2015-06-28 14:26 GMT+02:00 Tomas Vondra <tomas.von...@2ndquadrant.com>:
> Hi, > > On 06/28/2015 08:01 AM, Pavel Stehule wrote: > >> >> you can use PL/pgSQL - but there are some limits >> >> * maintenance large plpgsql functions >> >> * the plpgsql functions or anonymous functions create a transaction >> borders - what should not be wanted >> > > But why is that a problem? Generally (sub)transactions are a good thing, > but if you want, you may create one huge function. If you want to > modularize this a bit, you may split that into multiple functions, but > that's an option, not a requirement. > > >> * I cannot to use psql variables simply in plpgsql code (plpgsql has >> not any macro language) - so some patterns are implemented in plpgsql >> less readable >> >> for example, if you can create a script that create some plpgsql >> function for specified PostgreSQL version, then using PLpgSQL for this >> purpose is suboptimal due less readability and maintainability >> > > I don't really see how a block of PL/pgSQL code is less maintainable than > a similar block of code written in a pseudo-scripting language specific to > psql. Actually I'd expect exactly the opposite, as PL/pgSQL has neat > features like exception handling and such, which is completely absent in > psql, or proper variables, which is somehow mimicked by session variables > in psql. > > If you really need to do the scripting outsite PL/pgSQL, there's plenty of > suitable tools for that purpose IMHO. Starting with bash, or languages like > Perl or Python. > <b>I don't propose psql scripting.</b> I propose simple statement for conditional statement execution. The core of my proposal are commands \if_ver_gt, \if_ver_lt Example: \if_ver_le 8.3.0 CREATE OR REPLACE FUNCTION unnest(anyarray) RETURNS SETOF anyelement AS $$ BEGIN ... END $$ LANGUAGE plpgsql; \endif instead DO $xx$ BEGIN IF version_le(version(), '8.3.0') THEN CREATE OR REPLACE FUNCTION unnest(anyarray) RETURNS SETOF anyelement AS $$ BEGIN ... END $$ LANGUAGE plpgsql; END IF; END; $xx$; > > And I think the same about readability ... > > > -- > Tomas Vondra http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services > > > -- > Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-hackers >
