g corresponding remote subtransactions. When multiple remote
    transactions are involved in the current local transaction, by default
    <code class="filename">postgres_fdw</code> commits or aborts those remote
    transactions serially when the local transaction is committed or aborted.
    When multiple remote subtransactions are involved in the current local
    subtransaction, by default <code class="filename">postgres_fdw</code> commits or
    aborts those remote subtransactions serially when the lo