Oracle: Recompile Invalid Objects

Question: 

I  have packages and package bodies going invalid when I make schema changes.  How do I recompile invalid objects?

Answer: 

The Oracle database will invalidate objects if a dependent object is changed. If I rebuild a table, the indexes on that table will become invalid because they use the table's rowids and rebuilding the table changes a row's rowid. It is the same with objects like packages, procedures and functions.

In a development environment with lots of users working on the same objects this can become aggravating. Just remember that someone caused the database to invalidate the object. You can control this by controlling who changes objects in the database, or splitting the development into multiple schemas so that one section does not cause another's objects to become invalid.

You can run this query to find invalid objects, which may cause the ORA-06508 error:
select 
   comp_id, 
   comp_name, 
   version, 
   status, 
   namespace, 
   schema 
from 
   dba_registry;

You can invoke the utl_recomp package to recompile invalid objects:

EXEC UTL_RECOMP.recomp_serial('schema name');

Here is a script to recompile invalid PL/SQL packages, stored procedures, functions and package bodies.  You may need to this script more than once for dependencies, if you get errors from the script.

invalid.sql

Set heading off;
set feedback off;
set echo off;
Set lines 999;

Spool run_invalid.sql

select
   'ALTER ' || OBJECT_TYPE || ' ' ||
   OWNER || '.' || OBJECT_NAME || ' COMPILE;'
from
   dba_objects
where
   status = 'INVALID'
and
   object_type in ('PACKAGE','FUNCTION','PROCEDURE')
;

spool off;

set heading on;
set feedback on;
set echo on;

@run_invalid.sql