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Version: 4.x

PostGraphile best practices

This guide is a work in progress. If you have ideas for best practices, please use the "Suggest improvements to this page" link above to submit them, or discuss them in #documentation on the PostGraphile Discord chat.

Foreign Key Indexes​

PostgreSQL does NOT add indexes to foreign keys by default. This isn't an issue for the forward relation (user_id → user), but for the reverse relation (user → things by user_id) it can make the lookup very expensive. Always add indexes to your foreign keys.

Row Level Security​

If you're using RLS, it's best to enable it on every table in your database. You should at least enable it on every table in your exposed schemas.

Use Table GRANT for SELECT/DELETE and Column GRANT for INSERT/UPDATE​

The following are fine:

-- ✅ Fine
GRANT SELECT ON users TO graphql_role;
-- ✅ Fine
GRANT INSERT (column_1, column_2, ...) ON users TO graphql_role;
-- ✅ Fine
GRANT UPDATE (column_a, column_b, ...) ON users TO graphql_role;
-- ✅ Fine
GRANT DELETE ON users TO graphql_role;

The following should be avoided:

-- 🛑 DO NOT USE
GRANT SELECT (column_a, column_b) ON users TO graphql_role;
-- 🛑 DO NOT USE
GRANT INSERT ON users TO graphql_role;
-- 🛑 DO NOT USE
GRANT UPDATE ON users TO graphql_role;

Column-level SELECT grants cause a lot of issues:

  • Reduces the number of optimisations we can do
  • Cannot SELECT * FROM
  • Cannot use RETURNING * (e.g. what we do in CRUD operations currently)
  • Cannot pass a row type into a function (like we do for computed columns)

Table-level INSERT/UPDATE grants are not advisable because they lack the explicitness that should come from such operations.

Simplify Your GraphQL Field Names​

You can get a leg up on this using @graphile-contrib/pg-simplify-inflector. The long names PostGraphile uses by default are to try and avoid people getting naming conflicts when they run PostGraphile for the first time. Once you're more comfortable you should move to using shorter names as it's a GraphQL best practice.

(Scan the docs for [RECOMMENDED], but take a moment to understand why they're recommended and yet not enabled by default - they often require greater knowledge of PostGraphile and your database.)

Protect Your API​

See Production Considerations.

Use LANGUAGE sql Over LANGUAGE plpgsql Where Possible​

Performance reasons. Specifically, under many circumstances, functions in SQL (but not plpgsql) can be inlined into the call-site and are thereby transparent to the query planner. The PostgreSQL docs have a lot more details.

Name Triggers With A Numeric Prefix​

e.g. _200_do_a_thing / _800_do_something_else

Reason: triggers in PostgreSQL run in lexicographical order.