aiondb-pg-compat

PostgreSQL compatibility layer. Houses the rewrites, parsers, registries, dispatch contracts, and error/message shaping that AionDB applies on top of its native engine to keep PostgreSQL clients and tooling working. The wire-protocol runner lives in aiondb-pgwire and the SQL engine itself lives in aiondb-engine. This crate is the dependency-light home for everything in between, and re-exports the pure scanners from aiondb-pg-syntax.

cargo

[dependencies]
aiondb-pg-compat = { path = "../aiondb-pg-compat" }

modules

module	purpose
`advisory`	classify and parse `pg_advisory_*` calls.
`check_constraints`	parse inline CHECK constraints from `CREATE TABLE`.
`command`	`CompatCommand` baseline tied to `Statement::compat_tag`.
`compat_tag_matrix`	single source of truth for accepted compat tags and their guaranteed behaviour.
`cursor`	`DECLARE CURSOR`, `FETCH`, `MOVE`, `CLOSE`, and `WHERE CURRENT OF` rewrites.
`dispatch`	`PgCompatHooks` trait the engine implements to host the compat layer.
`disposition`	typed classification of statements handed to the compat layer.
`dml_validation`	AST analysis for the WITH-DML rule validator.
`error_catalog`	typed `CompatFailureKind` and stable mapping to `SqlState`.
`metrics`	per-`CompatCommand` counters and parse/bind/execute histograms.
`noop_validation`	reject unknown compat command tags before runtime dispatch.
`oidjoins`	detection and NOTICE extraction for the PG `oidjoins` regression probe.
`prepared`	PREPARE/EXECUTE helpers and type-name normalisation.
`privileges`	map between parser GRANT/REVOKE AST and catalog privilege descriptors.
`registries`	value types for engine-side compat registries (databases, role membership).
`rewrite`	pre-parse text rewrites and small post-parse fix-ups.
`roles`	parsers for `DROP OWNED BY`, `REASSIGN OWNED BY`, `DROP ROLE`.
`startup`	startup parameter whitelist and `options=...` tokenizer.
`state`	versioned compat state (`CompatMiscObjects`, `DomainDefs`, `CastDefs`, `RuleDefs`).
`statement_policy`	per-statement policy gates.
`type_tracking`	parsers for `CREATE TYPE`, `CREATE/ALTER/DROP DOMAIN`.

The pure scanners and parsers from aiondb-pg-syntax are re-exported: do_parsers, do_scan, parsed_commands, prepare, preparse, rule_parsers, scan, type_ref.

key types

item	description
`PgCompatHooks` trait	engine contract used by compat dispatch (in `dispatch`).
`CompatCommand`	active typed compat-command baseline.
`CompatFailureKind`	typed compat error categories with stable `SqlState` mapping.
`CompatObjectFamily`, `CompatObjectKey`	keys used by the persisted compat state.
`COMPAT_STATE_SCHEMA_VERSION`	schema version of the compat state.
`OIDJOINS_EXPECTED_OUTPUT`	snapshot of the PG `oidjoins` expected output, shared with `pg-regress`.
`WITH_DML_RULE_ERROR_PREFIX`	re-export tag prefix used by the WITH-DML rewrite.

example

use aiondb_pg_compat::OIDJOINS_EXPECTED_OUTPUT;
use aiondb_pg_compat::scan::trim_compat_statement;

assert!(!OIDJOINS_EXPECTED_OUTPUT.is_empty());
assert_eq!(trim_compat_statement("SELECT 1;"), "SELECT 1");