Message-ID: <gh-pgjdbc-pgjdbc-3837-c3562265852@github.com>
From: "m-van-tilburg (@m-van-tilburg)" <noreply+m-van-tilburg@github.com>
To: "pgjdbc/pgjdbc" <noreply+pgjdbc-pgjdbc@github.com>
Date: Fri, 21 Nov 2025 09:58:05 +0000
Subject: Re: [pgjdbc/pgjdbc] issue #3837: ResultSet.getTimestamp() returns incorrect point in time for historical dates
In-Reply-To: <gh-pgjdbc-pgjdbc-3837@github.com>
References: <gh-pgjdbc-pgjdbc-3837@github.com>
List-Id: <gh-pgjdbc-pgjdbc.github.com>
X-GitHub-Author-Login: m-van-tilburg
X-GitHub-Comment-Id: 3562265852
X-GitHub-Comment-Type: issue_comment
X-GitHub-Issue: 3837
X-GitHub-Repo: pgjdbc/pgjdbc
X-GitHub-Type: comment
X-GitHub-Url: https://github.com/pgjdbc/pgjdbc/issues/3837#issuecomment-3562265852
Content-Type: text/plain; charset=utf-8

The current `pgjdbc` code is incorrect because instances of `java.util.Calendar` are created (for example with `Calendar.getInstance()` or `new GregorianCalendar()`) without making the calendar pure (proleptic) Gregorian using `java.util.GregorianCalendar#setGregorianChange(java.util.Date)`. The currently created calendar instances are a hybrid of the Julian and Gregorian calendar which is usually not appropriate in a JDBC driver, they should be pure (proleptic) Gregorian instead (to match what is described in https://www.postgresql.org/docs/17/datetime-units-history.html).