Thread

Re: Patch for migration of the pg_commit_ts directory

ls7777 <ls7777@yandex.ru> — 2026-05-29T16:08:56Z

<div>Hi,</div><div> </div><div><div>During copying, the copy_subdir_files function cleans up the target directory with the remove_new_subdir(new_subdir, true) function.</div><div> </div></div><div><br /></div><div><br /></div><div>----------------</div>
                        <div>Кому: 'ls7777' (ls7777@yandex.ru);<br /></div>
                        <div>Копия: pgsql-hackers@postgresql.org, orlovmg@gmail.com, amit.kapila16@gmail.com, Masahiko Sawada (sawada.mshk@gmail.com);<br /></div>
                        <div>Тема: Patch for migration of the pg_commit_ts directory;<br /></div>
                        <div>27.05.2026, 10:25, "Hayato Kuroda (Fujitsu)" &lt;kuroda.hayato@fujitsu.com&gt;:<br /></div>
                        <blockquote><p>Dear Sergey,<br /><br />While considering the feature once again, I came up with another issue.<br /><br />When pg_upgrade migrates objects to a new instance, it normally checks whether<br />the new instance does not have existing objects. E.g., check_new_cluster_is_empty()<br />checks if no tables exist, and check_new_cluster_replication_slots() ensures<br />there are no logical slots.<br /><br />Based on that, how should we handle the commit timestamp? Since the patch simply<br />copies the pg_commit_ts subdir, existing entries in the new cluster will be overwritten.<br />So we may have to check if the commit_ts entries are empty when the pg_upgrade<br />command runs, but not sure how to do that.<br /><br />Best regards,<br />Hayato Kuroda<br />FUJITSU LIMITED<br /> <br /></p></blockquote>