> Communication takes time – network latencies. What if during this
> communication, the situation becomes different?
We have to accept it (and do the best to mitigate any consequence of
the problem). I think there's no such a system which presuppose 0
communication latency.
> What if some of them cannot communicate with each other due to network issues?
Can you elaborate more? There are many scenarios for communication
break down. I hesitate to discuss all of them on this forum since this
is for discussions on PostgreSQL, not Pgpool-II. I am welcome you to
join and continue the discussion on pgpool mailing list.
> What if pg1 is currently primary, pg0 is standby, both are healthy, but
> due not network issues, both pg1 and w2 are not reachable to other
> nodes? Will pg1 remain primary, and w0 and w1 decide to promote pg0?
pg1 will remain primary but it is set to "quarantine" state from
pgpool's point of view, which means clients cannot access pg1 via
pgpool.
w0 and w1 will decide to promote pg0.
Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp