carrotquest/django-clickhouse
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get_final_versions fixes (#38)

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1. Fixed problem when get_final_version() could return 2 rows instead of 1 and insert multiple sign < 0 rows with single sign > 0
2. Fixed problem from PR https://github.com/carrotquest/django-clickhouse/pull/37, when date_col is not set for ClickHouseModel
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M1ha Shvn 2021-10-06 10:01:45 +05:00 committed by GitHub
parent 12069db14e
commit 0e65f15333
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3 changed files with 97 additions and 34 deletions
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2
setup.py
View File

@ -13,7 +13,7 @@ with open('requirements.txt') as f:
setup(
name='django-clickhouse',
version='1.1.1',
version='1.1.2',
packages=['django_clickhouse', 'django_clickhouse.management.commands'],
package_dir={'': 'src'},
url='https://github.com/carrotquest/django-clickhouse',

114
src/django_clickhouse/engines.py
View File

@ -2,7 +2,8 @@
This file contains wrappers for infi.clckhouse_orm engines to use in django-clickhouse
"""
import datetime
from typing import List, Type, Union, Iterable, Optional
import logging
from typing import List, Type, Union, Iterable, Optional, Tuple, NamedTuple
from django.db.models import Model as DjangoModel
from infi.clickhouse_orm import engines as infi_engines
@ -14,6 +15,9 @@ from .database import connections
from .utils import format_datetime
logger = logging.getLogger('django-clickhouse')
class InsertOnlyEngineMixin:
def get_insert_batch(self, model_cls: Type[ClickHouseModel], objects: List[DjangoModel]) -> Iterable[tuple]:
"""
@ -45,43 +49,64 @@ class CollapsingMergeTree(InsertOnlyEngineMixin, infi_engines.CollapsingMergeTre
self.version_col = kwargs.pop('version_col', None)
super(CollapsingMergeTree, self).__init__(*args, **kwargs)
def _get_final_versions_by_version(self, db_alias, model_cls, min_date, max_date, object_pks, date_col, columns):
def _get_final_versions_by_version(self, db_alias: str, model_cls: Type[ClickHouseModel], object_pks: Iterable[str],
columns: str, date_range_filter: str = '') -> List[NamedTuple]:
"""
Performs request to ClickHouse in order to fetch latest version for each object pk
:param db_alias: ClickHouse database alias used
:param model_cls: Model class for which data is fetched
:param object_pks: Objects primary keys to filter by
:param columns: Columns to fetch
:param date_range_filter: Optional date_range_filter which speeds up query if date_col is set
:return: List of named tuples with requested columns
"""
if date_range_filter:
date_range_filter = 'PREWHERE {}'.format(date_range_filter)
query = """
SELECT {columns} FROM $table WHERE (`{pk_column}`, `{version_col}`) IN (
SELECT `{pk_column}`, MAX(`{version_col}`)
SELECT {columns}
FROM $table
PREWHERE `{date_col}` >= '{min_date}' AND `{date_col}` <= '{max_date}'
AND `{pk_column}` IN ({object_pks})
GROUP BY `{pk_column}`
)
""".format(columns=','.join(columns), version_col=self.version_col, date_col=date_col, pk_column=self.pk_column,
min_date=min_date, max_date=max_date, object_pks=','.join(object_pks))
{date_range_filter}
WHERE `{pk_column}` IN ({object_pks})
ORDER BY `{pk_column}`, `{version_col}` DESC
LIMIT 1 BY `{pk_column}`
""".format(columns=','.join(columns), version_col=self.version_col, pk_column=self.pk_column,
date_range_filter=date_range_filter, object_pks=','.join(object_pks), sign_col=self.sign_col)
return connections[db_alias].select_tuples(query, model_cls)
def _get_final_versions_by_final(self, db_alias, model_cls, min_date, max_date, object_pks, date_col, columns):
def _get_final_versions_by_final(self, db_alias: str, model_cls: Type[ClickHouseModel], object_pks: Iterable[str],
columns: str, date_range_filter: str = '') -> List[NamedTuple]:
"""
Performs request to ClickHouse in order to fetch latest version for each object pk
:param db_alias: ClickHouse database alias used
:param model_cls: Model class for which data is fetched
:param object_pks: Objects primary keys to filter by
:param columns: Columns to fetch
:param date_range_filter: Optional date_range_filter which speeds up query if date_col is set
:return: List of named tuples with requested columns
"""
if date_range_filter:
date_range_filter += ' AND'
query = """
SELECT {columns} FROM $table FINAL
WHERE `{date_col}` >= '{min_date}' AND `{date_col}` <= '{max_date}'
AND `{pk_column}` IN ({object_pks})
WHERE {date_range_filter} `{pk_column}` IN ({object_pks})
"""
query = query.format(columns=','.join(columns), date_col=date_col, pk_column=self.pk_column, min_date=min_date,
max_date=max_date, object_pks=','.join(object_pks))
query = query.format(columns=','.join(columns), pk_column=self.pk_column, date_range_filter=date_range_filter,
object_pks=','.join(object_pks))
return connections[db_alias].select_tuples(query, model_cls)
def get_final_versions(self, model_cls: Type[ClickHouseModel], objects: Iterable[DjangoModel],
date_col: Optional[str] = None) -> Iterable[tuple]:
def _get_date_rate_filter(self, objects, model_cls: Type[ClickHouseModel], db_alias: str,
date_col: Optional[str]) -> str:
"""
Get objects, that are currently stored in ClickHouse.
Depending on the partition key this can be different for different models.
In common case, this method is optimized for date field that doesn't change.
It also supposes primary key to by self.pk_column
:param model_cls: ClickHouseModel subclass to import
:param objects: Objects for which final versions are searched
:param date_col: Optional column name, where partiion date is hold. Defaults to self.date_col
:return: A generator of named tuples, representing previous state
Generates datetime filter to speed up final queries, if date_col is present
:param objects: Objects, which are inserted
:param model_cls: Model class for which data is fetched
:param db_alias: ClickHouse database alias used
:param date_col: Optional column name, where partition date is hold. Defaults to self.date_col
:return: String to add to WHERE or PREWHERE query section
"""
def _dt_to_str(dt: Union[datetime.date, datetime.datetime]) -> str:
if isinstance(dt, datetime.datetime):
return format_datetime(dt, 0, db_alias=db_alias)
@ -90,10 +115,15 @@ class CollapsingMergeTree(InsertOnlyEngineMixin, infi_engines.CollapsingMergeTre
else:
raise Exception('Invalid date or datetime object: `%s`' % dt)
if not objects:
raise StopIteration()
date_col = date_col or self.date_col
if not date_col:
logger.warning('django-clickhouse: date_col is not provided for model %s.'
' This can cause significant performance problems while fetching data.'
' It is worth inheriting CollapsingMergeTree engine with custom get_final_versions() method,'
' based on your partition_key' % model_cls)
return ''
min_date, max_date = None, None
for obj in objects:
obj_date = getattr(obj, date_col)
@ -104,19 +134,39 @@ class CollapsingMergeTree(InsertOnlyEngineMixin, infi_engines.CollapsingMergeTre
if max_date is None or max_date < obj_date:
max_date = obj_date
min_date = _dt_to_str(min_date)
max_date = _dt_to_str(max_date)
return "`{date_col}` >= '{min_date}' AND `{date_col}` <= '{max_date}'".\
format(min_date=min_date, max_date=max_date, date_col=date_col)
def get_final_versions(self, model_cls: Type[ClickHouseModel], objects: Iterable[DjangoModel],
date_col: Optional[str] = None) -> Iterable[tuple]:
"""
Get objects, that are currently stored in ClickHouse.
Depending on the partition key this can be different for different models.
In common case, this method is optimized for date field that doesn't change.
It also supposes primary key to by self.pk_column
:param model_cls: ClickHouseModel subclass to import
:param objects: Objects for which final versions are searched
:param date_col: Optional column name, where partition date is hold. Defaults to self.date_col
:return: A generator of named tuples, representing previous state
"""
if not objects:
raise StopIteration()
object_pks = [str(getattr(obj, self.pk_column)) for obj in objects]
db_alias = model_cls.get_database_alias()
min_date = _dt_to_str(min_date)
max_date = _dt_to_str(max_date)
date_range_filter = self._get_date_rate_filter(objects, model_cls, db_alias, date_col)
# Get fields. Sign is replaced to negative for further processing
columns = list(model_cls.fields(writable=True).keys())
columns.remove(self.sign_col)
columns.append('-1 AS sign')
params = (db_alias, model_cls, min_date, max_date, object_pks, date_col, columns)
params = (db_alias, model_cls, object_pks, columns, date_range_filter)
if self.version_col:
return self._get_final_versions_by_version(*params)

