Hi, depending on what you want to do... You can use SQL but you must have in-depth knowlegde of the specific database sw. Logical and mostly physical database design is crutial to success. Both designs must be very efficent. Generally SQL database engine is used as a storage system. So it is bit overkill.
Using SQL is handy if you want to store data and from this store you want to prepare/transform/export data to other processes. In such case it is very flexible. You CAN play back IB tick data at real time speed (~300ms snap shots) for a few tickers directly from SQL db. That should not be a problem with a good db design and on a good hw. Going beyond this limit is not for SQL! You must also consider SQL database resource needs. Disk and memory are needed to achive good performance. A binary file based storage system is very efficent but no really flexible. SQL is flexible but not efficient... You have to choose what you need.. Regards, Y -------------------------------------------------- From: "Tomasz Janeczko" <[email protected]> Sent: Monday, May 18, 2009 9:37 PM To: <[email protected]> Subject: Re: [amibroker] ODBC + DDE > SQL database & ODBC is wrong path for high-perf RT. > > ODBC is rather slow as it was never designed by Microsoft to be used as a > real-time streaming tool. > Also all standard SQL databases are way too slow for real time > applications. > > Only proprietary binary low-level dbs like AmiBroker own, that are very > low level and not SQL based > are able to offer right speed. > > As for interfaces - only direct APIs (like AmiBroker Dev Kit) that operate > directly > on binary data via direct pointers and no need for copying data and > without SQL overhead are fast enough. > > For commercial databases that offer better performance than SQL see > Berkeley DB > http://www.oracle.com/database/berkeley-db/db/index.html > > (Read their white papers that explain why all relational, sql-based > databases are simply too slow) > > Best regards, > Tomasz Janeczko > amibroker.com > ----- Original Message ----- > From: "lucianomt" <[email protected]> > To: <[email protected]> > Sent: Monday, May 18, 2009 6:30 PM > Subject: [amibroker] ODBC + DDE > > >>I am trying to set up real-time feeds on AB. I have a SQL database that >>contains all the necessary data. The only problem is the >>very high delay I get using the ODBC plug-in. To pull up about 1000 bars >>for 150 tickers takes approx. 10 minutes, which makes it >>impractical for real-time. (The same process using local database takes 1 >>second.) >> >> So my first question is: am I doing something wrong? Is there any way to >> improve this performance significantly or is the ODBC >> solution inherently slow? >> >> If nothing can be done to improve ODBC, I thought I could upload the >> historical data into the local database and them use a >> different source, say DDE, to update the real-time quotes for the current >> day. Would that solution work? >> >> Please note that the historical data needs to be updated daily since it >> is a total-return series. >> >> >> >> ------------------------------------ >> >> **** IMPORTANT PLEASE READ **** >> This group is for the discussion between users only. >> This is *NOT* technical support channel. >> >> TO GET TECHNICAL SUPPORT send an e-mail directly to >> SUPPORT {at} amibroker.com >> >> TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at >> http://www.amibroker.com/feedback/ >> (submissions sent via other channels won't be considered) >> >> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: >> http://www.amibroker.com/devlog/ >> >> Yahoo! Groups Links >> >> >> > > > > ------------------------------------ > > **** IMPORTANT PLEASE READ **** > This group is for the discussion between users only. > This is *NOT* technical support channel. > > TO GET TECHNICAL SUPPORT send an e-mail directly to > SUPPORT {at} amibroker.com > > TO SUBMIT SUGGESTIONS please use FEEDBACK CENTER at > http://www.amibroker.com/feedback/ > (submissions sent via other channels won't be considered) > > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG: > http://www.amibroker.com/devlog/ > > Yahoo! Groups Links > > > >
