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Tomasz,
Thank for the quick reply. I now understand that there is a speed
reduction if there are more than 1,000 tickers in a folder.
One more question: is this always the case? Or, is the speed
reduction no longer a problem once AB lists the tickers in the
broker.master file?
My situation is this: I want to have about 5,000 inactive stocks in
the same database as active stocks, but may will have the same
ticker sysbol as these get reused. One way to handle this is to give
each inactive ticker a prefix (like, _IBM). This has the advantage
that a simple sort will put all the inactives together for each of
watchlist management. The byproduct is that all the 5,000 inactives
will end up in the same AB data folder (eg, "_").
The alternative is to use a suffix for inactives (eg, IBM_x).
Sorting is not quite so easy with a suffix, but it is still possible
to select out the inactives using AB's strright call in a scan. Of
course, this approach will distribute the inactives among AB's 26
regular data folders (A, B, C, etc).
I am open to any advise you or others may have for managing
inactives and actives in the same database.
b
--- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <amibroker@xxxx>
wrote:
> b,
>
> Generally speaking all Microsoft file systems (FAT, FAT32, NTFS)
slow down
> when there is more than 1000 files in single folder. Exact results
depend
> on hard disk, disk cache, RAM size, disk fragmentation, etc.
> Loading database however does not require reading all files as
AmiBroker
> maintains broker.master file that contains all info that need to
be loaded
> at startup. Individual files are accessed only when needed (when
quotes
> must be read, for example during scan).
>
>
> Best regards,
> Tomasz Janeczko
> amibroker.com
> ----- Original Message -----
> From: "b519b" <b519b@xxxx>
> To: <amibroker@xxxxxxxxxxxxxxx>
> Sent: Sunday, June 08, 2003 3:37 PM
> Subject: [amibroker] AB data base structure and speed (perhaps
only Thomasz can answer)
>
>
> > Does it matter if one puts several thousand tickers into a
single AB
> > data folder. For example, if one makes all inactive stocks with
a
> > prefix like _IBM? That will put about 5,000 stocks into the "_"
> > folder in the AB database.
> >
> > Does having 5,000 or more tickers in the same folder slow AB
down
> > when retriving data?
> >
> > b
> >
> >
> >
> >
> > Send BUG REPORTS to bugs@xxxx
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