Find derived tables (views and materialized views) that sort rows based on random values but do not limit the number of rows. This is unnecessary because without sorting the rows are returned in a unspecified order. Sorting based on random values is a computationally expensive operation.
Notes
In the returned subquery of view/materialized view 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)
SELECT
table_schema,
table_name,
type,
regexp_replace(view_definition,'[\r\n]',' ','g') AS view_definition
FROM (SELECT
views.table_schema,
views.table_name,
'VIEW' AS type,
views.view_definition
FROM
information_schema.views
WHERE table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
UNION SELECT schemaname, matviewname, 'MATERIALIZED VIEW' AS type, regexp_replace(definition,'[\r\n]',' ','g') AS definition
FROM pg_catalog.pg_matviews) AS foo
WHERE view_definition ~*'order[[:space:]]+by[[:space:]]+[(]random[(][)][)]'
AND view_definition !~*'(limit|fetch[[:space:]]+first)'
ORDER BY table_schema, table_name;
Collections
This query belongs to the following collections:
Name
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
This query is classified under the following categories:
Name
Description
Derived tables
Queries of this category provide information about the derived tables (views, materialized views), which are used to implement virtual data layer.
Performance
Queries of this category provide information about indexes in a database.