WIP: Implement COPY … FROM STDIN
#566
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This is still WIP. To do items include: - [ ] Test the various error cases, I have mostly focused on the success case so far - [ ] Test the backpressure support - [ ] Change the public API to accept the table + columns to copy into as well as options so that we can build the `COPY` query instead of letting the user write it - [ ] Add an API that allows binary transfer of data
fabianfett
reviewed
Jun 24, 2025
| /// A handle to send | ||
| public struct PostgresCopyFromWriter: Sendable { | ||
| private let channelHandler: NIOLoopBound<PostgresChannelHandler> | ||
| private let context: NIOLoopBound<ChannelHandlerContext> |
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use the handlerContext: ChannelHandlerContext? with ! in PostgresChannelHandler instead.
fabianfett
reviewed
Jun 24, 2025
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| func executeImmediatelyOrSchedule(_ task: @Sendable @escaping () -> Void) { | ||
| if inEventLoop { | ||
| return task() | ||
| } | ||
| return execute(task) | ||
| } |
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this needs to allocate even in the fast path. we don't like that.
fabianfett
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Jun 24, 2025
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| struct NotWritableError: Error, CustomStringConvertible { | ||
| var description = "No data must be written to `PostgresCopyFromWriter` after it has sent a CopyDone or CopyFail message, ie. after the closure producing the copy data has finished" | ||
| } |
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this isn't used anywhere.
fabianfett
reviewed
Jun 24, 2025
| // TODO: Write doc comment | ||
| public func copyFrom( | ||
| _ query: PostgresQuery, | ||
| writeData: @escaping @Sendable (PostgresCopyFromWriter) async throws -> Void, |
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closure should be last argument.
fabianfett
reviewed
Jun 24, 2025
| } | ||
| self.avoidingStateMachineCoW { state in | ||
| state = .copyingData(.readyToSend) | ||
| continuation.resume() |
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side effect triggered in state machine. return the continuation out and succeed it in the PostgresChannelHandler.
fabianfett
reviewed
Jun 24, 2025
| @@ -88,7 +88,23 @@ struct ConnectionStateMachine { | |||
| case sendParseDescribeBindExecuteSync(PostgresQuery) | |||
| case sendBindExecuteSync(PSQLExecuteStatement) | |||
| case failQuery(EventLoopPromise<PSQLRowStream>, with: PSQLError, cleanupContext: CleanUpContext?) | |||
| /// Fail a query's execution by throwing an error on the given continuation. | |||
| case failQueryContinuation(any AnyErrorContinuation, with: PSQLError, cleanupContext: CleanUpContext?) | |||
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existential, where Existential isn't necessary.
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This is still WIP. To do items include:
COPYquery instead of letting the user write itPostgresCopyFromWriterto reduce the number ofCopyDatamessages we need to send (and thus the protocol overhead). Alternatively, we can leave that kind of optimization to the client.Fixes #290