Message-ID: <gh-pgjdbc-pgjdbc-3642@github.com>
From: "eirikbakke (@eirikbakke)" <noreply+eirikbakke@github.com>
To: "pgjdbc/pgjdbc" <noreply+pgjdbc-pgjdbc@github.com>
Date: Wed, 28 May 2025 19:45:05 +0000
Subject: [pgjdbc/pgjdbc] issue #3642: Calcutta/Kolkata time zone name mismatch prevents connection
List-Id: <gh-pgjdbc-pgjdbc.github.com>
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X-GitHub-Issue: 3642
X-GitHub-Repo: pgjdbc/pgjdbc
X-GitHub-State: closed
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X-GitHub-Url: https://github.com/pgjdbc/pgjdbc/issues/3642
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**Describe the issue**

If a user with a Java client version that runs with the time zone "Asia/Calcutta" connects to a PostgreSQL server that uses the newer equivalent name "Asia/Kolkata" for the same time zone, the following exception is seen:

```
org.postgresql.util.PSQLException: FATAL: invalid value for parameter "TimeZone": "Asia/Calcutta"
  at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2725)
  at org.postgresql.core.v3.QueryExecutorImpl.readStartupMessages(QueryExecutorImpl.java:2837)
  at org.postgresql.core.v3.QueryExecutorImpl.<init>(QueryExecutorImpl.java:175)
  at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:317)
  at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:54)
  at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:273)
  at org.postgresql.Driver.makeConnection(Driver.java:446)
  at org.postgresql.Driver.connect(Driver.java:298)
```

I suspect the same can happen with mismatches between "Europe/Kiev" and "Europe/Kyiv" as well (another recent name change I have seen in time zone databases).

The relevant JDBC driver code is in `org.postgresql.core.v3.ConnectionFactoryImpl.createPostgresTimeZone()`. For the time zones "Asia/Calcutta", "Asia/Kolkata", "Europe/Kiev", and "Europe/Kyiv", it would probably be better to generate an offset-based time zone name that works regardless of server version and distribution. Or if it's not possible to pass offset-based time zone names for the TimeZone connection parameter, perhaps pass "GMT" instead and automatically call "SET SESSION TIME ZONE INTERVAL" to set the offset instead.

**Driver Version?** 

42.7.3

**Java Version?**

21.0.4

**OS Version?**

Windows

**PostgreSQL Version?**

Unknown (bug was reported by a user of my database UI product, [Ultorg](https://www.ultorg.com/)).

**To Reproduce**

Use a PostgreSQL server that uses the newer "Asia/Kolkata" time zone name. For the client, use OpenJDK 21.0.4 for Windows which uses the older "Asia/Calcutta". Then set the machine time zone to India time and attempt to connect.

**Expected behaviour**

The connection should succeed, but does not.

**Logs**

See the earlier-pasted stack trace.