Re: Snapshot synchronization, again...

On Dec30, 2010, at 13:31 , Joachim Wieland wrote:
> We return snapshot information as a chunk of data to the client. At
> the same time however, we set a checksum in shared memory to protect
> against modification of the snapshot. A publishing backend can revoke
> its snapshot by deleting the checksum and a backend that is asked to
> install a snapshot can verify that the snapshot is correct and current
> by calculating the checksum and comparing it with the one in shared
> memory.

We'd still have to stream these checksums to the standbys though,
or would they be exempt from the checksum checks?

I still wonder whether these checks are worth the complexity. I
believe we'd only allow snapshot modifications for read-only queries
anyway, so what point is there in preventing clients from setting
broken snapshots?

best regards,
Florian Pflug