You have observed some SQL error codes (in the format of
sql_error_code = XXXXX) emitted in the logs of Heroku Postgres, and are not sure what they mean.
Postgres emits error codes for all operations, including successful operations, that follow the
SQLSTATE conventions as part of the SQL standard.
The most common emitted error code is
00000, meaning "successful completion". This is equivalent to an
INFO log level. Detailed information on all the error codes can be found here: https://www.postgresql.org/docs/current/static/errcodes-appendix.html