Don't hit DB for noop replications queries

4 files changed, 12 insertions, 0 deletions

diff --git a/synapse/storage/account_data.py b/synapse/storage/account_data.py
index ec7e8d40d2..3fa226e92d 100644
--- a/synapse/storage/account_data.py
+++ b/synapse/storage/account_data.py
@@ -138,6 +138,9 @@ class AccountDataStore(SQLBaseStore):
             A deferred pair of lists of tuples of stream_id int, user_id string,
             room_id string, type string, and content string.
         """
+        if last_room_id == current_id and last_global_id == current_id:
+            return defer.succeed(([], []))
+
         def get_updated_account_data_txn(txn):
             sql = (
                 "SELECT stream_id, user_id, account_data_type, content"
diff --git a/synapse/storage/presence.py b/synapse/storage/presence.py
index 3fab57a7e8..d03f7c541e 100644
--- a/synapse/storage/presence.py
+++ b/synapse/storage/presence.py
@@ -118,6 +118,9 @@ class PresenceStore(SQLBaseStore):
             )
 
     def get_all_presence_updates(self, last_id, current_id):
+        if last_id == current_id:
+            return defer.succeed([])
+
         def get_all_presence_updates_txn(txn):
             sql = (
                 "SELECT stream_id, user_id, state, last_active_ts,"
diff --git a/synapse/storage/push_rule.py b/synapse/storage/push_rule.py
index 786d6f6d67..8183b7f1b0 100644
--- a/synapse/storage/push_rule.py
+++ b/synapse/storage/push_rule.py
@@ -421,6 +421,9 @@ class PushRuleStore(SQLBaseStore):
 
     def get_all_push_rule_updates(self, last_id, current_id, limit):
         """Get all the push rules changes that have happend on the server"""
+        if last_id == current_id:
+            return defer.succeed([])
+
         def get_all_push_rule_updates_txn(txn):
             sql = (
                 "SELECT stream_id, event_stream_ordering, user_id, rule_id,"
diff --git a/synapse/storage/tags.py b/synapse/storage/tags.py
index 9da23f34cb..5a2c1aa59b 100644
--- a/synapse/storage/tags.py
+++ b/synapse/storage/tags.py
@@ -68,6 +68,9 @@ class TagsStore(SQLBaseStore):
             A deferred list of tuples of stream_id int, user_id string,
             room_id string, tag string and content string.
         """
+        if last_id == current_id:
+            defer.returnValue([])
+
         def get_all_updated_tags_txn(txn):
             sql = (
                 "SELECT stream_id, user_id, room_id"