Early on in learning Stockalyze I thought running a trading system on a list of stock symbols would download the historical data.Your understanding is right. Just that the data for only those stocks get downloaded that you used in backtesting. It's not only backtesting, anything you do like creating chart, run stock screener, backtesting, or even if you had alert set and you started Stockalyze then the price history of required stocks are downloaded. So, Stockalyze fetches data always on on-demand basis.
For creating chart there is a small optimization. If data is already present then a chart is first created with existing data, so that you get to see the chart as soon as possible and also the download of price is started in the background and chart is updated if there is new data available. If there is no data existing then only you see "waiting for price history".
But now when I run a trading system, and then chart a symbol, I get the brief message "waiting for price history" then the chart is displayed.Are you getting this for same symbol you used in backtesting? Was backtesting done with Eod and you are creating intraday chart or vice versa? If not then it is a bug, but I doubt it. Please confirm. If it is bug it will be solved quickly.
So my question is:I suspect either the symbol or the periodicity of backtesting and chart don't match. Please confirm.
How did the system run a trading system and use historical data when, by displaying a chart for a symbol, Stockalye needs to retrieve historical data?
One more thing to note is that intraday data and EoD data are separate and so both require separate downloads.
Sorry for lengthy explanation but I am putting it here for everyone's help.