> -----Original Message----- > From: Alex Peshkoff via Firebird-devel [mailto:firebird- > de...@lists.sourceforge.net] > Sent: Tuesday, September 19, 2017 10:19 AM > > > I'm curious about why there is no index on SEC$USERS.SEC$USER_NAME (*) > > You are right - because it's virtual table.
Thanks for confirming, as expected although not what I had hoped for. Having database with a couple of thousand users it doesn't feels optimized doing a natural scan every time I want to look up a user. > > and about the reason as to why there is a difference between the usage of > VARCHAR and CHAR on tables that seems related. > > Use of CHAR for system tables is typical solution. What about related fields > in > tables used by plugins - they are logically related, but separated by plugin > code > and plugin is free to choose any format to store that data. One can write > plugin > that stores user's list in non-firebird database or even in text file. Understood and makes sense in that perspective. > > And if there would have been an index, would a UNIQUE INDEX on SEC$USERS > (SEC$USER_NAME, SEC$PLUGIN) been correct? > > If virtual table _could_ have indices - yes, that pair is unique. I see that I didn't express myself clearly, what I meant was that SEC$USER_NAME alone cannot be guaranteed unique if mixing different plugins, but I take it that's how you read it and answered accordingly. :-) Thanks for your time Alex. Regards, Magnus Johansson ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
