Hello
2014-03-07 16:42 GMT+01:00 Catherine Devlin <catherine.dev...@gmail.com>: > On Thu, Mar 6, 2014 at 12:09 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > Hm ... the code in psql's describe.c is not terribly conducive to that. > > Parsing of the backslash command, execution of the query/queries, and > > presentation of the results is all rather tightly bound up; you'd have > > to think about how to decouple those. > > I just looked into describe.c, but it was virtually my first look at C > in 15 years and I'm pretty intimidated. > > Come to think of it, I really like the idea of moving the query > execution and presentation of results out into plpgsql functions in > template0; then it would be super-easy for applications to utilize > them. Parsing the command could stay with psql, because the > applications would probably want to do that parsing themselves, > anyway. > I don't think so using plpgsql can be good idea: a) client side is better for implementation version independent code b) possible bugs in plpgsql code should not be fixed without living database - so any bug release can be significantly more dangerous than now. Regards Pavel > > The trouble is that psql is written to work against older databases, > so if the code were stripped from describe.c in favor of calling > stored functions, those commands would stop working against older > PostgreSQL installations; and if the code were left in describe.c, > then the same function would exist in two different forms in two > different places, with all the maintanability problems that implies. > > Is there a way around this I'm not thinking of? > > Alternately, I may just give up and write my own, freestanding, > approximate implementation of the meta-commands with no effort to > actually replace the native one. It could still be useful to > application developers if they find out about it. > > -- > - Catherine > http://catherinedevlin.blogspot.com > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general >
