Infinidat/infi.clickhouse_orm
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Merge branch 'carrotquest-qs-prewhere' into develop

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Itai Shirav 2019-02-27 08:42:33 +02:00
commit 61107d0d02
6 changed files with 162 additions and 75 deletions
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1
CHANGELOG.md
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@ -3,6 +3,7 @@ Change Log
Unreleased
----------
- Add PREWHERE support to querysets (M1hacka)
- Extend date field range (trthhrtz)
- Fix parsing of server errors in ClickHouse v19.3.3+
- Fix pagination when asking for the last page on a query that matches no records

28
docs/class_reference.md
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@ -835,10 +835,10 @@ is equivalent to:
Returns the whole query as a SQL string.
#### conditions_as_sql()
#### conditions_as_sql(prewhere=False)
Returns the contents of the query's `WHERE` clause as a string.
Returns the contents of the query's `WHERE` or `PREWHERE` clause as a string.
#### count()
@ -854,17 +854,18 @@ Adds a DISTINCT clause to the query, meaning that any duplicate rows
in the results will be omitted.
#### exclude(**filter_fields)
#### exclude(*q, **kwargs)
Returns a copy of this queryset that excludes all rows matching the conditions.
Pass `prewhere=True` to apply the conditions as PREWHERE instead of WHERE.
#### filter(*q, **filter_fields)
#### filter(*q, **kwargs)
Returns a copy of this queryset that includes only rows matching the conditions.
Add q object to query if it specified.
Pass `prewhere=True` to apply the conditions as PREWHERE instead of WHERE.
#### final()
@ -908,6 +909,9 @@ The result is a namedtuple containing `objects` (list), `number_of_objects`,
`pages_total`, `number` (of the current page), and `page_size`.
#### select_fields_as_sql()
### AggregateQuerySet
Extends QuerySet
@ -943,10 +947,10 @@ This method is not supported on `AggregateQuerySet`.
Returns the whole query as a SQL string.
#### conditions_as_sql()
#### conditions_as_sql(prewhere=False)
Returns the contents of the query's `WHERE` clause as a string.
Returns the contents of the query's `WHERE` or `PREWHERE` clause as a string.
#### count()
@ -962,17 +966,18 @@ Adds a DISTINCT clause to the query, meaning that any duplicate rows
in the results will be omitted.
#### exclude(**filter_fields)
#### exclude(*q, **kwargs)
Returns a copy of this queryset that excludes all rows matching the conditions.
Pass `prewhere=True` to apply the conditions as PREWHERE instead of WHERE.
#### filter(*q, **filter_fields)
#### filter(*q, **kwargs)
Returns a copy of this queryset that includes only rows matching the conditions.
Add q object to query if it specified.
Pass `prewhere=True` to apply the conditions as PREWHERE instead of WHERE.
#### final()
@ -1022,3 +1027,6 @@ The result is a namedtuple containing `objects` (list), `number_of_objects`,
`pages_total`, `number` (of the current page), and `page_size`.
#### select_fields_as_sql()

8
docs/querysets.md
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@ -32,6 +32,14 @@ For filters with compound conditions you can use `Q` objects inside `filter` wit
>>> qs.conditions_as_sql()
u"((first_name = 'Ciaran' AND last_name = 'Carver') OR height <= 1.8) AND (NOT (first_name = 'David'))"
By default conditions from `filter` and `exclude` methods are add to `WHERE` clause.
For better aggregation performance you can add them to `PREWHERE` section using `prewhere=True` parameter
>>> qs = Person.objects_in(database)
>>> qs = qs.filter(first_name__startswith='V', prewhere=True)
>>> qs.conditions_as_sql(prewhere=True)
u"first_name LIKE 'V%'"
There are different operators that can be used, by passing `<fieldname>__<operator>=<value>` (two underscores separate the field name from the operator). In case no operator is given, `eq` is used by default. Below are all the supported operators.
| Operator | Equivalent SQL | Comments |

4
docs/ref.md
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@ -482,9 +482,9 @@ infi.clickhouse_orm.query
#### QuerySet(model_cls, database)
#### conditions_as_sql()
#### conditions_as_sql(prewhere=True)
Return the contents of the queryset's WHERE clause.
Return the contents of the queryset's WHERE or `PREWHERE` clause.
#### count()

