[PATCH] Filter error log statements by sqlstate

Allow the default log_min_error_statement to be overridden per sqlstate
to make it possible to filter out some error types while maintaining a
low log_min_error_statement or enable logging for some error types when
the default is to not log anything.

I've tried to do something like this using rsyslog filters, but that's
pretty awkward and doesn't work at all when the statement is split to
multiple syslog messages.

https://github.com/saaros/postgres/compare/log-by-sqlstate

  src/backend/utils/error/elog.c | 183
++++++++++++++++++++++++++++++++++++++++-
  src/backend/utils/misc/guc.c   |  14 +++-
  src/include/utils/guc.h        |   4 +
  src/include/utils/guc_tables.h |   1 +
  4 files changed, 199 insertions(+), 3 deletions(-)

/ Oskari