FOR UPDATE is not needed if there is no FROM clause in the SELECT statement

Query goal:

Find routines that use SELECT … FOR UPDATE without selecting rows from a specific table. For instance: SELECT 'text' AS v FOR UPDATE;

Query type:

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

Query reliability:

Medium (Medium number of false-positive results)

Query license:

MIT License

Fixing suggestion:

Drop the routine and recreate it.

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( regexp_replace(pg_get_functiondef(pg_proc.oid),'<','&lt','g'),'[\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_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 pg_get_functiondef(pg_proc.oid)~*'[[:space:]]select[[:space:]][^;]+for[[:space:]]+update[[:space:]]*[;]' 
AND pg_get_functiondef(pg_proc.oid)!~*'[[:space:]]select[[:space:]][^;]*[[:space:]]from[[:space:]][^;]*for[[:space:]]+update[[:space:]]*[;]'
ORDER BY routine_schema, routine_name, parameters;

SQL statements for generating SQL statements that help us to fix the problem

SQL query	Description
WITH unnecessary_for_update AS (SELECT pg_namespace.nspname AS routine_schema, pg_proc.proname AS routine_name, pg_get_function_identity_arguments(pg_proc.oid) AS parameters 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_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 pg_get_functiondef(pg_proc.oid)~'[[:space:]]select[[:space:]][^;]+for[[:space:]]+update[[:space:]][;]' AND pg_get_functiondef(pg_proc.oid)!~'[[:space:]]select[[:space:]][^;][[:space:]]from[[:space:]][^;]for[[:space:]]+update[[:space:]][;]') SELECT format('DROP ROUTINE %1$s.%2$s(%3$s);', routine_schema, routine_name, parameters) AS statements FROM unnecessary_for_update ORDER BY routine_schema, routine_name, parameters;	Drop the routine.

SQL query

Description

WITH unnecessary_for_update AS (SELECT 
  pg_namespace.nspname AS routine_schema, 
  pg_proc.proname AS routine_name, 
  pg_get_function_identity_arguments(pg_proc.oid) AS parameters
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_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 pg_get_functiondef(pg_proc.oid)~*'[[:space:]]select[[:space:]][^;]+for[[:space:]]+update[[:space:]]*[;]' 
AND pg_get_functiondef(pg_proc.oid)!~*'[[:space:]]select[[:space:]][^;]*[[:space:]]from[[:space:]][^;]*for[[:space:]]+update[[:space:]]*[;]')
SELECT format('DROP ROUTINE %1$s.%2$s(%3$s);', routine_schema, routine_name, parameters) AS statements
FROM unnecessary_for_update
ORDER BY routine_schema, routine_name, parameters;

Drop the routine.

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 .

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 .

Categories where the query belongs to

Category name	Category description
Concurrency control	Queries of this category provide information about concurrency control.
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

Category name

Category description

Concurrency control

Queries of this category provide information about concurrency control.

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