Data: Real-Time vs. Streaming

Discussion in 'Data Sets and Feeds' started by gordo, Feb 14, 2003.

  1. gordo


    Just wondering if anyone could tell me the difference between live real-time data and streaming data. Recently, my employment situation has changed and therefore I am using a cheaper (free) charting and data combination. As a result, (perhaps other factors as well), it seems that I just can't get a good feel for the market. Keep in mind that I have been exclusively paper trading the market for the last year, as was doing very well. These last 6 weeks, I just can't get in tune. Nearly all trades have been losers, there have been a great deal of them (read overtrading). After some thought, I began to think it might have something to do with my data source. Also, I do not have access to the futures. Most of my previous trades were done watching the morning futures and trading in the 1st 1/2hr as a result. Very frustrated and getting down on myself. Any input from you all would be appreciated.


  2. "Streaming" data is usually realtime.

    The distinction isn't between streaming and realtime, it's between streaming and a full blown datafeed like or esignal, i.e., you can only see quote data from the point in time you start reading the stream but a full datafeed seamlessly integrates the current quote stream with previous data and does its own minute bar assembly.

    Personally, can't see how anyone can trade by just looking at a streaming quote display without charts. Or if they do have charts using some freeware that can read the quote stream and assemble bars, I don't see the effectiveness of charts that only start from the time I start them.

    Guess there are those who do it this way though and more power to them, it doesn't work for me.

    Good luck.
  3. gordo



    My post may have been somewhat incomplete. I am using quotetracker as my charting package, and one of the free streaming quote packages (think it's through Scottrade). It is setup to display two days of data (today & previous) with data backfill. So I have replicated as closely I can my old Reuters display. However, it seems like it has a different feel to it than the system that I previously used (Reuters). Reuters is a premium source, I understand, maybe I' not used to my low cost setup yet.


  4. Gordo - Since I did the naming of the sites, I will try to explain.

    Many sites provide real-time data via snapshot quotes - you refresh a page, and they return a real-time quote. For the quote to update, you have to refresh the page again.

    Other sites provide streaming data - An application sends the list of symbols that you are watching to the server, then the server sends quotes and updates as they occur, without any need to refresh anything.

    Both types of sites provide real-time data. However, the streaming will be MUCH better.

    In QuoteTracker, all streaming sources have the word "STREAMING" in the name. For others, QT automatically refreshes the quotes for you.

    Another note: even if a site is streaming, does not mean it shows every tick (tick-by-tick quotes). Scottrade for example is an aggregated datafeed. There may be more than one trade between updates sent from the server.

    In general, Scottrade is good to demo the system, but their free data source is not the most reliable (particularly the free one). Who do you sue for your broker? In many cases, the broker will provide better data for you.

    Jerry Medved
  5. gordo



    Thank you for your response, that makes more sense. So it sounds like that even though the data that I am demoing on is real time, it may only be a few ticks every so many moments as opposed to everything that is taking place on the trading floor - as would often be reflected with a premium data source.


  6. If you are using Scottrade, then yes, the data is aggregated, though not nearly as much as it would be with an auto-refresh quote source. Scottrade's data should be more than enough for charting, but not enough for T&S.

    What broker do you use?