Why sometimes AB doesnt wait for backfill even if set up?

Some scans do no wait. I see the plugin backfilling lots of symbols but the scan ends much before.

The scan ended, but the backfill is still running.

It is intelligent. It waits only if symbol was not backfilled already and streaming. Symbols that are currently streaming don’t need backfill because they are up to date.

What you might see are backfill requests from other activities because there are many backfills done in parallel asynchronously, not only from Analysis but also from charts. There is also a wait queue that you don’t see. The whole thing is more complex that average user can dream of.

Thanks Tomasz. I see, but I was scanning about 2000 symbols. It looked like the scan ended too soon. I just have one chart open. Some scan result dates where not current, when to that symbol on the chart, the chart updated scanned again, and the result time was current. Giving the impression AB was not really waiting to have all the data updated.

Please be aware that you are doing something that is prohibited by IQFeed and not supported by us.

Theoretically – that should work after session hours, but please bear in mind what Jay from IQFeed wrote on the in this thread:
http://finance.groups.yahoo.com/group/amibroker/message/149624

Quote from IQFeed representative:

"With IQFeed, we don't limit through our API the number of symbols you receive backfill data on. We also don't have a technical limit to how often you can watch/unwatch symbols. This
being said, we do have policies which don't allow API developers to
programatically circumvent
the symbol limit in which a customer subscribes to.
Switching between portfolio's within the course of a trading day is perfectly
acceptible. Contantly watching and unwatching symbols in order to get around the
symbol limit is not. We have subscription options that go as high as 1800
symbols with DTN.IQ. "

Running scan/exploration/backtest that exceeds subscription limit would qualify for the practices prohibited by IQFeed service mentioned above. If you want to ensure data-quality and no surprises, you need to stay within the subscription limits. Exceeding it is definitely going to cause problems.

Ok I see. But this would be constant backfilling. lets say every 5 minutes or 10, or 15. Not watching / unwatching. In fact I dont care about their realtime service. Do you think this also violates their TOS?

Is it possible to disable real time accesses to IQFeed, and just use backfills from AB??

To be honest, at the end there lots of obstacles to make things useful.

AB can do scans is really fast but then the data provider doesn't want you to scan the whole market...

You don't understand how IQFeed API works.

You are NOT allowed to do "just backfills" over and over again. You are expected to choose upto 500 symbols, backfill them and start streaming (i.e. "subscribe to symbol") to AVOID subsequent backfills. Backfills are costly. You are not supposed to abuse their servers the way you ask. You are not supposed to backfill over and over 2000 symbols every few minutes with 500 symbol subscription. This is abuse of service. Plain and clear.

They want you to purchase their higher end subscription if you want more symbols.

As a 3rd party developer I am not allowed to build the software against their guidelines and certainly won't help you with abusing their service.

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