#25312: Bug: AutoField backed by Postgres 9+ creates error condition
------------------------------+--------------------------------------------
     Reporter:  infintesimal  |      Owner:  nobody
         Type:  Bug           |     Status:  new
    Component:                |    Version:  1.7
  Uncategorized               |
     Severity:  Normal        |   Keywords:  AutoField, Postgres, Sequences
 Triage Stage:  Unreviewed    |  Has patch:  0
Easy pickings:  0             |      UI/UX:  0
------------------------------+--------------------------------------------
 The essence of this bug report is that models.py creates an inherent
 conflict between default, autoincrementing id fields (AutoField) and what
 a postgres 9.x (9.4 in my case) assigns as the type for the auto
 incrementing field. When makemigration creates the sequence, the sequence
 is created as a big integer. However, the database table that uses the
 sequence (the id field) is created as an integer. So once the value of the
 sequence exceeds the maximum value of a 32 bit integer, the insert will
 fail.

 Below is models.py code and some psql command line foo to illustrate the
 problem

 {{{
 import datetime
 import hashlib
 import os
 from math import sqrt
 from random import Random
 from django.db import models
 from django.db.models.query import Q
 from django.utils.text import slugify
 from djangoratings.fields import RatingField
 from django_pgjson.fields import JsonBField
 from django_images.models import Image as BaseImage
 from django.utils import timezone

 class EventName(models.Model):
   event_name = models.CharField(max_length=500, blank=False, null=False)
   event_desc = models.CharField(max_length=500, blank=False, null=True)
   event_creation_date = models.DateTimeField(auto_now_add=True,null=False)
   event_update_date = models.DateTimeField(auto_now=True,null=False)

   def __unicode__(self):
     return self.name

 }}}

 {{{
 steves_app=> \d eventlogs_eventname_id_seq
      Sequence "public.eventlogs_eventname_id_seq"
     Column     |  Type   |           Value
 ---------------+---------+----------------------------
  sequence_name | name    | eventlogs_eventname_id_seq
  last_value    | bigint  | 1
  start_value   | bigint  | 1
  increment_by  | bigint  | 1
  max_value     | bigint  | 9223372036854775807
  min_value     | bigint  | 1
  cache_value   | bigint  | 1
  log_cnt       | bigint  | 0
  is_cycled     | boolean | f
  is_called     | boolean | f
 Owned by: public.eventlogs_eventname.id

 steves_app=> \d eventlogs_eventname
                                         Table "public.eventlogs_eventname"
        Column        |           Type           |
 Modifiers
 
---------------------+--------------------------+------------------------------------------------------------------
  id                  | integer                  | not null default
 nextval('eventlogs_eventname_id_seq'::regclass)
  event_name          | character varying(500)   | not null
  event_desc          | character varying(500)   |
  event_creation_date | timestamp with time zone | not null
  event_update_date   | timestamp with time zone | not null
 Indexes:
     "eventlogs_eventname_pkey" PRIMARY KEY, btree (id)
 Referenced by:
     TABLE "eventlogs_event" CONSTRAINT
 "eventlog_event_id_id_153f5722b6e1dffb_fk_eventlogs_eventname_id" FOREIGN
 KEY (event_id_id) REFERENCES eventlogs_eventname(id) DEFERRABLE INITIALLY
 DEFERRED

 fitcode_app=> alter sequence eventlogs_eventname_id_seq restart with
 4294967297;
 ALTER SEQUENCE
 fitcode_app=> insert into
 
eventlogs_eventname(event_name,event_desc,event_creation_date,event_update_date)
 values ('foo','bar',now(),now());
 ERROR:  integer out of range

 }}}

--
Ticket URL: <https://code.djangoproject.com/ticket/25312>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.

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