diff --git a/hub/common.py b/hub/common.py
index f077c01..4376663 100644
--- a/hub/common.py
+++ b/hub/common.py
@@ -28,6 +28,9 @@ CLAIM_HASH_LEN = 20
 HISTOGRAM_BUCKETS = (
     .005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10.0, 15.0, 20.0, 30.0, 60.0, float('inf')
 )
+SIZE_BUCKETS = (
+    1, 10, 100, 500, 1000, 2000, 4000, 7500, 10000, 15000, 25000, 50000, 75000, 100000, 150000, 250000, float('inf')
+)
 
 CLAIM_TYPES = {
     'stream': 1,
diff --git a/hub/herald/session.py b/hub/herald/session.py
index 7060684..6c5159e 100644
--- a/hub/herald/session.py
+++ b/hub/herald/session.py
@@ -21,7 +21,7 @@ from hub import __version__, PROMETHEUS_NAMESPACE
 from hub.herald import PROTOCOL_MIN, PROTOCOL_MAX, HUB_PROTOCOL_VERSION
 from hub.build_info import BUILD, COMMIT_HASH, DOCKER_TAG
 from hub.herald.search import SearchIndex
-from hub.common import sha256, hash_to_hex_str, hex_str_to_hash, HASHX_LEN, version_string, formatted_time
+from hub.common import sha256, hash_to_hex_str, hex_str_to_hash, HASHX_LEN, version_string, formatted_time, SIZE_BUCKETS
 from hub.common import protocol_version, RPCError, DaemonError, TaskGroup, HISTOGRAM_BUCKETS, LRUCache, LRUCacheWithMetrics
 from hub.herald.jsonrpc import JSONRPCAutoDetect, JSONRPCConnection, JSONRPCv2, JSONRPC
 from hub.herald.common import BatchRequest, ProtocolError, Request, Batch, Notification
@@ -146,7 +146,6 @@ class SessionManager:
     pending_query_metric = Gauge(
         "pending_queries_count", "Number of pending and running sqlite queries", namespace=NAMESPACE
     )
-
     client_version_metric = Counter(
         "clients", "Number of connections received per client version",
         namespace=NAMESPACE, labelnames=("version",)
@@ -155,6 +154,14 @@ class SessionManager:
         "address_history", "Time to fetch an address history",
         namespace=NAMESPACE, buckets=HISTOGRAM_BUCKETS
     )
+    address_subscription_metric = Gauge(
+        "address_subscriptions", "Number of subscribed addresses",
+        namespace=NAMESPACE
+    )
+    address_history_size_metric = Histogram(
+        "history_size", "Sizes of histories for subscribed addresses",
+        namespace=NAMESPACE, buckets=SIZE_BUCKETS
+    )
     notifications_in_flight_metric = Gauge(
         "notifications_in_flight", "Count of notifications in flight",
         namespace=NAMESPACE
@@ -596,13 +603,16 @@ class SessionManager:
         return hex_hash
 
     async def limited_history(self, hashX: bytes) -> typing.List[typing.Tuple[str, int]]:
-        if hashX in self.hashX_full_cache:
-            return self.hashX_full_cache[hashX]
+        cached_full_history = self.hashX_full_cache.get(hashX)
+        if cached_full_history is not None:
+            self.address_history_size_metric.observe(len(cached_full_history))
+            return cached_full_history
         if hashX not in self.hashX_history_cache:
             limit = self.env.max_send // 97
             self.hashX_history_cache[hashX] = tx_nums = await self.db.read_history(hashX, limit)
         else:
             tx_nums = self.hashX_history_cache[hashX]
+        self.address_history_size_metric.observe(len(tx_nums))
         needed_tx_infos = []
         append_needed_tx_info = needed_tx_infos.append
         tx_infos = {}
@@ -653,6 +663,7 @@ class SessionManager:
     def remove_session(self, session):
         """Remove a session from our sessions list if there."""
         session_id = id(session)
+        self.address_subscription_metric.dec(len(session.hashX_subs))
         for hashX in session.hashX_subs:
             sessions = self.hashx_subscriptions_by_session[hashX]
             sessions.remove(session_id)
@@ -1378,6 +1389,8 @@ class LBRYElectrumX(asyncio.Protocol):
             sessions.remove(id(self))
         except KeyError:
             pass
+        else:
+            self.session_manager.address_subscription_metric.dec()
         if not sessions:
             self.hashX_subs.pop(hashX, None)
 
@@ -1415,6 +1428,7 @@ class LBRYElectrumX(asyncio.Protocol):
         if len(addresses) > 1000:
             raise RPCError(BAD_REQUEST, f'too many addresses in subscription request: {len(addresses)}')
         results = []
+        self.session_manager.address_subscription_metric.inc(len(addresses))
         for address in addresses:
             results.append(await self.hashX_subscribe(self.address_to_hashX(address), address))
             await asyncio.sleep(0)
@@ -1473,6 +1487,7 @@ class LBRYElectrumX(asyncio.Protocol):
 
         scripthash: the SHA256 hash of the script to subscribe to"""
         hashX = scripthash_to_hashX(scripthash)
+        self.session_manager.address_subscription_metric.inc()
         return await self.hashX_subscribe(hashX, scripthash)
 
     async def scripthash_unsubscribe(self, scripthash: str):