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fix: route extended-protocol copy-in termination through Sync - #465
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After a successful extended-protocol COPY FROM STDIN, the connection stayed in `CopyInProgress(true)` state and the client's terminating Sync message was swallowed by the catch-all arm of the state matcher. `on_sync` therefore never ran, `ReadyForQuery` was never sent, and the connection deadlocked: clients built on rust-postgres/tokio-postgres complete the copy with CopyDone followed by Sync, so every extended copy-in froze the connection after its first batch. Two changes, both mirroring PostgreSQL: - after a successful `on_copy_done` in extended mode, transition the connection to `AwaitingSync` so the client's trailing Sync is dispatched to `on_sync`, which sends `ReadyForQuery` and returns the connection to normal operation (this is what the existing comment intended, but the state machine never made the Sync reachable); - a Sync received while the copy is still unfinished (no preceding CopyDone/CopyFail) is rejected with an 08P01 protocol violation, like PostgreSQL rejects any unexpected message type during COPY, instead of being silently discarded. Adds regression tests driving both query protocols over raw TCP: the extended round trip (Sync after CopyDone completes with ReadyForQuery and the connection serves further queries), the mid-copy Sync rejection with connection recovery, and the simple protocol round trip. Without the fix the extended tests fail by timeout, reproducing the deadlock. Signed-off-by: Ning Sun <sunning@greptime.com>
redox
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Sep 28, 2026
rust-postgres pipelines a Sync right after the Execute that starts a COPY FROM STDIN, before any CopyData. Since sunng87#465 that Sync aborted the copy with 08P01, breaking every extended-protocol copy from that client. PostgreSQL ignores Flush and Sync in copy-in mode for exactly this reason. Co-authored-by: Cursor <cursoragent@cursor.com>
sunng87
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Sep 29, 2026
* fix: report the tracked transaction status after simple-protocol COPY FROM STDIN A successful simple-protocol CopyDone always answered ReadyForQuery(Idle), so a COPY run inside BEGIN made clients that track the transaction state from ReadyForQuery believe the transaction had ended. Co-authored-by: Cursor <cursoragent@cursor.com> * fix: ignore Flush and Sync during copy-in, like PostgreSQL rust-postgres pipelines a Sync right after the Execute that starts a COPY FROM STDIN, before any CopyData. Since #465 that Sync aborted the copy with 08P01, breaking every extended-protocol copy from that client. PostgreSQL ignores Flush and Sync in copy-in mode for exactly this reason. Co-authored-by: Cursor <cursoragent@cursor.com> --------- Co-authored-by: Cursor <cursoragent@cursor.com>
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We will only await for
SyncafterCopyDoneis sent from client. Will reject any other messages during the copy.