diff --git a/co3/accessor.py b/co3/accessor.py
index a7f941b..ac07414 100644
--- a/co3/accessor.py
+++ b/co3/accessor.py
@@ -19,10 +19,6 @@ class Accessor[C: Component](metaclass=ABCMeta):
     Access wrapper class for complex queries and easy integration with Composer tables.
     Implements high-level access to things like common constrained SELECT queries.
 
-    Parameters:
-        engine: SQLAlchemy engine to use for queries. Engine is initialized dynamically as
-                a property (based on the config) if not provided
-
     Instance variables:
         access_log: time-indexed log of access queries performed
     '''
diff --git a/co3/collector.py b/co3/collector.py
index 44fe2e9..cc977bf 100644
--- a/co3/collector.py
+++ b/co3/collector.py
@@ -105,7 +105,7 @@ class Collector[C: Component]:
 
         return receipt
 
-    def collect_inserts(self, receipts:list[str]|None=None):
+    def collect_inserts(self, receipts: list[str] | None = None):
         '''
         Collect insert-ready dictionaries for the core primitive schema. This method is
         effectively a light wrapper around the File and Note-based collection logic
diff --git a/co3/indexers/relational.py b/co3/indexers/relational.py
new file mode 100644
index 0000000..32b23e1
--- /dev/null
+++ b/co3/indexers/relational.py
@@ -0,0 +1,43 @@
+from co3.indexer import Indexer
+
+
+class RelationalIndexer(Indexer):
+    _cls_select_cache  = {}
+    _cls_groupby_cache = defaultdict(dict)
+    
+    def __init__(self, accessor, cache_select=True, cache_groupby=True):
+        self.accessor = accessor
+
+        # set instance caches; if remains None, methods can't index
+        self._select_cache = None
+        self._groupby_cache = None
+
+        if cache_groupby and not cache_select:
+            raise ValueError('cannot cache groupbys without select caching enabled')
+
+        if cache_select:
+            self._select_cache = self._cls_select_cache
+
+        if cache_groupby:
+            self._groupby_cache = self._cls_groupby_cache
+
+        self._access_lock = threading.Lock()
+
+    def cache_clear(self, group_by_only=False): 
+        self._groupby_cache.clear()
+        if not group_by_only:
+            self._select_cache.clear()
+
+    def cache_block(
+        self,
+        table,
+        **kwargs,
+    ):
+        '''
+        Provide a user-friendly, dynamically re-indexable
+        '''
+        return CacheBlock(
+            indexer = self,
+            table   = table,
+            **kwargs,
+        )
diff --git a/co3/mapper.py b/co3/mapper.py
index 02c87a3..08795cb 100644
--- a/co3/mapper.py
+++ b/co3/mapper.py
@@ -388,6 +388,12 @@ class ComposableMapper[C: ComposableComponent](Mapper[C]):
           automatic discovery structures could help constrain schema definitions to be
           more in-line with the CO3 operational model. That all being said, this is a
           large amount of complexity and should likely be avoided until necessary.
+
+    .. admonition:: Instance variables
+
+        - ``type_compose_cache``: index for previously computed compositions. This index
+                                  is reset if either ``attach`` or ``attach_many`` is
+                                  called to allow possible new type propagation.
     '''
     def __init__(
         self,
@@ -400,6 +406,18 @@ class ComposableMapper[C: ComposableComponent](Mapper[C]):
         self.attr_compose_map = attr_compose_map
         self.coll_compose_map = coll_compose_map
 
+        self.type_compose_cache = {}
+
+    def attach(self, *args, **kwargs):
+        self.type_compose_cache = {}
+
+        super().attach(*args, **kwargs)
+        
+    def attach_many(self, *args, **kwargs):
+        self.type_compose_cache = {}
+
+        super().attach_many(*args, **kwargs)
+
     def compose(
         self,
         co3_ref:       CO3 | type[CO3],
@@ -426,6 +444,9 @@ class ComposableMapper[C: ComposableComponent](Mapper[C]):
         if isinstance(co3_ref, CO3):
             type_ref = co3_ref.__class__
 
+        if type_ref in self.type_compose_cache:
+            return self.type_compose_cache[type_ref]
+
         comp_agg = None
         last_attr_comp = None
         last_coll_comps = None
@@ -489,4 +510,6 @@ class ComposableMapper[C: ComposableComponent](Mapper[C]):
             last_attr_comp = attr_comp
             last_coll_comps = coll_list
 
+        self.type_compose_cache[type_ref] = comp_agg
+
         return comp_agg