In addition to the PostgreSQL `SQLITE` type, pglite-fusion provides the `query_sqlite`` function for querying SQLite databases and the `execute_sqlite` function for updating them. Additional functions are listed in the project’s README.
The pglite-fusion extension is written in Rust using the pgrx framework [1].
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Implementation Details
The PostgreSQL `SQLITE` type is stored as a CBOR-encoded `Vec<u8>`. When a query is made, this `Vec<u8>` is written to a random file in the `/tmp` directory. SQLite then loads the file, performs the query, and returns the result as a table containing a single row with an array of JSON-encoded values.
The `execute_sqlite` function follows a similar process. However, instead of returning query results, it returns the contents of the SQLite file (stored in `/tmp`) as a new `SQLITE` instance.
The common path of comparing some constant like the role name to some column in the table is fine, and it's fast enough as the policy checker already has the row in hand when it does the check, but the natural tendency for people to want to abstract their policies into a function like has_permission() will blow up fast.
The best approach I've seen from pyramation's launchql [1] which precomputes policies into a bitstring and then masks that against a query constant bitstring of required permissions. Flexible policy definitions compiled into the row as bits so the check is as fast as possible.