Обсуждение: min_wal_size > max_wal_size is accepted
Hello, It is possible to startup an instance with min > max, without the system complaining: mrechte=# show min_wal_size ; 2020-05-07 11:12:11.422 CEST [11098] LOG: durée : 0.279 ms min_wal_size -------------- 128MB (1 ligne) mrechte=# show max_wal_size ; 2020-05-07 11:12:12.814 CEST [11098] LOG: durée : 0.275 ms max_wal_size -------------- 64MB (1 ligne) This could be an issue ?
Hi,
Le jeu. 7 mai 2020 à 11:13, Marc Rechté <marc4@rechte.fr> a écrit :
Hello,
It is possible to startup an instance with min > max, without the system
complaining:
mrechte=# show min_wal_size ;
2020-05-07 11:12:11.422 CEST [11098] LOG: durée : 0.279 ms
min_wal_size
--------------
128MB
(1 ligne)
mrechte=# show max_wal_size ;
2020-05-07 11:12:12.814 CEST [11098] LOG: durée : 0.275 ms
max_wal_size
--------------
64MB
(1 ligne)
This could be an issue ?
I don't see how this could be an issue. You'll get a checkpoint every time 64MB have been written before checkpoint_timeout kicked in. And WAL files will be removed if you have more than 128MB of them.
Not the smartest configuration, but not a damaging one either.
--
Guillaume.
> Hi, > > Le jeu. 7 mai 2020 à 11:13, Marc Rechté <marc4@rechte.fr > <mailto:marc4@rechte.fr>> a écrit : > > Hello, > > It is possible to startup an instance with min > max, without the > system > complaining: > > mrechte=# show min_wal_size ; > > 2020-05-07 11:12:11.422 CEST [11098] LOG: durée : 0.279 ms > > min_wal_size > > -------------- > > 128MB > > (1 ligne) > > > > mrechte=# show max_wal_size ; > > 2020-05-07 11:12:12.814 CEST [11098] LOG: durée : 0.275 ms > > max_wal_size > > -------------- > > 64MB > > (1 ligne) > > > This could be an issue ? > > > I don't see how this could be an issue. You'll get a checkpoint every > time 64MB have been written before checkpoint_timeout kicked in. And WAL > files will be removed if you have more than 128MB of them. > > Not the smartest configuration, but not a damaging one either. > > > -- > Guillaume. I have some doubts when I see such code in backend/access/transam/xlog.c:2334 if (recycleSegNo < minSegNo) recycleSegNo = minSegNo; if (recycleSegNo > maxSegNo) recycleSegNo = maxSegNo;