Fix SELECT on tables with bytea columns hanging in process worker#171
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Maxteabag merged 1 commit intoMaxteabag:mainfrom Apr 18, 2026
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psycopg2 returns memoryview objects for bytea columns which cannot be pickled through multiprocessing.Pipe. The worker's send() silently swallowed the serialization error, leaving the client waiting forever. Convert memoryview to bytes in CursorBasedAdapter.execute_query() before rows are returned, so they can be safely pickled. Fixes Maxteabag#161
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#161's symptom was an indefinite spinner: psycopg2 returned memoryview for bytea, which couldn't be pickled across multiprocessing.Pipe. _WorkerState.send caught the exception and silently dropped it, so the client's recv() waited forever. #171 fixed the specific memoryview case at the adapter, but the silent swallow is still a trap for any other non-picklable cell type a future driver might return. Narrow the catch: on pickle errors, replace the payload with an error message (keyed to the original query id) so the client surfaces it. Tests pin the scenarios that were previously gaps: - CursorBasedAdapter.execute_query actually calls _sanitize_row (guards against a future revert of the call site). - Sanitized rows round-trip through pickle. - _WorkerState.send with a non-picklable payload delivers an error message within a short timeout. - Picklable payloads still pass through unchanged.
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Summary
memoryviewobjects forbyteacolumns which cannot be pickled throughmultiprocessing.Pipesend()silently swallowed the serialization error, leaving the client waiting forever (spinner)memoryviewtobytesinCursorBasedAdapter.execute_query()before rows are returned, so they can be safely pickledTest plan
_sanitize_celland_sanitize_rowpassSELECT * FROM bytea_repro;as single statement — should return 3 rows immediatelySELECT id, name FROM bytea_repro;— should still workFixes #161