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#The MIT License (MIT)
#Copyright (c) 2014 Microsoft Corporation
#Permission is hereby granted, free of charge, to any person obtaining a copy
#of this software and associated documentation files (the "Software"), to deal
#in the Software without restriction, including without limitation the rights
#to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
#copies of the Software, and to permit persons to whom the Software is
#furnished to do so, subject to the following conditions:
#The above copyright notice and this permission notice shall be included in all
#copies or substantial portions of the Software.
#THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
#IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
#FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
#AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
#LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
#OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
#SOFTWARE.
"""Internal class for partition key range cache implementation in the Azure Cosmos database service.
"""
import azure.cosmos.base as base
from azure.cosmos.routing.collection_routing_map import _CollectionRoutingMap
import azure.cosmos.routing.routing_range as routing_range
from azure.cosmos.routing.routing_range import _PartitionKeyRange
class _PartitionKeyRangeCache(object):
'''
_PartitionKeyRangeCache provides list of effective partition key ranges for a collection.
This implementation loads and caches the collection routing map per collection on demand.
'''
def __init__(self, client):
'''
Constructor
'''
self._documentClient = client
# keeps the cached collection routing map by collection id
self._collection_routing_map_by_item = {}
def get_overlapping_ranges(self, collection_link, partition_key_ranges):
'''
Given a partition key range and a collection,
returns the list of overlapping partition key ranges
:param str collection_link:
The name of the collection.
:param list partition_key_range:
List of partition key range.
:return:
List of overlapping partition key ranges.
:rtype: list
'''
cl = self._documentClient
collection_id = base.GetResourceIdOrFullNameFromLink(collection_link)
collection_routing_map = self._collection_routing_map_by_item.get(collection_id)
if collection_routing_map is None:
collection_pk_ranges = list(cl._ReadPartitionKeyRanges(collection_link))
# for large collections, a split may complete between the read partition key ranges query page responses,
# causing the partitionKeyRanges to have both the children ranges and their parents. Therefore, we need
# to discard the parent ranges to have a valid routing map.
collection_pk_ranges = _PartitionKeyRangeCache._discard_parent_ranges(collection_pk_ranges)
collection_routing_map = _CollectionRoutingMap.CompleteRoutingMap([(r, True) for r in collection_pk_ranges], collection_id)
self._collection_routing_map_by_item[collection_id] = collection_routing_map
return collection_routing_map.get_overlapping_ranges(partition_key_ranges)
@staticmethod
def _discard_parent_ranges(partitionKeyRanges):
parentIds = set()
for r in partitionKeyRanges:
if isinstance(r, dict) and _PartitionKeyRange.Parents in r:
for parentId in r[_PartitionKeyRange.Parents]:
parentIds.add(parentId)
return (r for r in partitionKeyRanges if r[_PartitionKeyRange.Id] not in parentIds)
class _SmartRoutingMapProvider(_PartitionKeyRangeCache):
"""
Efficiently uses PartitionKeyRangeCach and minimizes the unnecessary invocation of _CollectionRoutingMap.get_overlapping_ranges()
"""
def __init__(self, client):
super(_SmartRoutingMapProvider, self).__init__(client)
def _second_range_is_after_first_range(self, range1, range2):
if range1.max > range2.min:
##r.min < #previous_r.max
return False
else:
if (range2.min == range2.min and range1.isMaxInclusive and range2.isMinInclusive):
# the inclusive ending endpoint of previous_r is the same as the inclusive beginning endpoint of r
return False
return True
def _is_sorted_and_non_overlapping(self, ranges):
for idx, r in list(enumerate(ranges))[1:]:
previous_r = ranges[idx-1]
if not self._second_range_is_after_first_range(previous_r, r):
return False
return True
def _subtract_range(self, r, partition_key_range):
"""
Evaluates and returns r - partition_key_range
:param dict partition_key_range:
Partition key range.
:param routing_range._Range r: query range.
:return:
The subtract r - partition_key_range.
:rtype: routing_range._Range
"""
left = max(partition_key_range[routing_range._PartitionKeyRange.MaxExclusive], r.min)
if left == r.min:
leftInclusive = r.isMinInclusive
else:
leftInclusive = False
queryRange = routing_range._Range(left, r.max, leftInclusive,
r.isMaxInclusive)
return queryRange
def get_overlapping_ranges(self, collection_link, sorted_ranges):
'''
Given the sorted ranges and a collection,
Returns the list of overlapping partition key ranges
:param str collection_link:
The collection link.
:param (list of routing_range._Range) sorted_ranges: The sorted list of non-overlapping ranges.
:return:
List of partition key ranges.
:rtype: list of dict
:raises ValueError: If two ranges in sorted_ranges overlap or if the list is not sorted
'''
# validate if the list is non-overlapping and sorted
if not self._is_sorted_and_non_overlapping(sorted_ranges):
raise ValueError("the list of ranges is not a non-overlapping sorted ranges")
target_partition_key_ranges = []
it = iter(sorted_ranges)
try:
currentProvidedRange = next(it)
while True:
if (currentProvidedRange.isEmpty()):
# skip and go to the next item\
currentProvidedRange = next(it)
continue
if len(target_partition_key_ranges):
queryRange = self._subtract_range(currentProvidedRange, target_partition_key_ranges[-1])
else:
queryRange = currentProvidedRange
overlappingRanges = _PartitionKeyRangeCache.get_overlapping_ranges(self, collection_link, queryRange)
assert len(overlappingRanges), ("code bug: returned overlapping ranges for queryRange {} is empty".format(queryRange))
target_partition_key_ranges.extend(overlappingRanges)
lastKnownTargetRange = routing_range._Range.PartitionKeyRangeToRange(target_partition_key_ranges[-1])
# the overlapping ranges must contain the requested range
assert currentProvidedRange.max <= lastKnownTargetRange.max, "code bug: returned overlapping ranges {} does not contain the requested range {}".format(overlappingRanges, queryRange)
# the current range is contained in target_partition_key_ranges just move forward
currentProvidedRange = next(it)
while currentProvidedRange.max <= lastKnownTargetRange.max:
# the current range is covered too. just move forward
currentProvidedRange = next(it)
except StopIteration:
# when the iteration is exhausted we get here. There is nothing else to be done
pass
return target_partition_key_ranges
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