Best way to refresh chart data if internet drops?

[NinjaTrader_PatrickG]

Ah, thanks. Then my original idea is still valid:

If he's viewing his 10 years of Minute based data in a chart window (even if that workspace is open but not active, even if that 10yr chart window is minimized), he should never reload from any other chart window with minute data for that same instrument. Well, "never" is a strong word there, let's just say "refrain" ...

Because, if he does, the max minute data will be downloaded (downloaded, not just re-read from disk), because that 10 year chart overrides all the others.

But, to be clear, there is no real penalty when he does this. No loss of any of his 10 years of prior minute data, the only "penalty" is time spent downloading and replacing (eg, refreshing) minute data he already has.

And, just to confirm, the minute data will be downloaded even if it already exists on disk -- such that newly downloaded minute data will replace the same minute data (if already present) on disk.

And finally, NT historical servers do not have 10 years of minute data for any instrument, so downloading max minute data is really only about 1 years worth, is that right?

Are all these statements correct?

This is correct except for the amount of available data from NinjaTrader historical data servers. Keep in mind also that some providers supply their own historical data. Here are the values for NinjaTrader's historical data servers:

• Tick data: deleted after 366 days
• Minute data: virtually never deleted, goes back to 2006
• Daily data: virtually never deleted, goes back to 2009

[bltdavid]

This is correct except for the amount of available data from NinjaTrader historical data servers. Keep in mind also that some providers supply their own historical data. Here are the values for NinjaTrader's historical data servers:

• Tick data: deleted after 366 days
• Minute data: virtually never deleted, goes back to 2006
• Daily data: virtually never deleted, goes back to 2009

Wow, thanks. Ok, then yeah, that "penalty" of downloading max minute data if his 10yr minute chart is up can be pretty severe amount of time spent waiting -- looks like all 10 years would be downloaded!

[bltdavid]

I'm not sure about that? I think "Reload all historical data", (Cntrl+Shift+R), or the option available from the contextual right-click on chart will actually erase and downlaod from your provider for the # of max days, of that interval on the chart.

Yep, I was wrong.

Thanks forrestang, this post was actually a very good question.

I learned a couple of things, of which I am thankful.

IMHO, the things we learned today should have been documented.

For example, this page,
http://ninjatrader.com/support/helpG...rical_data.htm

does not mention these facts:

1. "reload == download".
In fact, the above page seems to allow the reader to surmise that "Reload All Historical Data" reads from disk first and only downloads missing data -- in fact, it implies to really force the download of data you would use the Historical Data Manager instead.

2. "days to download is highest 'Days to load' of all charts"
This little factoid is missing, but can have a big impact on your workflow. I mean, this massive downloading can cause considerable grief as you wait for NT to silently reload enough data to satisfy all affected charts. It can be hard for the uneducated to know why this "simple reload of a 10 day chart" takes so long.

What's worse is that, in your case, for example, if you're looking at a simple 10 days of a 5-minute chart, and reload data inside this chart only -- it is that damned other 10yr minute minimized chart which will make this seemingly simple operation take forever -- and you won't really know why.

Edit:
I reported this as an issue to the NT8 Beta forum:

http://ninjatrader.com/support/forum/showthread.php?t=88470

[koganam]

Yes, this is correct. NinjaTrader reloads all charts of the same instrument and interval type when you choose to reload on one of those charts.

There are three fundamental data types to consider: Tick, Minute, and Daily. Reloading historical data in one chart of an instrument and data type will reload all charts of that instrument and data type. Another example other than my previous minute-based charts would be tick-based: A 4 Range CL chart and a 255 Tick CL chart. These are both tick-based and historical data will reload for both when one is reloaded.

As I recommended, if you are not wanting to overwrite your locally stored historical data, the best route would be to manually download using the Historical Data Manager.



All windows, even if minimized (or in a different open workspace which is not the current active workspace) are actively loading and take up PC resources.Reloading will affect these charts as well.

In which case, bltdavid's concerns about the documentation, or rather the lack of clarity thereof, are very important. Anything that nukes data must carry a warning, even if said data will be replaced, and especially so as the historical server may not replace all the data, simply because it does not have it. e.g., the 10-year case here. I would be really annoyed, even if I can get no restitution, if 9 years of my stored data are wiped out because I have a 10 year chart in the background, reload all data, and the historical data server will only replace 1 year of data (or whatever length of data it does have) after nuking 10 years of data.

Of course, if the historical data server will only delete and replace the exact length of data that it actually has, that makes the issue moot.

[bltdavid]

In which case, bltdavid's concerns about the documentation, or rather the lack of clarity thereof, are very important. Anything that nukes data must carry a warning, even if said data will be replaced, and especially so as the historical server may not replace all the data, simply because it does not have it. e.g., the 10-year case here. I would be rally annoyed, even if I can get no restitution, if 9 years of my stored data are wiped out because I have a 10 year chart in the background, reload all data, and the historical data server will only replace 1 year of data (or whatever length of data it does have) after nuking 10 years of data.

You're kinda making my point about the insufficient nature of the documentation on this feature. I mean, a couple of extra paragraphs explaining what NT does, like I said in the NT8 issue thread, can go a long way in answering the 'Holy-Crap-What-is-NT-doing' type of question you posed here.

So, I'll expand on your point: and that is: damn right, data is important! So a few extra sentences/paragraphs to expand on an important feature that affects data should have allayed your concerns. But, alas, you were alarmed, because you didn't know, because the docs don't say -- and you have to ask the question (perhaps asked dozens of times before you) to find out.

Extra informative documentation should be viewed as a positive for the user, and not as usurping of NT support's role to the user.

This idea of 'documentation terseness is on purpose' pervades too much of the NT support attitude. I think well written documentation is not, by definition, terse -- it should be informative and helpful in answering both basic and advanced questions.

Good documentation has a writing style that flows naturally from the basic to the advanced -- as the reader progresses into the content, newbies stop early because what they probably seek is basic, and so the easy stuff is always answered early in the first one or two sentences/paragraphs/sections.

The experienced & advanced crowd will (naturally) read the whole thing and get some detailed additional knowledge about that feature.

As a newbie gains more experienced, he can choose to revisit the doco for that feature and read the additional sentences/paragraphs/sections he may have glossed over on his first reading.

Unfortunately, Patrick seems to disagree with this 'purpose of documentation' idea.

Of course, if the historical data server will only delete and replace the exact length of data that it actually has, that makes the issue moot.

This.

I'd bet dollars to donuts: no prior historical data is nuked unless NT knows beforehand it has replacement data available to download.

[NinjaTrader_Brett]

Feedback received on our documentation. Its been an item we wanted to address for a while but given that we haven't changed much from NT7 and we have a level of documentation which mirrors NT7 we have it on our backlog so we can focus on getting NinjaTrader 8 launched.

-Brett