[Django] #25470: Django cast DATE field to DATETIME unexpectedly
Django
----------------------------------------------+--------------------
Reporter: stanleyxu2005 | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Database layer (models, ORM) | Version: 1.8
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------------------------+--------------------
I posted a question at http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = set(Model1.objects.dates("date", kind="day"))
}}}
I dumped the django queries.
{{{
[{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`model1_table`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `model1_table` WHERE `model1_table`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
]
}}}
Actually the second query did a type cast. This is the root cause of the
slow.
I'd like to know, why django cast DATE to DATETIME. Is it a bug?
--
Ticket URL: <https://code.djangoproject.com/ticket/25470>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by stanleyxu2005):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Old description:
> I posted a question at http://stackoverflow.com/questions/32795047/have-a
> -perforamance-issue-of-query-date-object-using-django-queryset
>
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = set(Model1.objects.dates("date", kind="day"))
> }}}
>
> I dumped the django queries.
>
> {{{
> [{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`model1_table`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `model1_table` WHERE `model1_table`.`date` IS NOT
> NULL ORDER BY `datefield` ASC"}
> ]
> }}}
>
> Actually the second query did a type cast. This is the root cause of the
> slow.
>
> I'd like to know, why django cast DATE to DATETIME. Is it a bug?
New description:
I posted a question at http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = set(Model1.objects.dates("date", kind="day"))
}}}
I dumped the django queries.
{{{
[{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`model1_table`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `model1_table` WHERE `model1_table`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
]
}}}
I noticed that the second query did a type cast. The cast is not a
necessary step. It slows down when the amount of records is huge. I pretty
sure this is the root cause of the slow.
The table is created by django. The field is exactly `DATE` field. I'd
like to know, why django cast DATE to DATETIME. Is it a bug?
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:1>
Django
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Description changed by stanleyxu2005:
Old description:
> I posted a question at http://stackoverflow.com/questions/32795047/have-a
> -perforamance-issue-of-query-date-object-using-django-queryset
>
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = set(Model1.objects.dates("date", kind="day"))
> }}}
>
> I dumped the django queries.
>
> {{{
> [{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`model1_table`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `model1_table` WHERE `model1_table`.`date` IS NOT
> NULL ORDER BY `datefield` ASC"}
> ]
> }}}
>
> I noticed that the second query did a type cast. The cast is not a
> necessary step. It slows down when the amount of records is huge. I
> pretty sure this is the root cause of the slow.
>
> The table is created by django. The field is exactly `DATE` field. I'd
> like to know, why django cast DATE to DATETIME. Is it a bug?
New description:
I posted a question at http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = set(Model1.objects.dates("date", kind="day"))
}}}
I dumped the django queries.
{{{
[{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
]
}}}
I noticed that the second query did a type cast. The cast is not a
necessary step. It slows down when the amount of records is huge. I pretty
sure this is the root cause of the slow.
The table is created by django. The field is exactly `DATE` field. I'd
like to know, why django cast DATE to DATETIME. Is it a bug?
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:2>
Django
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Description changed by stanleyxu2005:
Old description:
> I posted a question at http://stackoverflow.com/questions/32795047/have-a
> -perforamance-issue-of-query-date-object-using-django-queryset
>
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = set(Model1.objects.dates("date", kind="day"))
> }}}
>
> I dumped the django queries.
>
> {{{
> [{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
> ORDER BY `datefield` ASC"}
> ]
> }}}
>
> I noticed that the second query did a type cast. The cast is not a
> necessary step. It slows down when the amount of records is huge. I
> pretty sure this is the root cause of the slow.
>
> The table is created by django. The field is exactly `DATE` field. I'd
> like to know, why django cast DATE to DATETIME. Is it a bug?
New description:
I posted a question at http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = Model1.objects.dates("date", kind="day")
}}}
I dumped the django queries.
{{{
[{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
]
}}}
I noticed that the second query did a type cast. The cast is not a
necessary step. It slows down when the amount of records is huge. I pretty
sure this is the root cause of the slow.
The table is created by django. The field is exactly `DATE` field. I'd
like to know, why django cast DATE to DATETIME. Is it a bug?
Currently, I use a workaround:
{{{
db_dates = [dt['date'] for dt in
Model1.objects.order_by('date').values('date').distinct()]
}}}
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:3>
Django
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Description changed by stanleyxu2005:
Old description:
> I posted a question at http://stackoverflow.com/questions/32795047/have-a
> -perforamance-issue-of-query-date-object-using-django-queryset
>
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = Model1.objects.dates("date", kind="day")
> }}}
>
> I dumped the django queries.
>
> {{{
> [{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
> ORDER BY `datefield` ASC"}
> ]
> }}}
>
> I noticed that the second query did a type cast. The cast is not a
> necessary step. It slows down when the amount of records is huge. I
> pretty sure this is the root cause of the slow.
>
> The table is created by django. The field is exactly `DATE` field. I'd
> like to know, why django cast DATE to DATETIME. Is it a bug?
