Hello,
Using external databases (no matter which one) is very slow compared to
AmiBroker native database (orders of magnitude for arrays)
and as such it does not make sense using it to speed up or get "more power"
because all theoretical benefits from using more than one core
would be wasted on slow external database.
External database lives in another process and any inter-process communication
layer is way more CPU intensive than just passing the pointer
inside one process (as AmiBroker works).
Best regards,
Tomasz Janeczko
amibroker.com
On 2010-07-03 00:49, Chris DePuy wrote:
I'll post a function shortly. Making sure you have the right format is tedious
and that is what the function deals with.
A tough part is following the instructions on /ODBC.html on how to make a so
called system DSN.
One reason to use a database is because it allow multiple writes and reads.
Sent to your iPad
----------------------------------------------------------------------------------------------------------------------------------------------------------------
*From: * Ted Byers <[email protected]>
*Sender: * [email protected]
*Date: *Fri, 2 Jul 2010 18:02:43 -0400
*To: *<[email protected]>
*ReplyTo: * [email protected]
*Subject: *Re: [amibroker] Re: Does running multiple instances of AB increase
processing power?
I don't know about the other issues discussed in this thread, except that for an application to truly get the maximum benefit from multiple cores or multiple
processors, it generally needs to be rewritten, not only to make extensive use of multithreading, but to manage precisely how to allocate computing tasks
among the available processors. In lieu of that, you're stuck with the same performance, but not adversely being affected by most of the other tasks the
system has to do, or running multiple instances of the program. These latter options do not scale well in terms of getting more work done faster.
Fortunately, for application programmers, there is Intel's threading building blocks library. Alas, for something like AmiBroker, which predates Intel's TBB,
using it well would require a major rewrite. That is something I'd recommend being done, but not something I'd expect any time soon.
What I do have extensive experience with is MySQL. It is open source, so it is free. You can implement what you need very quickly as long as you have a good
understanding of SQL. Installation is not for the faint of heart, but this is true of all the open source databases I have seen. It IS reliable, and is used
by a variety of businesses as a suitable, inexpensive alternative to MS SQL Server, Oracle, or IBM's DB/2. NB: I have not even looked at how to get AB to
talk to MySQL, but if you can get your data from AB in CSV files, getting it into MySQL is a trivially simple load SQL statement.
HTH
Ted
On Fri, Jul 2, 2010 at 5:47 PM, Rob <[email protected]
<mailto:[email protected]>> wrote:
Herman,
I don't know what sort of info you intend to pass between instances...
As for myself, I am sharing some .csv files... not arrays in and of
themselves...
I'd be interested in mysql as long as it was easy to implement, quick,
reliable and free (i.e. only some of my time required)...
