Re: wire protocol errors on Debian (py3/psyco 2.8) - Mailing list psycopg

On 3/14/20 9:12 AM, Karsten Hilbert wrote:
> Dear Adrian,
> 
> unfortunately, we don't have direct contact with the reporter
> (only via our mailing list and they haven't answered so far).
> 
>> How was psycopg2 installed?
> 
> Given they are running a "standard" Debian/Unstable with a
> Debian package of GNUmed installed and the matching psycopg2
> package version
> 
>     psycopg2 module version: 2.8.4 (dt dec pq3 ext lo64)
> 
> I suspect they apt-get install'ed it. Which assumption seems
> supported by the package file string in:
> 
>     PostgreSQL via DB-API module "<module 'psycopg2' from '/usr/lib/python3/dist-packages/psycopg2/__init__.py'>":
APIlevel 2.0, thread safety 2, parameter style "pyformat"
 
> 
> The one thing that's odd is that the Python version
> 
>     Python 3.7.6 (default, Jan 19 2020, 22:34:52) <\n>[GCC 9.2.1 20200117] on linux (posix)
> 
> does not match what's available from Debian:
> 
>     python3:
>       Installiert:           3.7.3-1
>       Installationskandidat: 3.7.3-1
>       Versionstabelle:
>          3.8.2-1 500
>             500 https://deb.debian.org/debian unstable/main i386 Packages
>          3.7.5-3 500
>             500 https://deb.debian.org/debian bullseye/main i386 Packages
>      *** 3.7.3-1 990
>             990 https://deb.debian.org/debian buster/main i386 Packages
>             100 /var/lib/dpkg/status

To me resolving the above would help with the below.


I have to go out shortly and will not be able to look over the below in 
detail until later.

> 
>> What is the code being run when the errors are thrown?
> 
> It happens (two reports so far) at different stages during
> the bringup phase of the GNUmed client. The code being run is
> the same, but the time of occurrence is different.
> 
> case 1:
> 
>     select vco.value from cfg.v_cfg_opts_numeric vco where vco.owner = CURRENT_USER and vco.workplace = %(wp)s and
vco.option= %(opt)s and vco.cookie is null limit 1
 
> 
> case 2:
> 
>     select _(message) from cfg.db_logon_banner
> 
> where _() translates "message". This is the Python code being
> run (the place of error marked with xxxxx):
> 
> def run_ro_queries(link_obj=None, queries=None, verbose=False, return_data=True, get_col_idx=False):
>     """Run read-only queries.
> 
>     <queries> must be a list of dicts:
>         [
>             {'cmd': <string>, 'args': <dict> or <tuple>},
>             {...},
>             ...
>         ]
>     """
>     if isinstance(link_obj, dbapi._psycopg.cursor):
>         curs = link_obj
>         curs_close = lambda *x:None
>         tx_rollback = lambda *x:None
>         readonly_rollback_just_in_case = lambda *x:None
>     elif isinstance(link_obj, dbapi._psycopg.connection):
>         curs = link_obj.cursor()
>         curs_close = curs.close
>         tx_rollback = link_obj.rollback
>         if link_obj.autocommit is True:        # readonly connection ?
>             readonly_rollback_just_in_case = link_obj.rollback
>         else:
>             # do not rollback readonly queries on passed-in readwrite
>             # connections just in case because they may have already
>             # seen fully legitimate write action which would get lost
>             readonly_rollback_just_in_case = lambda *x:None
>     elif link_obj is None:
>         conn = get_connection(readonly = True, verbose = verbose)
>         curs = conn.cursor()
>         curs_close = curs.close
>         tx_rollback = conn.rollback
>         readonly_rollback_just_in_case = conn.rollback
>     else:
>         raise ValueError('link_obj must be cursor, connection or None but not [%s]' % link_obj)
> 
>     if verbose:
>         _log.debug('cursor: %s', curs)
> 
>     for query in queries:
>         try:
>             args = query['args']
>         except KeyError:
>             args = None
>         try:
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>             curs.execute(query['cmd'], args)
> xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>             if verbose:
>                 gmConnectionPool.log_cursor_state(curs)
>         except PG_ERROR_EXCEPTION as pg_exc:
>             _log.error('query failed in RO connection')
>             gmConnectionPool.log_pg_exception_details(pg_exc)
>             try:
>                 curs_close()
>             except PG_ERROR_EXCEPTION as pg_exc2:
>                 _log.exception('cannot close cursor')
>                 gmConnectionPool.log_pg_exception_details(pg_exc2)
>             try:
>                 tx_rollback()        # need to rollback so ABORT state isn't preserved in pooled conns
>             except PG_ERROR_EXCEPTION as pg_exc2:
>                 _log.exception('cannot rollback transaction')
>                 gmConnectionPool.log_pg_exception_details(pg_exc2)
>             if pg_exc.pgcode == sql_error_codes.INSUFFICIENT_PRIVILEGE:
>                 details = 'Query: [%s]' % curs.query.strip().strip('\n').strip().strip('\n')
>                 if curs.statusmessage != '':
>                     details = 'Status: %s\n%s' % (
>                         curs.statusmessage.strip().strip('\n').strip().strip('\n'),
>                         details
>                     )
>                 if pg_exc.pgerror is None:
>                     msg = '[%s]' % pg_exc.pgcode
>                 else:
>                     msg = '[%s]: %s' % (pg_exc.pgcode, pg_exc.pgerror)
>                 raise gmExceptions.AccessDenied (
>                     msg,
>                     source = 'PostgreSQL',
>                     code = pg_exc.pgcode,
>                     details = details
>                 )
>             raise
>         except Exception:
>             _log.exception('error during query run in RO connection')
>             gmConnectionPool.log_cursor_state(curs)
>             try:
>                 curs_close()
>             except PG_ERROR_EXCEPTION as pg_exc:
>                 _log.exception('cannot close cursor')
>                 gmConnectionPool.log_pg_exception_details(pg_exc)
>             try:
>                 tx_rollback()        # need to rollback so ABORT state isn't preserved in pooled conns
>             except PG_ERROR_EXCEPTION as pg_exc:
>                 _log.exception('cannot rollback transation')
>                 gmConnectionPool.log_pg_exception_details(pg_exc)
>             raise
> 
>     data = None
>     col_idx = None
>     if return_data:
>         data = curs.fetchall()
>         if verbose:
>             _log.debug('last query returned [%s (%s)] rows', curs.rowcount, len(data))
>             _log.debug('cursor description: %s', curs.description)
>         if get_col_idx:
>             col_idx = get_col_indices(curs)
> 
>     curs_close()
>     # so we can see data committed meanwhile if the
>     # link object had been passed in and thusly might
>     # be part of a long-running read-only transaction
>     readonly_rollback_just_in_case()
>     return (data, col_idx)
> 
> 
> Thanks,
> Karsten
> --
> GPG  40BE 5B0E C98E 1713 AFA6  5BC0 3BEA AC80 7D4F C89B
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com