Query goal: | Avoid using NOT IN or <>ALL with a non-correlated subquery in PostgreSQL because the query performance will be very poor. |
Notes about the query: | Refers to the column pg_proc.prokind and thus works starting from PostgreSQL 11. 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. 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. The query excludes subqueries with "NOT IN (SELECT DISTINCT" because in this case the DBMS selects an execution plan that has better performance. |
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 |
Fixing suggestion: | Rewrite the query so that it uses NOT EXISTS predicate with correlated subquery. |
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)~*'^.*((?<=not[^;]*)[[:space:]]in|not[[:space:]]*in|<>[[:space:]]*all)[[:space:]]*[(](?=[^)]+select)(?![^)]+distinct)' 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; |
Collection name | Collection description |
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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 . |
Category name | Category description |
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Does not work in some earlier PostgreSQL version | Queries of this category provide information that was not available in some earlier PostgreSQL version |
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 |