187
src/infi/clickhouse_orm/query.py
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@ -2,7 +2,7 @@ from __future__ import unicode_literals
import six
import pytz
from copy import copy
from copy import copy, deepcopy
from math import ceil
from .engines import CollapsingMergeTree
@ -173,6 +173,11 @@ class FOV(object):
def to_sql(self, model_cls):
return self._operator.to_sql(model_cls, self._field_name, self._value)
def __deepcopy__(self, memodict={}):
res = copy(self)
res._value = deepcopy(self._value)
return res
class Q(object):
@ -181,17 +186,32 @@ class Q(object):
def __init__(self, **filter_fields):
self._fovs = [self._build_fov(k, v) for k, v in six.iteritems(filter_fields)]
self._l_child = None
self._r_child = None
self._children = []
self._negate = False
self._mode = self.AND_MODE
@property
def is_empty(self):
"""
Checks if there are any conditions in Q object
:return: Boolean
"""
return not bool(self._fovs or self._children)
@classmethod
def _construct_from(cls, l_child, r_child, mode):
q = Q()
q._l_child = l_child
q._r_child = r_child
q._mode = mode # AND/OR
if mode == l_child._mode:
q = deepcopy(l_child)
q._children.append(deepcopy(r_child))
elif mode == r_child._mode:
q = deepcopy(r_child)
q._children.append(deepcopy(l_child))
else:
# Different modes
q = Q()
q._children = [l_child, r_child]
q._mode = mode # AND/OR
return q
def _build_fov(self, key, value):
@ -202,16 +222,27 @@ class Q(object):
return FOV(field_name, operator, value)
def to_sql(self, model_cls):
condition_sql = []
if self._fovs:
sql = ' {} '.format(self._mode).join(fov.to_sql(model_cls) for fov in self._fovs)
condition_sql.extend([fov.to_sql(model_cls) for fov in self._fovs])
if self._children:
condition_sql.extend([child.to_sql(model_cls) for child in self._children if child])
if not condition_sql:
# Empty Q() object returns everything
sql = '1'
elif len(condition_sql) == 1:
# Skip not needed brackets over single condition
sql = condition_sql[0]
else:
if self._l_child and self._r_child:
sql = '({} {} {})'.format(
self._l_child.to_sql(model_cls), self._mode, self._r_child.to_sql(model_cls))
else:
return '1'
# Each condition must be enclosed in brackets, or order of operations may be wrong
sql = '(%s)' % ') {} ('.format(self._mode).join(condition_sql)
if self._negate:
sql = 'NOT (%s)' % sql
return sql
def __or__(self, other):
@ -225,6 +256,20 @@ class Q(object):
q._negate = True
return q
def __bool__(self):
return not self.is_empty
def __deepcopy__(self, memodict={}):
q = Q()
q._fovs = [deepcopy(fov) for fov in self._fovs]
q._negate = self._negate
q._mode = self._mode
if self._children:
q._children = [deepcopy(child) for child in self._children]
return q
@six.python_2_unicode_compatible
class QuerySet(object):
@ -242,7 +287,9 @@ class QuerySet(object):
self._model_cls = model_cls
self._database = database
self._order_by = []
self._q = []
self._where_q = Q()
self._prewhere_q = Q()
self._grouping_fields = []
self._fields = model_cls.fields().keys()
self._limits = None
self._distinct = False
@ -284,20 +331,35 @@ class QuerySet(object):
qs._limits = (start, stop - start)
return qs
def select_fields_as_sql(self):
return comma_join('`%s`' % field for field in self._fields) if self._fields else '*'
def as_sql(self):
"""
Returns the whole query as a SQL string.
"""
distinct = 'DISTINCT ' if self._distinct else ''
fields = '*'
if self._fields:
fields = comma_join('`%s`' % field for field in self._fields)
ordering = '\nORDER BY ' + self.order_by_as_sql() if self._order_by else ''
limit = '\nLIMIT %d, %d' % self._limits if self._limits else ''
final = ' FINAL' if self._final else ''
params = (distinct, fields, self._model_cls.table_name(), final,
self.conditions_as_sql(), ordering, limit)
return u'SELECT %s%s\nFROM `%s`%s\nWHERE %s%s%s' % params
params = (distinct, self.select_fields_as_sql(), self._model_cls.table_name(), final)
sql = u'SELECT %s%s\nFROM `%s`%s' % params
if self._prewhere_q and not self._prewhere_q.is_empty:
sql += '\nPREWHERE ' + self.conditions_as_sql(prewhere=True)
if self._where_q and not self._where_q.is_empty:
sql += '\nWHERE ' + self.conditions_as_sql(prewhere=False)
if self._grouping_fields:
sql += '\nGROUP BY %s' % comma_join('`%s`' % field for field in self._grouping_fields)
if self._order_by:
sql += '\nORDER BY ' + self.order_by_as_sql()
if self._limits:
sql += '\nLIMIT %d, %d' % self._limits
return sql
def order_by_as_sql(self):
"""
@ -308,14 +370,12 @@ class QuerySet(object):
for field in self._order_by
])
def conditions_as_sql(self):
