PostgreSQL and MySQL clients

Transit accepts selected PostgreSQL and MySQL wire protocols through its SQL gateway. Both adapters use the same account runtime, catalog, Fuze execution and durable operation ledger as native SQL sessions. They do not run either upstream database engine or provide its complete SQL dialect.

Follow Connect with psql and mysql for runnable configuration and login examples. The gateway application owns standalone configuration; the wire contract owns exact messages, admission rules and limits.

Listeners and accounts

transit server starts PostgreSQL and MySQL listeners only when their ports are configured. There is no implicit PostgreSQL or MySQL port. Local server listeners bind IPv4 loopback; their accounts explicitly select trust or password authentication and need native login and database grants. The native console's Unix peer account does not implicitly enable TCP login.

Local development can set sql.tls.mode: disabled and use an enabled trust account. Trust accepts the configured SQL account name asserted by the client; it does not verify the client's operating-system user. Password authentication uses PostgreSQL SCRAM-SHA-256 over either permitted transport. MySQL password authentication requires TLS for its full caching_sha2_password exchange.

Standalone gateway TLS defaults to required. The three modes are disabled, optional and required. Optional mode requires valid TLS material before binding and permits encrypted or plaintext startup; required mode rejects plaintext. TLS negotiation failures never trigger an automatic downgrade. Remote exposure also requires explicit host, certificate and account configuration.

Supported queries and types

Surface	Supported boundary
SQL execution	Autocommit general-Table SELECT, CREATE TABLE, INSERT, UPDATE and DELETE
Parameters	Typed single-Table SELECT and mutations; the owning compiler imposes its plan limits
Relational reads	Selected literal int64 joins and grouping in the relational profile
Values	int64, uint64, finite float64, Boolean, UTF-8, binary and SQL NULL
PostgreSQL extended protocol	Prepared reads and suspended read portals; a write requires exactly one Execute followed by Sync
MySQL prepared statements	Bounded classic-protocol preparation, typed execution and explicit handle cleanup

PostgreSQL exposes uint64 as numeric(20,0); MySQL uses unsigned LONGLONG. PostgreSQL text cannot contain NUL. Missing, type-error and conflict cells cannot be encoded as SQL NULL. Nested, decimal and other native logical descriptors outside these six types reject at the wire boundary. Each UTF-8 or binary bound parameter is limited to 4096 bytes, independently of frame size.

Transactions, savepoints, disabling autocommit, multi-statement requests, ALTER/DROP, RETURNING, COPY, bulk upload, replication and arbitrary upstream system catalogs are unsupported. The console's native statement/type profile is broader; parser acceptance in the common grammar does not widen a wire adapter's execution profile.

PostgreSQL writes are held until the complete permitted extended cycle has arrived. A write followed by Flush rejects before dispatch. Suspended read portals retain their original snapshot; continuing a portal never silently opens a newer one. MySQL reset releases temporary handles and session state, without undoing previously admitted account work.

Timeouts, disconnection and recovery

Idle PostgreSQL/MySQL connections remain open by default: sql.idle_ms is zero. A positive value sets an idle timeout between complete commands. Expiry reports PostgreSQL FATAL 57P05 or MySQL error 4031 / SQLSTATE HY000, then closes the connection. Handshake, partial-frame, command and output deadlines remain finite. The native HTTP session lease is a separate setting.

The default gateway limits include 64 connections, eight per account, 16 prepared statements and four portals per session, with a 16 MiB session allocator budget. Wire SQL text is at most 4096 bytes. Interactive reads admit at most 10,000 output rows, 16 MiB of result bytes and 10,000 native requests; relational execution has separate bounded work and spill. The wire contract lists configurable ceilings.

Current account credentials, role and object permissions govern metadata, rows and terminal counts. An unavailable authority prevents disclosure. A socket failure, deadline or cancellation cannot establish rollback of accepted work. The PostgreSQL/MySQL protocols do not carry the native admission token: submitting the SQL again creates new work. Inspect the original operation through the account's recovery controls when a mutation outcome is uncertain.