Hi,
On Wed, Jul 17, 2024 at 12:52:12PM +0900, Michael Paquier wrote:
> On Tue, Jul 16, 2024 at 10:37:39AM +0900, Michael Paquier wrote:
> > On Fri, Jul 12, 2024 at 01:01:19PM +0000, Bertrand Drouvot wrote:
> >> Instead of removing the stat file, should we keep it around until the
> >> first call
> >> to pgstat_write_statsfile()?
> >
> > Oops. You are right, I have somewhat missed the unlink() once we are
> > done reading the stats file with a correct redo location.
>
> The durable_rename() part has been applied. Please find attached a
> rebase of the patch set with all the other comments addressed.
Thanks!
Looking at 0001:
1 ===
- pgstat_write_statsfile();
+ pgstat_write_statsfile(GetRedoRecPtr());
Not related with your patch but this comment in the GetRedoRecPtr() function:
* grabbed a WAL insertion lock to read the authoritative value in
* Insert->RedoRecPtr
sounds weird. Should'nt that be s/Insert/XLogCtl/?
2 ===
+ /* Write the redo LSN, used to cross check the file loaded */
Nit: s/loaded/read/?
3 ===
+ /*
+ * Read the redo LSN stored in the file.
+ */
+ if (!read_chunk_s(fpin, &file_redo) ||
+ file_redo != redo)
+ goto error;
I wonder if it would make sense to have dedicated error messages for
"file_redo != redo" and for "format_id != PGSTAT_FILE_FORMAT_ID". That would
ease to diagnose as to why the stat file is discarded.
Looking at 0002:
LGTM
Looking at 0003:
4 ===
@@ -5638,10 +5634,7 @@ StartupXLOG(void)
* TODO: With a bit of extra work we could just start with a pgstat file
* associated with the checkpoint redo location we're starting from.
*/
- if (didCrash)
- pgstat_discard_stats();
- else
- pgstat_restore_stats(checkPoint.redo);
+ pgstat_restore_stats(checkPoint.redo)
remove the TODO comment?
5 ===
+ * process) if the stats file has a redo LSN that matches with the .
unfinished sentence?
6 ===
- * Should only be called by the startup process or in single user mode.
+ * This is called by the checkpointer or in single-user mode.
*/
void
-pgstat_discard_stats(void)
+pgstat_flush_stats(XLogRecPtr redo)
{
Would that make sense to add an Assert in pgstat_flush_stats()? (checking what
the above comment states).
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
