Fujii Masao wrote:
How should the synchronous replication behave when the number of connected
standby servers is less than quorum?
1. Ignore quorum. The current patch adopts this. If the ACKs from all
connected standbys have arrived, transaction commit is successful
even if the number of standbys is less than quorum. If there is no
connected standby, transaction commit always is successful without
regard to quorum.
2. Observe quorum. Aidan wants this. Until the number of connected
standbys has become more than or equal to quorum, transaction commit
waits.
Which is the right behavior of quorum commit? Or we should add new
parameter specifying the behavior of quorum commit?
Initially I also expected the quorum to behave like described by
Aidan/option 2. Also, IMHO the name "quorom" is a bit short, like having
"maximum" but not saying a max_something.
quorum_min_sync_standbys
quorum_max_sync_standbys
The question remains what are the sync standbys? Does it mean not-async?
Intuitively by looking at the enumeration of replication_mode I'd think
that the sync standbys are all standby's that operate in a not async
mode. That would be clearer with a boolean sync (or not) and for sync
standbys the replication_mode specified.
regards,
Yeb Havinga
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