Forked from jonasraoni/pgsql-find-create-missing-indexes.sql
Created
July 17, 2023 10:41
-
-
Save mhicauber/6e06c6cf55d6a86cbc1f418d8013c3fc to your computer and use it in GitHub Desktop.
PostgreSQL SELECT statement to find/create foreign keys that are missing indexes
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
-- find missing indexes | |
SELECT | |
conrelid::regclass, conname, reltuples::bigint | |
FROM | |
pg_constraint | |
JOIN pg_class | |
ON conrelid = pg_class.oid | |
WHERE | |
contype = 'f' | |
AND NOT EXISTS ( | |
SELECT 1 | |
FROM | |
pg_index | |
WHERE | |
indrelid = conrelid | |
AND ( | |
SELECT | |
ARRAY( | |
SELECT | |
conkey[i] | |
FROM | |
generate_series(array_lower(conkey, 1), array_upper(conkey, 1)) i | |
ORDER BY | |
1 | |
) | |
) = ( | |
SELECT | |
ARRAY( | |
SELECT | |
indkey[i] | |
FROM | |
generate_series(array_lower(indkey, 1), array_upper(indkey, 1)) i | |
ORDER BY | |
1 | |
) | |
) | |
) | |
ORDER BY | |
reltuples DESC | |
-- generate statements | |
SELECT 'CREATE INDEX idx_' || table_name || '_' || column_name || ' ON ' | |
|| foreign_schema || '.' || table_name || '(' || column_name || ');' | |
FROM ( | |
SELECT | |
n.nspname AS schema, | |
cl.relname AS table_name, | |
a.attname AS column_name, | |
ct.conname AS key_name, | |
nf.nspname AS foreign_schema, | |
clf.relname AS foreign_table_name, | |
af.attname AS foreign_column_name, | |
pg_get_constraintdef(ct.oid) AS create_sql | |
FROM | |
pg_catalog.pg_attribute a | |
JOIN pg_catalog.pg_class cl | |
ON a.attrelid = cl.oid AND cl.relkind = 'r' | |
JOIN pg_catalog.pg_namespace n | |
ON n.oid = cl.relnamespace | |
JOIN pg_catalog.pg_constraint ct | |
ON a.attrelid = ct.conrelid | |
AND ct.confrelid != 0 | |
AND ct.conkey[1] = a.attnum | |
JOIN pg_catalog.pg_class clf | |
ON ct.confrelid = clf.oid | |
AND clf.relkind = 'r' | |
JOIN pg_catalog.pg_namespace nf | |
ON nf.oid = clf.relnamespace | |
JOIN pg_catalog.pg_attribute af | |
ON af.attrelid = ct.confrelid | |
AND af.attnum = ct.confkey[1] | |
) X |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment