Message-ID: <gh-pgjdbc-pgjdbc-3979@github.com>
From: "vlsi (@vlsi)" <noreply+vlsi@github.com>
To: "pgjdbc/pgjdbc" <noreply+pgjdbc-pgjdbc@github.com>
Date: Fri, 20 Mar 2026 19:29:16 +0000
Subject: [pgjdbc/pgjdbc] PR #3979: fix: fix flaky CopyBothResponseTest by using WAL flush LSN
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X-GitHub-Issue: 3979
X-GitHub-Labels: building-and-testing
X-GitHub-Repo: pgjdbc/pgjdbc
X-GitHub-State: merged
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X-GitHub-Url: https://github.com/pgjdbc/pgjdbc/pull/3979
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Similar to 2a7ac4140 which fixed flaky replication restart tests in LogicalReplicationTest by waiting for confirmed_flush_lsn.

It should fix failure like

https://github.com/pgjdbc/pgjdbc/actions/runs/23354694589/job/67942890085?pr=3844

```
FAILURE   0,2sec, org.postgresql.replication.CopyBothResponseTest > receiveXLogData()
    org.postgresql.util.PSQLException: ERROR: requested starting point 0/B626000 is ahead of the WAL flush position of this server 0/B622000
        at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2895)
        at org.postgresql.core.v3.QueryExecutorImpl.processCopyResults(QueryExecutorImpl.java:1434)
        at org.postgresql.core.v3.QueryExecutorImpl.readFromCopy(QueryExecutorImpl.java:1330)
        at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImpl.java:49)
        at org.postgresql.core.v3.CopyDualImpl.readFromCopy(CopyDualImpl.java:43)
        at org.postgresql.replication.CopyBothResponseTest.receiveXLogData(CopyBothResponseTest.java:144)
```