OperationalError: canceling statement due to conflict with recovery

[ukanga]

Has been observed in different places, most likely during read operations with a read replica db

Exception in request: OperationalError: canceling statement due to conflict with recovery
DETAIL:  User query might have needed to see row versions that must be removed.
Traceback (most recent call last):
  File "/..../app-versioned/1486626094/onadata/apps/viewer/tasks.py", line 293, in create_sav_zip_export
    options
  File "/..../app-versioned/1486626094/onadata/libs/utils/export_tools.py", line 156, in generate_export
    options=options, columns_with_hxl=columns_with_hxl
  File "/..../app-versioned/1486626094/onadata/libs/utils/export_builder.py", line 861, in to_zipped_sav
    for d in data:
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/models/query.py", line 258, in __iter__
    self._fetch_all()
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/models/query.py", line 1074, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/models/query.py", line 158, in __iter__
    for row in compiler.results_iter():
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 802, in results_iter
    results = self.execute_sql(MULTI)
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 848, in execute_sql
    cursor.execute(sql, params)
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/utils.py", line 95, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/..../.virtualenvs/onadata/local/lib/python2.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
OperationalError: canceling statement due to conflict with recovery
DETAIL:  User query might have needed to see row versions that must be removed.

Aha! Link: https://ona.aha.io/features/PROD-631