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Parable implements the read-only subset of Arrow Flight SQL needed to discover Workspace data and execute queries. Clients should inspect GetSqlInfo capability metadata instead of assuming that the server implements every Flight SQL operation.

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Query and metadata commands

GetFlightInfo validates and plans a SQL statement, then returns an opaque ticket. DoGet executes that ticket and streams Arrow record batches.

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Prepared statements

A prepared statement is read-only and has this lifecycle:
  • The CreatePreparedStatement action creates a server-side handle.
  • DoPut on CommandPreparedStatementQuery binds parameter values to it.
  • The ClosePreparedStatement action releases it.
Use prepared statements when query values come from users or another untrusted source. Transactions, savepoints, and prepared writes are not supported.

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Unsupported operations

The SQL surface does not support:
  • Writes, ingestion, or transactions.
  • DoExchange, or DoPut for anything but binding prepared statement parameters.
  • ListFlights or PollFlightInfo.
  • Transaction, savepoint, or cancellation actions.
Unsupported commands return gRPC UNIMPLEMENTED. ListActions returns an empty stream because the server does not advertise actions proactively. Handshake is accepted and does nothing, so JDBC drivers that call it on connect work; authentication comes from the authorization metadata on every call. Primary and foreign-key commands return logical metadata. They do not make the underlying tables enforce constraints.