IS NOT DISTINCT FROM in routines

Query goal:

Avoid using IS NOT DISTINCT FROM because it makes the query planner to avoid using an index.

Query type:

Problem detection (Each row in the result could represent a flaw in the design)

Query reliability:

High (Few or no false-positive results)

Query license:

MIT License

Data source:

INFORMATION_SCHEMA+system catalog

SQL query:

Click on query to copy it

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(pg_get_functiondef(pg_proc.oid),'[\r\n]','<br>','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 
 pg_get_functiondef(pg_proc.oid)~*'^.*is[[:space:]]+not[[:space:]]+distinct[[:space:]]+from.*$' 
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)
ORDER BY routine_schema, routine_name;

Collections where the query belongs to

Collection name	Collection description
Find problems automatically	Queries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .
Find problems by overview	Queries that results point to different aspects of database that might have problems. A human reviewer has to decide based on the results as to whether there are problems or not .

Collection name

Collection description

Find problems automatically

Queries, that results point to problems in the database. Each query in the collection produces an initial assessment. However, a human reviewer has the final say as to whether there is a problem or not .

Find problems by overview

Queries that results point to different aspects of database that might have problems. A human reviewer has to decide based on the results as to whether there are problems or not .

Categories where the query belongs to

Category name	Category description
Performance	Queries of this category provide information about indexes in a database.
User-defined routines	Queries of this category provide information about the user-defined routines

Category name

Category description

Performance

Queries of this category provide information about indexes in a database.

User-defined routines

Queries of this category provide information about the user-defined routines

Reference materials for further reading

Reference
https://philbooth.me/blog/nine-ways-to-shoot-yourself-in-the-foot-with-postgresql (problem 9)
https://modern-sql.com/caniuse/is-distinct-from

Reference

https://philbooth.me/blog/nine-ways-to-shoot-yourself-in-the-foot-with-postgresql (problem 9)

https://modern-sql.com/caniuse/is-distinct-from