Re: use CREATE DATABASE STRATEGY = FILE_COPY in pg_upgrade
От | Nathan Bossart |
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Тема | Re: use CREATE DATABASE STRATEGY = FILE_COPY in pg_upgrade |
Дата | |
Msg-id | ZmCbbi8v8J1H1HfK@nathan обсуждение исходный текст |
Ответ на | Re: use CREATE DATABASE STRATEGY = FILE_COPY in pg_upgrade (Ranier Vilela <ranier.vf@gmail.com>) |
Список | pgsql-hackers |
On Wed, Jun 05, 2024 at 01:47:09PM -0300, Ranier Vilela wrote: > Why not use it too, if not binary_upgrade? > > else > { > appendPQExpBuffer(creaQry, "CREATE DATABASE %s WITH TEMPLATE = template0 > STRATEGY = FILE_COPY", > qdatname); > } > > It seems to me that it also improves in any use. Well, if that is true, and I'm not sure it is, then we should probably consider changing the default STRATEGY in the server instead. I haven't looked too deeply, but my assumption is that when fsync is disabled (as it is when restoring schemas during pg_upgrade), both checkpointing and copying the template database are sufficiently fast enough to beat writing out all the data to WAL. Furthermore, in my test, all the databases were basically empty, so I suspect that some CREATE DATABASE commands could piggy-back on checkpoints initiated by others. This might not be the case when there are many objects in each database, and that is a scenario I have yet to test. -- nathan
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