This reverts commits 24c35ec and 57169ad. PreRestoreCommand() and
PostRestoreCommand() need to be put closer to the system() call calling
a restore_command, as they enable in_restore_command for the startup
process which would in turn trigger an immediate proc_exit() in the
SIGTERM handler. Perhaps we could get rid of this behavior entirely,
but 24c35ec has made the window where the flag is enabled much larger
than it was, and any Postgres-like actions (palloc, etc.) taken by code
paths while the flag is enabled could lead to more severe issues in the
shutdown processing.
Note that curculio has showed that there are much more problems in this
area, unrelated to this change, actually, hence the issues related to
that had better be addressed first. Keeping the code of HEAD in line
with the stable branches should make that a bit easier.
Per discussion with Andres Freund and Nathan Bossart.
Discussion: https://postgr.es/m/Y979NR3U5VnWrTwB@paquier.xyz
Presently, restore_command uses a different code path than
archive_cleanup_command and recovery_end_command. These code paths
are similar and can be easily combined, as long as it is possible to
identify if a command should:
- Issue a FATAL on signal.
- Exit immediately on SIGTERM.
While on it, this removes src/common/archive.c and its associated
header. Since the introduction of c96de2c, BuildRestoreCommand() has
become a simple wrapper of replace_percent_placeholders() able to call
make_native_path(). This simplifies shell_restore.c as long as
RestoreArchivedFile() includes a call to make_native_path().
Author: Nathan Bossart
Reviewed-by: Andres Freund, Michael Paquier
Discussion: https://postgr.es/m/20221227192449.GA3672473@nathanxps13
There are a number of places where a shell command is constructed with
percent-placeholders (like %x). It's cumbersome to have to open-code
this several times. This factors out this logic into a separate
function. This also allows us to ensure consistency for and document
some subtle behaviors, such as what to do with unrecognized
placeholders.
The unified handling is now that incorrect and unknown placeholders
are an error, where previously in most cases they were skipped or
ignored. This affects the following settings:
- archive_cleanup_command
- archive_command
- recovery_end_command
- restore_command
- ssl_passphrase_command
The following settings are part of this refactoring but already had
stricter error handling and should be unchanged in their behavior:
- basebackup_to_shell.command
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5238bbed-0b01-83a6-d4b2-7eb0562a054e%40enterprisedb.com
restore_command has only been used until now by the backend, but there
is a pending patch for pg_rewind to make use of that in the frontend.
Author: Alexey Kondratov
Reviewed-by: Andrey Borodin, Andres Freund, Alvaro Herrera, Alexander
Korotkov, Michael Paquier
Discussion: https://postgr.es/m/a3acff50-5a0d-9a2c-b3b2-ee36168955c1@postgrespro.ru
Michael Paquier
Peter Eisentraut
Bruce Momjian