[Pgpool-general] Proposal: Increase log about data mismatch

[Pablo Milano]

When pgpool detects a data mismatch between backends, it stops replication
and logs only "kind does not match between master and slave". It would be
good to know WICH was the mismatch, in order to debug. The log should say
something like:

"Data mismatch between master and slave in sentence: [SQL SENTENCE]"

And optionally, show the data mismatch itself. As data mismatchs should not
be something usual, it would be good to know some more detail when it
happens.

The motivation of this is our production environment, wich uses pgpool with
databases "exactly" replicated using tar, but it usually stops replication
because of "data mismatchs". We do not enable Sentence logging in postgres
because it consumes huge amounts of disk and degrades performance.

Thanks in advance