Hello Thor, El dc 15 de 03 del 2006 a les 09:24 +0100, en/na [EMAIL PROTECTED] va escriure: > We are very interested in the possible performance improvements in the new > Pro version. The ability to have complex indices and queries will be > helpful. > However, in our application a response time in the order of milliseconds is > unacceptable. We were hoping that the built in caching would come to our > rescue, but we have not been able to get the performance we need. Instead > we have implemented our own (very ad-hoc) caching. So a couple of > questions: > > Anyone know of a more standard way to have faster queries (in the sub > millisecond range). Shouldn't this be possible if the result of a query is > cached and sits in RAM?
Well, generally speaking, keeping the result of a query in RAM will always speed-up a query. Even if this is not implemented specifically, re-doing the same (or similar) query several times, will also improve the time because the index is probably in the filesystem cache (this depends on how large the index is and how much memory do you have). Regarding PyTables Pro, our (preliminary) timings shows that, for simple queries involving one single index (remeber, you can always create a complex index to speed-up a complex query) we can be in the sub-millisecond range whenever the index is already in cache, that is, if you have already run the query (or other similar) before, and for tables up to 50 millions of rows. When the query is not in cache, and for tables up to 1 million of rows, we expect sub-hundreth of second times, while for tables with more than 1 billion of rows, our goal is sub-second (modern relational engines usage is prohibitive in such extremely large tables scenarios). See [1] for some slides about PyTables Pro measured performance and our goals (only for non-cached queries). [1] http://www.carabos.com/downloads/resources/pytables-cstables% 40hdf__20051201.pdf > > Are there any pricing information for PyTables Pro. What are the licensing > options? I'm sorry, but we don't have a definitive pricing/licensing schema yet. But, just for your information, the prices will be around one thousand euros (maybe a little more or a little less, but in that order of magnitude) for one license. Regards, -- >0,0< Francesc Altet http://www.carabos.com/ V V Cárabos Coop. V. Enjoy Data "-" ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid0944&bid$1720&dat1642 _______________________________________________ Pytables-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/pytables-users
