From: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com> |
---|---|
To: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | recovery starting when backup_label exists, but not recovery.signal |
Date: | 2019-09-24 05:25:03 |
Message-ID: | CAHGQGwEYYg_Ng+03FtZczacCpYgJ2Pn=B_wPtWF+FFLYDgpa1g@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Hi,
When backup_label exists, the startup process enters archive recovery mode
even if recovery.signal file doesn't exist. In this case, the startup process
tries to retrieve WAL files by using restore_command. Then, at the beginning
of the archive recovery, the contents of backup_label are copied to pg_control
and backup_label file is removed. This would be an intentional behavior.
But I think the problem is that, if the server shuts down during that
archive recovery, the restart of the server may cause the recovery to fail
because neither backup_label nor recovery.signal exist and the server
doesn't enter an archive recovery mode. Is this intentional, too? Seems No.
So the problematic scenario is;
1. the server starts with backup_label, but not recovery.signal.
2. the startup process enters an archive recovery mode because
backup_label exists.
3. the contents of backup_label are copied to pg_control and
backup_label is deleted.
4. the server shuts down..
5. the server is restarted. neither backup_label nor recovery.signal exist.
6. the startup process starts just crash recovery because neither backup_label
nor recovery.signal exist. Since it cannot retrieve WAL files from archival
area, it may fail.
One idea to fix this issue is to make the above step #3 remember that
backup_label existed, in pg_control. Then we should make the subsequent
recovery enter an archive recovery mode if pg_control indicates that
even if neither backup_label nor recovery.signal exist. Thought?
Regards,
--
Fujii Masao
From | Date | Subject | |
---|---|---|---|
Next Message | David Fetter | 2019-09-24 05:26:21 | Re: Efficient output for integer types |
Previous Message | Michael Paquier | 2019-09-24 05:21:40 | Re: Memory Accounting |