Queries

In general, READ ONLY queries are supported. You cannot write directly to object storage. This includes all Postgres built-in functions, statements and types. It also includes any of those provided by EPAS or PGE, depending on which distribution you choose to deploy.

In general, you cannot insert, update, delete or otherwise modify data. You can use CREATE TABLE but only to create a normal Postgres table on the node, bearing in mind that the node is ephemeral and will be destroyed when you terminate it. You can also CREATE TABLE... USING PGAA to create an external table that references Delta Tables in S3-compatible object storage. You must load data into the bucket out-of-band, either with your own ETL scripts or with Lakehouse Sync.
See Loading Data for more details.

One exception is Postgres system tables, such as those used for storing users, roles, and grants. These tables are stored on the local block device, which is included in backups and restores. So you can CREATE USER or CREATE ROLE or GRANT USAGE, and these users/roles/grants will survive restarts and restores.