Merge pull request #6148 from matrix-org/erikj/find_next_generated

matrix-org · Feb 26, 2020 · dc68d85 · dc68d85
2 parents 9f7acf6 + 5d8ffdf
commit dc68d85
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diff --git a/changelog.d/6148.misc b/changelog.d/6148.misc
@@ -0,0 +1 @@
+Improve performance of `find_next_generated_user_id` DB query.
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
@@ -515,7 +515,9 @@ def find_next_generated_user_id_localpart(self):
         """
 
         def _find_next_generated_user_id(txn):
-            txn.execute("SELECT name FROM users")
+            # We bound between '@1' and '@a' to avoid pulling the entire table
+            # out.
+            txn.execute("SELECT name FROM users WHERE '@1' <= name AND name < '@a'")
 
             regex = re.compile(r"^@(\d+):")
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Improve performance of `find_next_generated_user_id` DB query.