Re: Instead of DROP function use UPDATE pg_proc in anupgrade extension script - Mailing list pgsql-hackers

Hello,

When creating an extension upgrade sql script, because the function does not have the same parameter names and/or parameters type and/or the result types changes, there is the need to drop the function because otherwise the CREATE OR REPLACE of the new signature will fail.

So for example:

having the following function:

SELECT proallargtypes, proargmodes, proargnames FROM pg_proc WHERE
proallargtypes = '{25,20,20,16,23,23,20,20}'   AND proname = 'pgr_edgedisjointpaths';
-[ RECORD 1 ]--+-----------------------------------------------------------------------------
proallargtypes | {25,20,20,16,23,23,20,20}
proargmodes    | {i,i,i,i,o,o,o,o}
proargnames    | {"","","",directed,seq,path_seq,node,edge}

When adding extra OUT parameters, because the result types (&names) change, the function needs a DROP:

-- Row type defined by OUT parameters is different

 ALTER EXTENSION pgrouting DROP FUNCTION pgr_edgedisjointpaths(text,bigint,bigint,boolean);

 DROP FUNCTION IF EXISTS pgr_edgedisjointpaths(text,bigint,bigint,boolean);

but doing that, objects that depend on the function. like a view, get dropped when using CASCADE in the ALTER extension, and functions that use the pgr_edgedisjointpaths internally don't get dropped.

So, I must say that I experimented: instead of doing the drop, I made:

UPDATE pg_proc SET

                          proallargtypes = '{25,20,20,16,23,23,23,20,20,701,701}',

                          proargmodes = '{i,i,i,i,o,o,o,o,o,o,o}',

                           proargnames = '{"","","","directed","seq","path_id","path_seq","node","edge","cost","agg_cost"}'

 WHERE proallargtypes = '{25,20,20,16,23,23,20,20}'   AND proname = 'pgr_edgedisjointpaths';

And CASCADE was not needed, and the view remained intact.

So, I want to know how "safe" can you consider the second method, and what kind of other objects do I need to test besides views.

My plan, is to use the second method:

- when the current names of the OUT parameters don't change, and there is an additional OUT parameter

- when the current names of the IN parameters don't change, and there is an additional IN parameter with a default value

Thanks

Vicky Vergara