Этот запрос перечислит отсутствующие индексы на внешних ключах , исходный источник .
-- check for FKs where there is no matching index
-- on the referencing side
-- or a bad index
WITH fk_actions ( code, action ) AS (
VALUES ( 'a', 'error' ),
( 'r', 'restrict' ),
( 'c', 'cascade' ),
( 'n', 'set null' ),
( 'd', 'set default' )
),
fk_list AS (
SELECT pg_constraint.oid as fkoid, conrelid, confrelid as parentid,
conname, relname, nspname,
fk_actions_update.action as update_action,
fk_actions_delete.action as delete_action,
conkey as key_cols
FROM pg_constraint
JOIN pg_class ON conrelid = pg_class.oid
JOIN pg_namespace ON pg_class.relnamespace = pg_namespace.oid
JOIN fk_actions AS fk_actions_update ON confupdtype = fk_actions_update.code
JOIN fk_actions AS fk_actions_delete ON confdeltype = fk_actions_delete.code
WHERE contype = 'f'
),
fk_attributes AS (
SELECT fkoid, conrelid, attname, attnum
FROM fk_list
JOIN pg_attribute
ON conrelid = attrelid
AND attnum = ANY( key_cols )
ORDER BY fkoid, attnum
),
fk_cols_list AS (
SELECT fkoid, array_agg(attname) as cols_list
FROM fk_attributes
GROUP BY fkoid
),
index_list AS (
SELECT indexrelid as indexid,
pg_class.relname as indexname,
indrelid,
indkey,
indpred is not null as has_predicate,
pg_get_indexdef(indexrelid) as indexdef
FROM pg_index
JOIN pg_class ON indexrelid = pg_class.oid
WHERE indisvalid
),
fk_index_match AS (
SELECT fk_list.*,
indexid,
indexname,
indkey::int[] as indexatts,
has_predicate,
indexdef,
array_length(key_cols, 1) as fk_colcount,
array_length(indkey,1) as index_colcount,
round(pg_relation_size(conrelid)/(1024^2)::numeric) as table_mb,
cols_list
FROM fk_list
JOIN fk_cols_list USING (fkoid)
LEFT OUTER JOIN index_list
ON conrelid = indrelid
AND (indkey::int2[])[0:(array_length(key_cols,1) -1)] @> key_cols
),
fk_perfect_match AS (
SELECT fkoid
FROM fk_index_match
WHERE (index_colcount - 1) <= fk_colcount
AND NOT has_predicate
AND indexdef LIKE '%USING btree%'
),
fk_index_check AS (
SELECT 'no index' as issue, *, 1 as issue_sort
FROM fk_index_match
WHERE indexid IS NULL
UNION ALL
SELECT 'questionable index' as issue, *, 2
FROM fk_index_match
WHERE indexid IS NOT NULL
AND fkoid NOT IN (
SELECT fkoid
FROM fk_perfect_match)
),
parent_table_stats AS (
SELECT fkoid, tabstats.relname as parent_name,
(n_tup_ins + n_tup_upd + n_tup_del + n_tup_hot_upd) as parent_writes,
round(pg_relation_size(parentid)/(1024^2)::numeric) as parent_mb
FROM pg_stat_user_tables AS tabstats
JOIN fk_list
ON relid = parentid
),
fk_table_stats AS (
SELECT fkoid,
(n_tup_ins + n_tup_upd + n_tup_del + n_tup_hot_upd) as writes,
seq_scan as table_scans
FROM pg_stat_user_tables AS tabstats
JOIN fk_list
ON relid = conrelid
)
SELECT nspname as schema_name,
relname as table_name,
conname as fk_name,
issue,
table_mb,
writes,
table_scans,
parent_name,
parent_mb,
parent_writes,
cols_list,
indexdef
FROM fk_index_check
JOIN parent_table_stats USING (fkoid)
JOIN fk_table_stats USING (fkoid)
WHERE table_mb > 9
AND ( writes > 1000
OR parent_writes > 1000
OR parent_mb > 10 )
ORDER BY issue_sort, table_mb DESC, table_name, fk_name;