perf(cosmos): add PKRange namedtuple for compact partition key range storage

Convert raw service response dicts to PKRange namedtuples in both
full refresh (_build_routing_map_from_ranges) and incremental update
(process_fetched_ranges) paths. PKRange retains only 4 fields (id,
minInclusive, maxExclusive, parents) and supports dict-style access
for backward compatibility.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: tvaron3

sdk/cosmos/azure-cosmos/azure/cosmos/_routing/_routing_map_provider_common.py

@@ -209,7 +209,11 @@ def process_fetched_ranges(
                 next_unresolved.append(r)
                 continue
 
-            range_tuples.append((r, range_info))
+            range_tuples.append((PKRange(
+                id=r[PartitionKeyRange.Id],
+                minInclusive=r[PartitionKeyRange.MinInclusive],
+                maxExclusive=r[PartitionKeyRange.MaxExclusive],
+                parents=r.get(PartitionKeyRange.Parents)), range_info))
             known_range_info_by_id[r[PartitionKeyRange.Id]] = range_info
             progress_made = True
 

sdk/cosmos/azure-cosmos/azure/cosmos/_routing/collection_routing_map.py

@@ -27,7 +27,7 @@
 from typing import Optional, Union
 
 from azure.cosmos._routing import routing_range
-from azure.cosmos._routing.routing_range import PartitionKeyRange
+from azure.cosmos._routing.routing_range import PartitionKeyRange, PKRange
 
 # pylint: disable=line-too-long
 class CollectionRoutingMap(object):
@@ -288,7 +288,13 @@ def _build_routing_map_from_ranges(
         if PartitionKeyRange.Parents in r and r[PartitionKeyRange.Parents]:
             gone_range_ids.update(r[PartitionKeyRange.Parents])
 
-    filtered_ranges = [r for r in ranges if r[PartitionKeyRange.Id] not in gone_range_ids]
+    filtered_ranges = [
+        PKRange(id=r[PartitionKeyRange.Id],
+                minInclusive=r[PartitionKeyRange.MinInclusive],
+                maxExclusive=r[PartitionKeyRange.MaxExclusive],
+                parents=r.get(PartitionKeyRange.Parents))
+        for r in ranges if r[PartitionKeyRange.Id] not in gone_range_ids
+    ]
     range_tuples = [(r, True) for r in filtered_ranges]
 
     routing_map = CollectionRoutingMap.CompleteRoutingMap(

sdk/cosmos/azure-cosmos/azure/cosmos/_routing/routing_range.py

@@ -27,6 +27,31 @@
 import json
 
 
+from collections import namedtuple
+
+_PKRangeBase = namedtuple('PKRange', ['id', 'minInclusive', 'maxExclusive', 'parents'])
+
+
+class PKRange(_PKRangeBase):
+    """Compact partition key range with dict-compatible access."""
+    __slots__ = ()
+
+    def __getitem__(self, key):
+        try:
+            return getattr(self, key)
+        except AttributeError:
+            raise KeyError(key)
+
+    def get(self, key, default=None):
+        return getattr(self, key, default)
+
+    def __contains__(self, key):
+        return key in self._fields
+
+    def items(self):
+        return zip(self._fields, self)
+
+
 class PartitionKeyRange(object):
     """Partition Key Range Constants"""
 

sdk/cosmos/azure-cosmos/tests/routing/test_shared_pk_range_cache.py

@@ -6,7 +6,7 @@
 
 import pytest
 
-from azure.cosmos._routing.routing_range import Range
+from azure.cosmos._routing.routing_range import Range, PKRange
 from azure.cosmos._routing.collection_routing_map import CollectionRoutingMap
 from azure.cosmos._routing.routing_map_provider import (
     PartitionKeyRangeCache,
@@ -74,6 +74,30 @@ def test_clear_cache_does_not_affect_other_endpoints(self):
         self.assertNotIn("coll1", cache1._collection_routing_map_by_item)
         self.assertIn("coll2", cache2._collection_routing_map_by_item)
 
+
+    def test_pkrange_dict_access(self):
+        """PKRange supports dict-style [key] access."""
+        pkr = PKRange(id="1", minInclusive="00", maxExclusive="FF", parents=["0"])
+        self.assertEqual(pkr["id"], "1")
+        self.assertEqual(pkr["minInclusive"], "00")
+        self.assertEqual(pkr.get("parents"), ["0"])
+        self.assertEqual(pkr.get("_rid", "default"), "default")
+        self.assertIn("id", pkr)
+        self.assertNotIn("_rid", pkr)
+
+    def test_pkrange_in_collection_routing_map(self):
+        """CollectionRoutingMap works with PKRange namedtuples."""
+        pk_ranges = [
+            PKRange(id="0", minInclusive="", maxExclusive="80", parents=None),
+            PKRange(id="1", minInclusive="80", maxExclusive="FF", parents=None),
+        ]
+        crm = CollectionRoutingMap.CompleteRoutingMap(
+            [(r, True) for r in pk_ranges], "test"
+        )
+        self.assertIsNotNone(crm)
+        overlapping = crm.get_overlapping_ranges(Range("", "FF", True, False))
+        self.assertEqual(len(overlapping), 2)
+
     def test_range_has_slots(self):
         r = Range("00", "FF", True, False)
         self.assertFalse(hasattr(r, "__dict__"))