Do not cause a potential performance bottleneck by having a shared resource. By having a shared sequence it is not possible to change properties of sequences of different tables independently (for instance the owner column or step), i.e., it increases coupling between tables. By having a shared sequence it is impossible to specify the owner (table column) to the sequence generator.
Notes
In case of the string_agg function, the line break (br) tag is used as a part of the separator 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)
WITH serial_columns AS (SELECT c.table_schema, t.table_type, c.table_name , c.column_name, coalesce(c.column_default, d.domain_default) AS column_default
FROM information_schema.columns c LEFT JOIN information_schema.domains d USING (domain_schema, domain_name)
INNER JOIN information_schema.schemata s ON c.table_schema=s.schema_name
INNER JOIN information_schema.tables t USING (table_schema, table_name)
WHERE coalesce (c.column_default, d.domain_default) LIKE 'nextval%'
AND (c.table_schema = 'public'
OR s.schema_owner<>'postgres')),
sequences AS (SELECT sc.table_schema, sc.table_type, sc.table_name , sc.column_name, s.sequence_schema, s.sequence_name
FROM serial_columns AS sc, information_schema.sequences AS s
WHERE column_default ILIKE '%' || 'nextval(''' || s.sequence_name || '''::regclass)' || '%' OR
column_default='nextval(''' || s.sequence_schema || '.' || s.sequence_name || '''::regclass)')
SELECT sequence_schema, sequence_name, Count(*) AS number_of_uses, string_agg(table_type || ': ' || table_schema || '.' || table_name || '.' || column_name, '; ' ORDER BY table_schema, table_name) AS columns
FROM sequences
GROUP BY sequence_schema, sequence_name
HAVING Count(*)>1
ORDER BY sequence_schema, sequence_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
Comfortability of data management
Queries of this category provide information about the means that have been used to make the use or management of database more comfortable and thus, more efficient.
Default value
Queries of this catergory provide information about the use of default values.
Performance
Queries of this category provide information about indexes in a database.
Sequence generators
Queries of this category provide information about sequence generators and their usage.