get statistics do not work with postgresql database

[Vadim Rovachev]

Steps to reproduce:
1. Install devstack with postgresql database
2. Configure ceilometer to using postgresql
3. Get meter list(200 OK)
4. Get statistics for any meters(By example: vcpus).
   Expected result: 200 OK
   Actual result:
Status: 500
Body:
{"error_message": {"debuginfo": null, "faultcode": "Server", "faultstring": "(ProgrammingError) column \"meter.counter_unit\" must appear in the GROUP BY clause or be used in an aggregate function\nLINE 1: SELECT meter.counter_unit AS unit, min(meter.timestamp) AS t...\n ^\n 'SELECT meter.counter_unit AS unit, min(meter.timestamp) AS tsmin, max(meter.timestamp) AS tsmax, avg(meter.counter_volume) AS avg, sum(meter.counter_volume) AS sum, min(meter.counter_volume) AS min, max(meter.counter_volume) AS max, count(meter.counter_volume) AS count \\nFROM meter \\nWHERE meter.counter_name = %(counter_name_1)s' {'counter_name_1': 'vcpus'}"}}

=====================================================
Stacktrace(in ceilometer-api log):
=====================================================
2013-11-28 12:42:22.639 23577 ERROR wsme.api [-] Server-side error: "(ProgrammingError) column "meter.counter_unit" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: SELECT meter.counter_unit AS unit, min(meter.timestamp) AS t...
               ^
 'SELECT meter.counter_unit AS unit, min(meter.timestamp) AS tsmin, max(meter.timestamp) AS tsmax, avg(meter.counter_volume) AS avg, sum(meter.counter_volume) AS sum, min(meter.counter_volume) AS min, max(meter.counter_volume) AS max, count(meter.counter_volume) AS count \nFROM meter \nWHERE meter.counter_name = %(counter_name_1)s' {'counter_name_1': 'vcpus'}". Detail:
Traceback (most recent call last):

  File "/usr/local/lib/python2.7/dist-packages/wsmeext/pecan.py", line 77, in callfunction
    result = f(self, *args, **kwargs)

  File "/opt/stack/new/ceilometer/ceilometer/api/controllers/v2.py", line 816, in statistics
    for c in computed]

  File "/opt/stack/new/ceilometer/ceilometer/storage/impl_sqlalchemy.py", line 611, in get_meter_statistics
    for res in self._make_stats_query(sample_filter, groupby):

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2227, in __iter__
    return self._execute_and_instances(context)

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2242, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1449, in execute
    params)

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1584, in _execute_clauseelement
    compiled_sql, distilled_params

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1698, in _execute_context
    context)

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1691, in _execute_context
    context)

  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 331, in do_execute
    cursor.execute(statement, parameters)

ProgrammingError: (ProgrammingError) column "meter.counter_unit" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: SELECT meter.counter_unit AS unit, min(meter.timestamp) AS t...
               ^
 'SELECT meter.counter_unit AS unit, min(meter.timestamp) AS tsmin, max(meter.timestamp) AS tsmax, avg(meter.counter_volume) AS avg, sum(meter.counter_volume) AS sum, min(meter.counter_volume) AS min, max(meter.counter_volume) AS max, count(meter.counter_volume) AS count \nFROM meter \nWHERE meter.counter_name = %(counter_name_1)s' {'counter_name_1': 'vcpus'}

localhost - - [28/Nov/2013 12:42:22] "GET /v2/meters/vcpus/statistics HTTP/1.1" 500 136

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/59204

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/59214

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/86399

[Openstack Gerrit (openstack-gerrit)]

Reviewed: https://review.openstack.org/86399
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=551bbbb0dff43d22d7cca7826af1b3ef5868168b
Submitter: Jenkins
Branch: master

commit 551bbbb0dff43d22d7cca7826af1b3ef5868168b
Author: Gordon Chung <email address hidden>
Date: Wed Apr 9 13:01:50 2014 -0400

    fix statistics query in postgres

    when aggregate functions present, postgres requires all
    non-aggregate columns selected to be included in group by clause
    to ensure a single value is selected.

    Change-Id: Iccbcd8046cca872e8eba472f48fa392114f34426
    Closes-Bug: #1256318

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/114275

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/114275
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=0ba75c8711341ddd4beac19b287c3c1f6ac0f3e0
Submitter: Jenkins
Branch: stable/icehouse

commit 0ba75c8711341ddd4beac19b287c3c1f6ac0f3e0
Author: Gordon Chung <email address hidden>
Date: Wed Apr 9 13:01:50 2014 -0400

    fix statistics query in postgres

    when aggregate functions present, postgres requires all
    non-aggregate columns selected to be included in group by clause
    to ensure a single value is selected.

    Change-Id: Iccbcd8046cca872e8eba472f48fa392114f34426
    Closes-Bug: #1256318
    (cherry picked from commit 551bbbb0dff43d22d7cca7826af1b3ef5868168b)