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Re: [amibroker] Re: Size of Database...



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sidhartha70>>>So as a DB management strategy, it's best to perhaps have a 
large DB
for backtesting purposes only... and a much smaller DB for live
trading, charting, symbol swithcing etc..etc...??
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I think I remember that SET BARS REQUIRED will "NOT" stop Amibroker from 
looking back through the last 30 years even though I am looking at only the 
last day.

I would sure like a feature in Amibroker that would make SET BARS REQUIRED 
lookback only 101 days when the indicator looks back only 100 days.

My backtesting days officially ended a few days ago.

My backtesting consisted of viewing my indicator buy signals against 30 
years of historical data.

Even though I no longer backtest, I would still like to have a 30 year 
database, and here is why.

Those symbols that are less volatile tend to have a decent amount of pattern 
similarity in my indicators  as they enter into a NEW uptrend, after having 
been on a long term DOWNTREND.

If I keep my 30 year database, then when I get a BUY signal, I can look back 
at the beginning of the previous new uptrends that occurred over the last 30 
years. This lookback helps me decide how good the signal is. Ron D



















----- Original Message ----- 
From: "sidhartha70" <sidhartha70@xxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Thursday, August 21, 2008 8:59 AM
Subject: [amibroker] Re: Size of Database...


> Thanks TJ.
>
> So as a DB management strategy, it's best to perhaps have a large DB
> for backtesting purposes only... and a much smaller DB for live
> trading, charting, symbol swithcing etc..etc...??
>
> Thanks
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>>
>> Using 10x more data per symbol will give you slow down in all areas.
>> 2 million bars is 64 MB per symbol of quote data and 8 MB per single
> AFL array
>> (if quickafl is not used). As formulas depending on complexity can
> use hundreds of arrays
>> this means approaching gigabytes of RAM.
>> Handling that much of data is not "easy". Remember than RAM bandwidth
>> is limited to few GB per second. Therefore just accessing that amount
>> of data is question of seconds, not counting the calculations.
>>
>> Best regards,
>> Tomasz Janeczko
>> amibroker.com
>> ----- Original Message ----- 
>> From: "sidhartha70" <sidhartha70@xxx>
>> To: <amibroker@xxxxxxxxxxxxxxx>
>> Sent: Thursday, August 21, 2008 2:48 PM
>> Subject: [amibroker] Re: Size of Database...
>>
>>
>> > Anyone...?
>> >
>> > Many Thanks
>> >
>> > --- In amibroker@xxxxxxxxxxxxxxx, "sidhartha70" <sidhartha70@> wrote:
>> >>
>> >> This may have been answered before, but...
>> >>
>> >> I set up two DB's in AB... both IQ Feed tick DB's.
>> >>
>> >> 1. Is 200,000 bars per symbol.
>> >> 2. The second is 2,000,000 per symbol.
>> >>
>> >> Practially, operationally, where will AB be slower in the use of the
>> >> second DB...?? In charting? Backtesting (obviosuly)? In symbol
>> >> switching etc...?
>> >>
>> >> I'm just trying to work out how motivated I should be to have small
>> >> DB's...
>> >>
>> >> Thanks
>> >>
>> >
>> >
>> >
>> > ------------------------------------
>> >
>> > Please note that this group is for discussion between users only.
>> >
>> > To get support from AmiBroker please send an e-mail directly to
>> > SUPPORT {at} amibroker.com
>> >
>> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> > http://www.amibroker.com/devlog/
>> >
>> > For other support material please check also:
>> > http://www.amibroker.com/support.html
>> > Yahoo! Groups Links
>> >
>> >
>> >
>>
>
>
>
> ------------------------------------
>
> Please note that this group is for discussion between users only.
>
> To get support from AmiBroker please send an e-mail directly to
> SUPPORT {at} amibroker.com
>
> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> http://www.amibroker.com/devlog/
>
> For other support material please check also:
> http://www.amibroker.com/support.html
> Yahoo! Groups Links
>
>
>



------------------------------------

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