A Boolean parameter may be used to determine what task to fulfill. In this case the routine has multiple tasks and does not satisfy the separation of concerns principle.
Notes
Refers to the column pg_proc.prokind and thus works starting from PostgreSQL 11. There could be Boolean parameters for other reasons than being flag parameters. There could be multiple routines with the same name but with different parameters in the same schema (overloading). Thus, for the unique identification of the routine it is necessary to present also its parameters in addition to the schema name and routine name. The query does not consider the routines that are a part of an extension. In the returned body of routine the query replaces each newline character with the line break (br) tag for the better readability in case the query result is displayed in a web browser.
Type
Problem detection (Each row in the result could represent a flaw in the design)
Get rid of the flag parameters by dropping the original routine and creating multiple routines, each of which has a more specific task.
Data Source
INFORMATION_SCHEMA+system catalog
SQL Query
SELECT
pg_namespace.nspname AS routine_schema,
pg_proc.proname AS routine_name,
pg_get_function_identity_arguments(pg_proc.oid) AS parameters,
CASE WHEN pg_proc.prokind='f' THEN 'FUNCTION'
WHEN pg_proc.prokind='p' THEN 'PROCEDURE'
WHEN pg_proc.prokind='w' THEN 'WINDOW FUNCTION' END AS routine_type,
regexp_replace(regexp_replace(pg_get_functiondef(pg_proc.oid),'<','<','g'),'[\r\n]',' ','g') AS routine_src
FROM
pg_catalog.pg_proc,
pg_catalog.pg_namespace
WHERE
pg_proc.pronamespace = pg_namespace.oid
AND pg_proc.prokind<>'a'
AND pg_proc.proname NOT IN ('f_assume_you_must_use_files', 'f_check_format_comma_separated_list', 'f_check_password', 'f_default_value_with_no_match')
AND EXISTS (SELECT 1 FROM
information_schema.parameters AS p
WHERE p.specific_schema=pg_namespace.nspname AND
regexp_replace(specific_name,'_[0-9]*$','')=pg_proc.proname AND p.data_type='boolean')
AND pg_get_functiondef(pg_proc.oid)~*'([[:space:]]IF[[:space:]]|[[:space:]]CASE.*[[:space:]]WHEN.*[[:space:]]THEN.*[[:space:]]ELSE.*[[:space:]]END)'
AND pg_namespace.nspname NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
AND NOT EXISTS (SELECT 1
FROM pg_catalog.pg_depend d
WHERE EXISTS (SELECT 1 FROM pg_catalog.pg_extension e WHERE d.refobjid=e.oid) AND
d.objid=pg_proc.oid)
ORDER BY routine_schema, routine_name, parameters;
Categories
This query is classified under the following categories:
Name
Description
Comfortability of database evolution
Queries of this category provide information about the means that influence database evolution.
Does not work in some earlier PostgreSQL version
Queries of this category provide information that was not available in some earlier PostgreSQL version
User-defined routines
Queries of this category provide information about the user-defined routines