>
> Currently, I use a workaround:
> {{{
> db_dates = [dt['date'] for dt in
> Model1.objects.order_by('date').values('date').distinct()]
> }}}
New description:
I posted a question at http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = Model1.objects.dates("date", kind="day")
}}}
I dumped the django queries.
{{{
[{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
]
}}}
I noticed that the second query did a type cast. The cast is not a
necessary step. It slows down when the amount of records is huge. I pretty
sure this is the root cause of the slow.
The table is created by django. The field is exactly `DATE` field. I'd
like to know, why django cast DATE to DATETIME. Is it a bug?
Currently, I use a workaround:
{{{
db_dates = [dt['date'] for dt in
Model1.objects.order_by('date').values('date').distinct()]
}}}
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:4>
Django
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Description changed by stanleyxu2005:
Old description:
> I posted a question at http://stackoverflow.com/questions/32795047/have-a
> -perforamance-issue-of-query-date-object-using-django-queryset
>
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = Model1.objects.dates("date", kind="day")
> }}}
>
> I dumped the django queries.
>
> {{{
> [{u'time': u'0.000', u'sql': u'SET SQL_AUTO_IS_NULL = 0'},
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
> ORDER BY `datefield` ASC"}
> ]
> }}}
>
> I noticed that the second query did a type cast. The cast is not a
> necessary step. It slows down when the amount of records is huge. I
> pretty sure this is the root cause of the slow.
>
> The table is created by django. The field is exactly `DATE` field. I'd
> like to know, why django cast DATE to DATETIME. Is it a bug?
>
> Currently, I use a workaround:
> {{{
> db_dates = [dt['date'] for dt in
> Model1.objects.order_by('date').values('date').distinct()]
> }}}
New description:
I posted a question at http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = Model1.objects.dates("date", kind="day")
}}}
I dumped the django queries.
{{{
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
}}}
I noticed that the second query did a type cast. The cast is not a
necessary step. It slows down when the amount of records is huge. I pretty
sure this is the root cause of the slow.
The table is created by django. The field is exactly `DATE` field. I'd
like to know, why django cast DATE to DATETIME. Is it a bug?
Currently, I use a workaround:
{{{
db_dates = [dt['date'] for dt in
Model1.objects.order_by('date').values('date').distinct()]
}}}
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:5>
Django
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Description changed by stanleyxu2005:
Old description:
> I posted a question at http://stackoverflow.com/questions/32795047/have-a
> -perforamance-issue-of-query-date-object-using-django-queryset
>
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = Model1.objects.dates("date", kind="day")
> }}}
>
> I dumped the django queries.
>
> {{{
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
> ORDER BY `datefield` ASC"}
> }}}
>
> I noticed that the second query did a type cast. The cast is not a
> necessary step. It slows down when the amount of records is huge. I
> pretty sure this is the root cause of the slow.
>
> The table is created by django. The field is exactly `DATE` field. I'd
> like to know, why django cast DATE to DATETIME. Is it a bug?
>
> Currently, I use a workaround:
> {{{
> db_dates = [dt['date'] for dt in
> Model1.objects.order_by('date').values('date').distinct()]
> }}}
New description:
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = Model1.objects.dates("date", kind="day")
}}}
I dumped the django queries.
{{{
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
}}}
As you can see, the query did possibly an unnecessary type cast. The
performance impact is scaled to the amount of records. The table field is
exactly `DATE` type. I don't know, if there is some reason for the type
casting.
Currently, I use a workaround:
{{{
db_dates = Model1.objects.values_list('date', flat=True).distinct()
}}}
I posted a question at [http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
StackOverflow].
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:6>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Description changed by stanleyxu2005:
Old description:
> I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
> (MyISAM). Recently the number of table records reaches 1 million, it will
> take 1-1.5 seconds to query all distinct record dates. But using MySQL
> client, it takes less than 0.001 second.
>
> '''Django Code'''
>
> {{{
> class Model1(models.Model):
> date = models.DateField(db_index=True)
>
> # benchmark code
> db_dates = Model1.objects.dates("date", kind="day")
> }}}
>
> I dumped the django queries.
>
> {{{
> {u'time': u'1.989', u'sql': u"SELECT DISTINCT
> CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
> AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
> ORDER BY `datefield` ASC"}
> }}}
>
> As you can see, the query did possibly an unnecessary type cast. The
> performance impact is scaled to the amount of records. The table field is
> exactly `DATE` type. I don't know, if there is some reason for the type
> casting.
>
> Currently, I use a workaround:
> {{{
> db_dates = Model1.objects.values_list('date', flat=True).distinct()
> }}}
>
> I posted a question at
> [http://stackoverflow.com/questions/32795047/have-a-perforamance-issue-
> of-query-date-object-using-django-queryset StackOverflow].
New description:
I'm using django 1.8.4 writing a webapp. The backend uses MySQL 5.6
(MyISAM). Recently the number of table records reaches 1 million, it will
take 1-1.5 seconds to query all distinct record dates. But using MySQL
client, it takes less than 0.001 second.
