Hi Prashanth,
Thanks for your help.
Which value did you set in the Number of Bars (Database
Settings) ?
Something goes wrong on my end. If I keep 100 000, in few months my
index won't cumulate quotations.
Best regards
Le 05/09/2010 13:14, Prashanth a écrit :
I think the 500000 limit is with regard to Number of Bars (Database
Settings) and not with regard to total size of each ticker. For
example with
no major issue my Index data currently has 3573277 quotes. Backtesting
may
be bit sluggish, but I accept it since it gives me a very large time
frame
to test with.
Cheers
Orashanth
----- Original Message -----
From: "Reinsley" <[email protected] <mailto:reinsley%40yahoo.fr>>
To: <[email protected] <mailto:amibroker%40yahoogroups.com>>
Sent: Sunday, September 05, 2010 16:08 PM
Subject: [amibroker] max bars database settings understanding
>
> Hi,
>
> I grab the quotations from IB.
>
> Regularly datas disappear from my Index symbol.
>
> I made mistakes before to understand how database settings are
important.
> My setting was 100000 and every year I have lost datas when the
database
> has reached the maximum .
>
> My index receives a quotation every 30 seconds. My minimum time unit
is 1
> minute. I get about 510 " 1' bar " per day,
> per month : 510 x 20 = 10200
> per year : 10200 x 12 = 122400
>
> I want to keep my Index's whole history. I read that the default max is
> 500 000.
>
> Does it mean that my index can't be more than 4 years ?
>
> This point is confirmed by TJ's post specifiing the following... ( An
> answer to Joseph Biran, Sidartha, about database size ).
>
>>> This key is a "hidden extra feature" for advanced users having
>>>computers powerful enough to handle extra load.
>>>By default the key does not exist and then the default max is
>>>500000.
>
>>>Tomasz Janeczko
>
> My Pentium IV is not powerful. I'd like to fully understand the
> involvements before to shift to i7 family and S7.
>
> TJ's comment is in tune with AB warning "increasing this value can
degrade
> the performance".
>
> The load factor is higher.
> I set 200000 an the load factor is 97%.
> I set 100000 an the load factor is 57%.
>
> The load factor is higher with the same number of bars, I supposed that
> more RAM is reserved. So the ratio is worst.
>
> The point that drives me crazy, I use mainly the Index in daily or
weekly,
> sometimes in hourly, so I do not need to keep it in 1'. EOD is not
enough,
> hourly at least.
>
> I don't understand the best way to keep the datas concerning the Index.
> Should I build, at the end of every day, an hourly and daily and weekly
> handmade symbol into four separated time unit ? It'a a bit heavy to
> manipulate.
>
> Actually I kept backups but the AB format changing with EUR at the end
> after v:5.27 does not allow to merge and recover my backups. No way to
> open them into Excel and to re-inject into AB.
>
>
> The second major point is that this general max bars database
setting is
> common to future contracts and Index (and stocks, I don't use).
> Future needs about 50000 for a quarterly contract. My future
contracts are
> montly, it's roughly 35000 bars in 1' for two months of quotations.
> I can't imagine the constraints for people that store a thousand of
stocks
> datas and Indexes, grabbed in 1' and used in hourly and daily for
analyse.
>
> Any help appreciated to keep Index history as long as possible without
> destroying the load factor, and if somebody knows how to extract backup
> datas and recover them from old version ?
>
> Best regards
>
>
>
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