remove a separate index for the name column #467
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*Note:* I tested with Postgres only. Run an `EXPLAIN` query:
```
> Role.where(name: 'Admin').explain
Role Load (0.5ms) SELECT "roles".* FROM "roles" WHERE "roles"."name" = $1 [["name", "Admin"]]
=> EXPLAIN for: SELECT "roles".* FROM "roles" WHERE "roles"."name" = $1 [["name", "Admin"]]
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------
Bitmap Heap Scan on roles (cost=4.17..11.28 rows=3 width=96)
Recheck Cond: ((name)::text = 'Admin'::text)
-> Bitmap Index Scan on index_roles_on_name_and_resource_type_and_resource_id (cost=0.00..4.17 rows=3 width=0)
Index Cond: ((name)::text = 'Admin'::text)
(4 rows)
```
https://github.com/ankane/pghero adds this index to the Duplicate Indexes section.
On roles
`index_roles_on_name (name)`
is covered by
`index_roles_on_name_and_resource_type_and_resource_id (name, resource_type, resource_id)`
1 similar comment
|
I tested with other databases and it appears the index is not needed with Postgres only. Look at https://github.com/sergey-alekseev/test-rolify. |
2 similar comments
EppO
approved these changes
Nov 18, 2017
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Note: I tested with Postgres only. Run an
EXPLAINquery:https://github.com/ankane/pghero adds this index to the Duplicate Indexes section.
On roles
index_roles_on_name (name)is covered by
index_roles_on_name_and_resource_type_and_resource_id (name, resource_type, resource_id)