'''Django Code'''
{{{
class Model1(models.Model):
date = models.DateField(db_index=True)
# benchmark code
db_dates = Model1.objects.dates("date", kind="day")
}}}
I dumped the django queries.
{{{
{u'time': u'1.989', u'sql': u"SELECT DISTINCT
CAST(DATE_FORMAT(`app1_model1`.`date`, '%Y-%m-%d 00:00:00') AS DATETIME)
AS `datefield` FROM `app1_model1` WHERE `app1_model1`.`date` IS NOT NULL
ORDER BY `datefield` ASC"}
}}}
As you can see, the query did possibly an unnecessary type cast. The
performance impact is scaled to the amount of records. The table field is
exactly `DATE` type. I don't know, if there is some reason for the type
casting.
Currently, I use another query to get these dates, which takes 0.04
second.
{{{
db_dates = Model1.objects.values_list('date', flat=True).distinct()
}}}
I posted a question at [http://stackoverflow.com/questions/32795047/have-a
-perforamance-issue-of-query-date-object-using-django-queryset
StackOverflow].
--
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:7>
Django
dates objects
-------------------------------------+-------------------------------------
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* stage: Unreviewed => Accepted
Comment:
If you'd like to investigate and propose a fix, that would be great!
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:8>
Django
dates objects
-------------------------------------+-------------------------------------
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by stanleyxu2005):
Thanks for agreeing this is a serious performance impact. It is still
unclear, why DATE is first converted to DATETIME. The Django team must
know, whether the code is written by design?
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:9>
Django
dates objects
-------------------------------------+-------------------------------------
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by timgraham):
Did you try modifying the code and seeing if any tests fail? That's often
helpful.
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:10>
Django
dates objects
-------------------------------------+-------------------------------------
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* cc: felisiak.mariusz@… (added)
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:11>
Django
dates objects
-------------------------------------+-------------------------------------
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by stanleyxu2005):
Replying to [comment:10 timgraham]:
> Did you try modifying the code and seeing if any tests fail? That's
often helpful.
My solution just helps me to solve my current problem. Sorry, I don't
realize that when I report issue to django community, I'd provide patch
and do necessary tests. Really sorry about that. Bye
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:12>
Django
dates objects
-------------------------------------+-------------------------------------
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* status: new => assigned
* owner: nobody => felixxm
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:13>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: felixxm
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* has_patch: 0 => 1
Comment:
I made [https://github.com/django/django/pull/5428 PR] to omit unnecessary
type cast.
In my opinion, the second step, is to change default {{{order}}} in
{{{dates}}}, {{{datetimes}}} methods
{{{#!diff
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -726,21 +726,25 @@ class QuerySet(object):
clone._iterable_class = FlatValuesListIterable if flat else
ValuesListIterable
return clone
- def dates(self, field_name, kind, order='ASC'):
+ def dates(self, field_name, kind, order=None):
"""
}}}
or give a way to disable it
{{{#!diff
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -733,14 +733,18 @@ class QuerySet(object):
"""
assert kind in ("year", "month", "day"), \
"'kind' must be one of 'year', 'month' or 'day'."
- assert order in ('ASC', 'DESC'), \
- "'order' must be either 'ASC' or 'DESC'."
- return self.annotate(
+ assert order is None or order in ('ASC', 'DESC'), \
+ "'order' must be either 'ASC', 'DESC' or None."
+ qs = self.annotate(
datefield=Date(field_name, kind),
plain_field=F(field_name)
).values_list(
'datefield', flat=True
- ).distinct().filter(plain_field__isnull=False).order_by(('-' if
order == 'DESC' else '') + 'datefield')
+ ).distinct().filter(plain_field__isnull=False)
+ if order is not None:
+ return qs.order_by(('-' if order == 'DESC' else '') +
'datefield')
+ else:
+ return qs
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:14>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: felixxm
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Comment (by felixxm):
Any suggestions? I can't find any indications of default sort.
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:15>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: felixxm
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by charettes):
* cc: charettes (added)
Comment:
The default sort order of `ASC` seems
[https://docs.djangoproject.com/en/1.8/ref/models/querysets/#dates to be
documented] and simply making results unordered would be backward
incompatible.
I guess you should open a new ticket for a feature request allowing the
use of `order=None` to get unordered results.
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:16>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: felixxm
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by timgraham):
* needs_tests: 0 => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:17>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: felixxm
Type: | Status: assigned
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by felixxm):
* needs_tests: 1 => 0
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:18>
Django
dates objects
-------------------------------------+-------------------------------------
Reporter: stanleyxu2005 | Owner: felixxm
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by Tim Graham <timograham@…>):
* status: assigned => closed
* resolution: => fixed
Comment:
In [changeset:"0f6d51e6a0a22e37e45c4bf452ddb49723e2f956" 0f6d51e6]:
{{{
#!CommitTicketReference repository=""
revision="0f6d51e6a0a22e37e45c4bf452ddb49723e2f956"
Fixed #25470 -- Avoided unnecessary, expensive DATETIME typecast on MySQL.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/25470#comment:19>