13
tests/test_engines.py
View File

@ -88,12 +88,25 @@ class CollapsingMergeTreeTest(TestCase):
self.objects, date_col='created')
self._test_final_versions(final_versions)
def test_get_final_versions_by_final_no_date_col(self):
ClickHouseCollapseTestModel.engine.date_col = None
final_versions = ClickHouseCollapseTestModel.engine.get_final_versions(ClickHouseCollapseTestModel,
self.objects)
self._test_final_versions(final_versions)
def test_get_final_versions_by_version_datetime(self):
ClickHouseCollapseTestModel.engine.version_col = 'version'
final_versions = ClickHouseCollapseTestModel.engine.get_final_versions(ClickHouseCollapseTestModel,
self.objects, date_col='created')
self._test_final_versions(final_versions)
def test_get_final_versions_by_version_no_date_col(self):
ClickHouseCollapseTestModel.engine.version_col = 'version'
ClickHouseCollapseTestModel.engine.date_col = None
final_versions = ClickHouseCollapseTestModel.engine.get_final_versions(ClickHouseCollapseTestModel,
self.objects)
self._test_final_versions(final_versions)
def test_versions(self):
ClickHouseCollapseTestModel.engine.version_col = 'version'
batch = ClickHouseCollapseTestModel.get_insert_batch(self.objects)