def conditions_as_sql(self, prewhere=False):
"""
Returns the contents of the query's `WHERE` clause as a string.
Returns the contents of the query's `WHERE` or `PREWHERE` clause as a string.
"""
if self._q:
return u' AND '.join([q.to_sql(self._model_cls) for q in self._q])
else:
return u'1'
q_object = self._prewhere_q if prewhere else self._where_q
return q_object.to_sql(self._model_cls)
def count(self):
"""
@ -326,8 +386,10 @@ class QuerySet(object):
sql = u'SELECT count() FROM (%s)' % self.as_sql()
raw = self._database.raw(sql)
return int(raw) if raw else 0
# Simple case
return self._database.count(self._model_cls, self.conditions_as_sql())
conditions = (self._where_q & self._prewhere_q).to_sql(self._model_cls)
return self._database.count(self._model_cls, conditions)
def order_by(self, *field_names):
"""
@ -347,25 +409,43 @@ class QuerySet(object):
qs._fields = field_names
return qs
def filter(self, *q, **filter_fields):
"""
Returns a copy of this queryset that includes only rows matching the conditions.
Add q object to query if it specified.
"""
def _filter_or_exclude(self, *q, **kwargs):
inverse = kwargs.pop('_inverse', False)
prewhere = kwargs.pop('prewhere', False)
qs = copy(self)
if q:
qs._q = list(self._q) + list(q)
condition = Q()
for q_obj in q:
condition &= q_obj
if kwargs:
condition &= Q(**kwargs)
if inverse:
condition = ~condition
condition = copy(self._prewhere_q if prewhere else self._where_q) & condition
if prewhere:
qs._prewhere_q = condition
else:
qs._q = list(self._q) + [Q(**filter_fields)]
qs._where_q = condition
return qs
def exclude(self, **filter_fields):
def filter(self, *q, **kwargs):
"""
Returns a copy of this queryset that includes only rows matching the conditions.
Pass `prewhere=True` to apply the conditions as PREWHERE instead of WHERE.
"""
return self._filter_or_exclude(*q, **kwargs)
def exclude(self, *q, **kwargs):
"""
Returns a copy of this queryset that excludes all rows matching the conditions.
Pass `prewhere=True` to apply the conditions as PREWHERE instead of WHERE.
"""
qs = copy(self)
qs._q = list(self._q) + [~Q(**filter_fields)]
return qs
return self._filter_or_exclude(*q, _inverse=True, **kwargs)
def paginate(self, page_num=1, page_size=100):
"""
@ -459,7 +539,8 @@ class AggregateQuerySet(QuerySet):
self._grouping_fields = grouping_fields
self._calculated_fields = calculated_fields
self._order_by = list(base_qs._order_by)
self._q = list(base_qs._q)
self._where_q = base_qs._where_q
self._prewhere_q = base_qs._prewhere_q
self._limits = base_qs._limits
self._distinct = base_qs._distinct
@ -488,26 +569,8 @@ class AggregateQuerySet(QuerySet):
"""
raise NotImplementedError('Cannot re-aggregate an AggregateQuerySet')
def as_sql(self):
"""
Returns the whole query as a SQL string.
"""
distinct = 'DISTINCT ' if self._distinct else ''
grouping = comma_join('`%s`' % field for field in self._grouping_fields)
fields = comma_join(list(self._fields) + ['%s AS %s' % (v, k) for k, v in self._calculated_fields.items()])
params = dict(
distinct=distinct,
grouping=grouping or "''",
fields=fields,
table=self._model_cls.table_name(),
conds=self.conditions_as_sql()
)
sql = u'SELECT %(distinct)s%(fields)s\nFROM `%(table)s`\nWHERE %(conds)s\nGROUP BY %(grouping)s' % params
if self._order_by:
sql += '\nORDER BY ' + self.order_by_as_sql()
if self._limits:
sql += '\nLIMIT %d, %d' % self._limits
return sql
def select_fields_as_sql(self):
return comma_join(list(self._fields) + ['%s AS %s' % (v, k) for k, v in self._calculated_fields.items()])
def __iter__(self):
return self._database.select(self.as_sql()) # using an ad-hoc model

9
tests/test_querysets.py
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@ -11,7 +11,7 @@ from datetime import date, datetime
try:
Enum # exists in Python 3.4+
except NameError:
from enum import Enum # use the enum34 library instead
from enum import Enum # use the enum34 library instead
class QuerySetTestCase(TestCaseWithData):
@ -29,6 +29,13 @@ class QuerySetTestCase(TestCaseWithData):
self.assertEqual(count, expected_count)
self.assertEqual(qs.count(), expected_count)
def test_prewhere(self):
# We can't distinguish prewhere and where results, it affects performance only.
# So let's control prewhere acts like where does
qs = Person.objects_in(self.database)
self.assertTrue(qs.filter(first_name='Connor', prewhere=True))
self.assertFalse(qs.filter(first_name='Willy', prewhere=True))
def test_no_filtering(self):
qs = Person.objects_in(self.database)
self._test_qs(qs, len(data))