29.11.2011 9:48, Dmitry Yemanov wrote: > 29.11.2011 12:35, Vlad Khorsun wrote: > >> > While i agree with you about SUBSTRING, i think the much better solution >> > will be to allow to index COMPUTED BY columns. It allows to not compare >> > potentially complex expressions at optimize time and to not write exactly >> > same expressions in every query where such index is required. > Perhaps. And we have such a request in the tracker, AFAIR. > > I'm just not really sure that adding a dummy column (that could never be > selected from explicitly) to improve the performance looks like a proper > approach.
Perhaps, better approach would be silently cut long index keys to implementation limit. This way we don't loose anything, just increase number of "real comparsions" with negative result during selects. -- SY, SD. ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-novd2d Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
