On Mon, May 09, 2011 at 02:15:04PM +0300, Pandelis Theodosiou wrote: > a) keep the last (longitude, latitude) pair for every receiver stored > in your script, too, besides the db. When a new pair of values > arrives, compare it with the current and only if it is different, send > the "INSERT" query to the database.
This will only work if I can guarantee that the database query is finished before the next (longitude, latitude) pair arrives. Otherwise, I'll lose the previous pair. Storing a list of (longitude, latitude) pairs won't work either: the database queries are executed in separate threads, and I can't control the order in which they will finish. So I have no correspondence between the query result and a (longitude, latitude) pair. For GPS data, this might not be an issue, since a new position arrives only about once a second. But other data (e.g. the current speed) are sent every ten ms or so. For these, I have to make sure that the current data corresponds to the query result. > b) When a new pair of values arrives, send a query (or stored > procedure) that tells the database to check and "INSERT" only if the > pair is different that the latest. That is an interesting option, since it moves the responsibility from the Twisted server to the database. Thanks & best regards, Albert -- Albert Brandl Weiermayer Solutions GmbH | Abteistraße 12, A-4813 Altmünster phone: +43 (0) 720 70 30 14 | fax: +43 (0) 7612 20 3 56 web: http://www.weiermayer.com _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
