How to display the function, procedure, triggers source code in postgresql?

Question

\df+ in psql gives you the sourcecode.

For function:

you can query the pg_proc view , just as the following

select proname,prosrc from pg_proc where proname= your_function_name; 

Another way is that just execute the commont \df and \ef which can list the functions.

skytf=> \df           
                                             List of functions
 Schema |         Name         | Result data type |              Argument data types               |  Type  
--------+----------------------+------------------+------------------------------------------------+--------
 public | pg_buffercache_pages | SETOF record     |                                                | normal


skytf=> \ef  pg_buffercache_pages

It will show the source code of the function.

For triggers:

I dont't know if there is a direct way to get the source code. Just know the following way, may be it will help you!

• step 1 : Get the table oid of the trigger:

    skytf=> select tgrelid from pg_trigger  where tgname='insert_tbl_tmp_trigger';
      tgrelid
    ---------
       26599
    (1 row)

• step 2: Get the table name of the above oid !

    skytf=> select oid,relname  from pg_class where oid=26599;
      oid  |           relname           
    -------+-----------------------------
     26599 | tbl_tmp
    (1 row)

• step 3: list the table information

    skytf=> \d tbl_tmp

It will show you the details of the trigger of the table . Usually a trigger uses a function. So you can get the source code of the trigger function just as the above that I pointed out !

Here are few examples from PostgreSQL-9.5

Display list:

1. Functions: \df+
2. Triggers : \dy+

Display Definition:

postgres=# \sf
function name is required

postgres=# \sf pg_reload_conf()
CREATE OR REPLACE FUNCTION pg_catalog.pg_reload_conf()
 RETURNS boolean
 LANGUAGE internal
 STRICT
AS $function$pg_reload_conf$function$

postgres=# \sf pg_encoding_to_char
CREATE OR REPLACE FUNCTION pg_catalog.pg_encoding_to_char(integer)
 RETURNS name
 LANGUAGE internal
 STABLE STRICT
AS $function$PG_encoding_to_char$function$

There are many possibilities. Simplest way is to just use pgAdmin and get this from SQL window. However if you want to get this programmatically then examinate pg_proc and pg_trigger system catalogs or routines and triggers views from information schema (that's SQL standard way, but it might not cover all features especially PostgreSQL-specific). For example:

SELECT
    routine_definition 
FROM
    information_schema.routines 
WHERE
    specific_schema LIKE 'public'
    AND routine_name LIKE 'functionName';

Slightly more than just displaying the function, how about getting the edit in-place facility as well.

\ef <function_name> is very handy. It will open the source code of the function in editable format. You will not only be able to view it, you can edit and execute it as well.

Just \ef without function_name will open editable CREATE FUNCTION template.

For further reference -> https://www.postgresql.org/docs/9.6/static/app-psql.html

\sf function_name in psql yields editable source code of a single function.

From https://www.postgresql.org/docs/9.6/static/app-psql.html:

\sf[+] function_description This command fetches and shows the definition of the named function, in the form of a CREATE OR REPLACE FUNCTION command.

If + is appended to the command name, then the output lines are numbered, with the first line of the function body being line 1.

additionally to @franc's answer you can use this from sql interface:

select 
    prosrc
from pg_trigger, pg_proc
where
 pg_proc.oid=pg_trigger.tgfoid
 and pg_trigger.tgname like '<name>'

(taken from here: http://www.postgresql.org/message-id/Pine.BSF.4.10.10009140858080.28013-100000@megazone23.bigpanda.com)