database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-02 09:02:37 +03:00
Code Activity

Remove InitXLOGAccess().

Browse Source 
It's not great that RecoveryInProgress() calls InitXLOGAccess(),
because a status inquiry function typically shouldn't have the side
effect of performing initializations. We could fix that by calling
InitXLOGAccess() from some other place, but instead, let's remove it
altogether.

One thing InitXLogAccess() did is initialize wal_segment_size, but it
doesn't need to do that. In the postmaster, PostmasterMain() calls
LocalProcessControlFile(), and all child processes will inherit that
value -- except in EXEC_BACKEND bulds, but then each backend runs
SubPostmasterMain() which also calls LocalProcessControlFile().

The other thing InitXLOGAccess() did is update RedoRecPtr and
doPageWrites, but that's not critical, because all code that uses
them will just retry if it turns out that they've changed. The
only difference is that most code will now see an initial value that
is definitely invalid instead of one that might have just been way
out of date, but that will only happen once per backend lifetime,
so it shouldn't be a big deal.

Patch by me, reviewed by Nathan Bossart, Michael Paquier, Andres
Freund, Heikki Linnakangas, and Álvaro Herrera.

Discussion: http://postgr.es/m/CA+TgmoY7b65qRjzHN_tWUk8B4sJqk1vj1d31uepVzmgPnZKeLg@mail.gmail.com
This commit is contained in:
Robert Haas
2021-12-13 09:58:36 -05:00
parent 64da07c41a
commit fa0e03c15a
4 changed files with 22 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/backend/utils/init/postinit.c
View File

@ -624,25 +624,14 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
}
/*
* Initialize local process's access to XLOG.
* If this is either a bootstrap process nor a standalone backend, start
* up the XLOG machinery, and register to have it closed down at exit.
* In other cases, the startup process is responsible for starting up
* the XLOG machinery, and the checkpointer for closing it down.
*/
if (IsUnderPostmaster)
if (!IsUnderPostmaster)
{
/*
* The postmaster already started the XLOG machinery, but we need to
* call InitXLOGAccess(), if the system isn't in hot-standby mode.
* This is handled by calling RecoveryInProgress and ignoring the
* result.
*/
(void) RecoveryInProgress();
}
else
{
/*
* We are either a bootstrap process or a standalone backend. Either
* way, start up the XLOG machinery, and register to have it closed
* down at exit.
*
* We don't yet have an aux-process resource owner, but StartupXLOG
* and ShutdownXLOG will need one. Hence, create said resource owner
* (and register a callback to clean it up after ShutdownXLOG runs).