODUCT_VERSION -login YOUR_LOGIN_ID -password YOUR_PASSWORD -autoconnect".

Once IQConnect has started your app can connect to the TCP ports and issue commands as described in the Developer Documentation.

Data and Content Support » Symbol Guide Changelist Is Stuck May 5, 2017 07:02 PM (Total replies: 1)

On http://iqfeed.net/symbolguide, the "U. S. STOCKS - ADDITIONS" page seems not to have been updated since April 21st.


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