Message-ID: <gh-pgjdbc-pgjdbc-4014@github.com>
From: "bilalshehata (@bilalshehata)" <noreply+bilalshehata@github.com>
To: "pgjdbc/pgjdbc" <noreply+pgjdbc-pgjdbc@github.com>
Date: Thu, 09 Apr 2026 07:00:45 +0000
Subject: [pgjdbc/pgjdbc] PR #4014: fix: restore pre-describe for generated-key batches
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Commit [d232e605](https://github.com/pgjdbc/pgjdbc/commit/d232e605de960f3a8ca2dfef4974dbe546b860bb) removed the pre-describe step from internalExecuteBatch for queries with wantsGeneratedKeysAlways. Without it the driver cannot estimate result row sizes before pipelining, so flushIfDeadlockRisk falls back to 250 bytes per query. For INSERT ... RETURNING with large columns the actual response is orders of magnitude larger, overflowing TCP buffers and causing client/server deadlock.


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