Well, I think I just solved that problem. I had turned on the
"enable" radio button on the local data storage, but I had not selected "local
database" in the drop down menu for data source. I thought I was supposed to
leave it as "Metastock Data" This isn't necessary with the QP database.
But it is with PremiumData. Now the constant disk access is gone and AB
goes through all 18k delisted symbols on a moderately complex backtest in a
fraction of the time. And I never saw the broker.exe memory usage go
over 250m.
Not sure if there is a downside to making this a local
database, but, wow, is it much faster. Instead of taking over 10
minutes, it took 2 minutes.
Thanks for all the help. Sorry I was
so slow on figuring it out.
On Fri, Apr 11, 2008 at 9:09 PM, ges x <
ges8ges@xxxxxxcom> wrote:
Graham,
I checked the
local storage check box, but it did not seem to increase the speed or
diminish the disk accessing. Is this because Premium Data is in Metastock
format? Do I need to select "local database" as the data source in the
drop down menu? Or is it just that the database is too large for my
memory and data settings? I have allocated 1GB to AB for data (max
megabytes), although when I check in Task Manager I can't ever see that it
is using nearly that much and yet the data is not in memory.
OK, I
just now monitored Broker.exe's mem use in Task Manager. When I tested
on the QP database (which all goes in memory after the first run through and
is extremely fast), Task Manager showed that broker.exe was using about 542k
memory. When I switched over to Premium Data database and ran an
exploration the mem usage never got much over 300k even though the database
settings are the same, and when run a second time, the data is still
accessed from disk and not from memory.
It is the nature of the
systems I have developed that the explorations and tests must be run over
most of the database so anything I can do to speed it up is a huge
help.
I appreciate that AB is very fast, but if I can speed up the
data access for these large Premium Data files I'll be more
productive. Maybe increasing my RAM from 2G to 4G would help, although
that doesn't appear to be the issue from what I've seen in Task
Manager.
On Fri, Apr 11, 2008 at 4:35 PM, Graham <
kavemanperth@gmail.com> wrote:
Enable local data storage in database settings window
--
Cheers
Graham Kav
AFL Writing Service
http://www.aflwriting.com
On 12/04/2008, ges
x <ges8ges@xxxxxxcom> wrote:
I think Paul's suggestion not to run so many symbols is a good one
and I can pare down the list for many tests, but there are some for
which I need to run over 20,000.
How do I go about putting the
Premium data into native AB format? This database will be used for
historical backtesting and does not need to be updated, or not often, so
it would make sense to move this over to native AB format. Is this
a simple process?
Thanks.
