On 2011-03-04 22:18, Jaime Casanova wrote:
On Thu, Mar 3, 2011 at 1:23 PM, Robert Haas<robertmh...@gmail.com>  wrote:
The patch sets "*" as the default, so all standbys are synchronous by
default.

Would you prefer it if it was blank, meaning no standbys are
synchronous, by default?
I think * is a reasonable default.

Actually i would prefer to have standbys asynchronous by default...
though is true that there will be no waits until i set
synchronous_replication to on... 1) it could be confusing to see a
SYNC standby in pg_stat_replication by default when i wanted all of
them to be async,
I see no problem with * for synchronous_standby names, such that *if* synchronous_replication = on, then all standbys are sync. Also for the beginning experimenter with sync rep: what would you expect after only turning 'synchronous_replication' = on? ISTM better than : you need to change two parameters from their default to get a replica in sync mode.
  2) also * will give priority 1 to all standbys so it
doesn't seem like a very useful out-of-the-box configuration, better
to make the dba to write the standby names in the order they want

As somebody with a usecase for two hardware-wise equal sync replicas for the same master (and a single async replica), the whole ordering of sync standbys is too much feature anyway, since it will cause unneccesary 'which is the sync replica' switching. Besides that, letting all syncs have the same priority sounds like the only thing the server can do, if the dba has not specified it explicitly. I would see it as improvement if order in standby_names doesn't mean priority, and that priority could be specified with another parameter (and default: all sync priorities the same)

regards,
Yeb Havinga








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