Re: max_wal_size

On Tue, Jun 2, 2020 at 11:42:01PM +0300, Pavel Luzanov wrote: > Hello, > > On 02.06.2020 22:35, Bruce Momjian wrote: > > On Thu, May 28, 2020 at 12:21:14PM +0300, p.luza...@postgrespro.ru wrote: > > > WAL |---|-+-|-+-|-+-> > > > > > > a

Re: max_wal_size

Hello, On 02.06.2020 22:35, Bruce Momjian wrote: On Thu, May 28, 2020 at 12:21:14PM +0300, p.luza...@postgrespro.ru wrote: WAL |---|-+-|-+-|-+-> a b c CP +-+ +-+ +-+ b

Re: max_wal_size

On Thu, May 28, 2020 at 12:21:14PM +0300, p.luza...@postgrespro.ru wrote: > WAL |---|-+-|-+-|-+-> > >a b c > CP +-+ +-+ +-+ > b e b e b e > > Checkpointer

Re: max_wal_size

David, I don't know whether a change along those lines to the configuration reference page is useful or not - I wouldn't make one without a comprehensive re-read of the actual background/learning section of the documentation. My gut instinct is that I just don't think the documentation can do t

Re: max_wal_size

On Thu, May 28, 2020 at 2:21 AM wrote: > > Now we have the glossary. According to the glossary, a checkpoint has two > meanings. > > The first meaning is that this is a point: > "A point in the WAL sequence at which it is guaranteed that the heap and > index data files have been updated with all

Re: max_wal_size

David, I think part of the issue is your operating with a mental model of this contrary to the one the documentation was written for. I made this assumption(checkpoints triggered by size, checkpoint_completion_target=1) only for simplifying example. (Although there is a practical task: calcula

Re: max_wal_size

On Wed, May 27, 2020, 14:12 wrote: > David, > > > For 0.5 you get 2/3rds consumption: ( n / ( 1 + 0.5 ) ) = n * 2/3 > > Exactly, for checkpoint_completion_target=0.5 the distance between > checkpoints is 2/3 of max_wal_size. > > But back to the documentation of max_wal_size. > "Maximum size to l

Re: max_wal_size

David, For 0.5 you get 2/3rds consumption: ( n / ( 1 + 0.5 ) ) = n * 2/3 Exactly, for checkpoint_completion_target=0.5 the distance between checkpoints is 2/3 of max_wal_size. But back to the documentation of max_wal_size. "Maximum size to let the WAL grow to between automatic WAL checkpoi

Re: max_wal_size

On Wed, May 27, 2020 at 9:17 AM wrote: > David, > > > This setting is the indirect means to ensure that the WAL directory > > doesn't get too large by forcing a checkpoint thus allowing the > > corresponding WAL to be removed. > > > This is a soft limit, ok. > But the question is a little differe

Re: max_wal_size

David, This setting is the indirect means to ensure that the WAL directory doesn't get too large by forcing a checkpoint thus allowing the corresponding WAL to be removed. This is a soft limit, ok. But the question is a little different. Suppose we have: version >= 11, no replication slots,

Re: max_wal_size

On Wed, May 27, 2020 at 8:18 AM PG Doc comments form wrote: > The following documentation comment has been logged on the website: > > Page: https://www.postgresql.org/docs/12/runtime-config-wal.html > Description: > > About parameter max_wal_size the documentation says that "Maximum size to > let

Re: max_wal_size

On 27.05.2020 13:16, Andreas Kretschmer wrote: Am 27.05.20 um 12:11 schrieb Pavel Luzanov: Hello, About parameter max_wal_size the documentation says: "Maximum size to let the WAL grow to between automatic WAL

Re: max_wal_size

Andreas, size between checkpoints, size of all wal's can be higher, see wal_keep_segments. Hm, I also thought, but after looking at the source , it seems like this is a restriction on all files i

Re: max_wal_size

Am 27.05.20 um 12:11 schrieb Pavel Luzanov: Hello, About parameter max_wal_size the documentation says: "Maximum size to let the WAL grow to between automatic WAL checkpoints." Is it correct? The size betw