7f3381c7ee
When the backend reads COPY data, it ignores all sync messages, as per c01641f8aed0. With psql pipelines, it is possible to manually send sync messages with \sendpipeline which leaves the frontend in an unrecoverable state as the backend will not send the necessary ReadyForQuery message that is expected to feed psql result consumption logic. It could be possible to artificially reduce the piped_syncs and requested_results, however libpq's state would still have queued sync messages in its command queue, and the only way to consume those without directly calling pqCommandQueueAdvance() is to process ReadyForQuery messages that won't be sent since the backend ignores these. Perhaps this could be improved in the future, but I am not really excited about introducing this amount of complications in libpq to manipulate the message queues without a better use case to support it. Hence, this patch aborts the connection if we detect excessive sync messages after a COPY in a pipeline to avoid staying in an inconsistent protocol state, which is the best thing we can do with pipelines in psql for now. Note that this change does not prevent wrapping a set of queries inside a block made of \startpipeline and \endpipeline, only the use of \syncpipeline for a COPY. Reported-by: Nikita Kalinin <n.kalinin@postgrespro.ru> Author: Anthonin Bonnefoy <anthonin.bonnefoy@datadoghq.com> Discussion: https://postgr.es/m/18944-8a926c30f68387dd@postgresql.org
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
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