rolled back transactions logging

Hi all,
I can see that value pg_stat_database.xact_rollback for my db is instantly
growing, but I can not find a way to log these rolled back transactions
(or, may be, last statement within).
Even with

log_min_duration_statement = 0

log_statement = 'all'

there is no error messages in log.

I mean that I was expecting something like this (for example)

ERROR: value too long for type character varying(4096)
> ERROR: current transaction is aborted, commands ignored until end of
> transaction block

or to see ROLLBACK statement directly.

Can VACUUM be a reason of xact_rollback increasing?

Server version is 9.2.4

P.S,
Root problem is the number of wal files, it raised up significantly (more
than 4 times) with the same workload and I do not know why.

--
Regards, Andrey Lizenko