Re: Global snapshots

>> would like to know if the patch related to CSN based snapshot [2] is a
>> precursor for this, if not, then is it any way related to this patch
>> because I see the latest reply on that thread [2] which says it is an
>> infrastructure of sharding feature but I don't understand completely
>> whether these patches are related?
>I need some time to study this patch. At first sight it is different.

This patch[2] is almost base on [3], because I think [1] is talking about 2PC
and FDW, so this patch focus on CSN only and I detach the global snapshot
part and FDW part from the [1] patch.

I notice CSN will not survival after a restart in [1] patch, I think it may not the
right way, may be it is what in last mail "Needs guarantees of monotonically
increasing of the CSN in the case of an instance restart/crash etc" so I try to
add wal support for CSN on this patch.

That's why this thread exist.

> [1] - https://www.postgresql.org/message-id/CA%2Bfd4k4v%2BKdofMyN%2BjnOia8-7rto8tsh9Zs3dd7kncvHp12WYw%40mail.gmail.com
> [2] - https://www.postgresql.org/message-id/2020061911294657960322%40highgo.ca
[3]https://www.postgresql.org/message-id/21BC916B-80A1-43BF-8650-3363CCDAE09C%40postgrespro.ru

Regards,
Highgo Software (Canada/China/Pakistan)
URL : www.highgo.ca
EMAIL: mailto:movead(dot)li(at)highgo(dot)ca