diff --git a/test_runner/batch_others/test_timeline_size.py b/test_runner/batch_others/test_timeline_size.py
index 3c58b0b30e..e4dd4de7fb 100644
--- a/test_runner/batch_others/test_timeline_size.py
+++ b/test_runner/batch_others/test_timeline_size.py
@@ -3,6 +3,7 @@ from uuid import UUID
 import psycopg2.extras
 from fixtures.zenith_fixtures import ZenithEnv
 from fixtures.log_helper import log
+import time
 
 
 def test_timeline_size(zenith_simple_env: ZenithEnv):
@@ -35,3 +36,82 @@ def test_timeline_size(zenith_simple_env: ZenithEnv):
 
             res = client.branch_detail(UUID(env.initial_tenant), "test_timeline_size")
             assert res["current_logical_size"] == res["current_logical_size_non_incremental"]
+
+
+def test_timeline_size_quota(zenith_simple_env: ZenithEnv):
+    env = zenith_simple_env
+    env.zenith_cli(["branch", "test_timeline_size_quota", "empty"])
+
+    client = env.pageserver.http_client()
+    res = client.branch_detail(UUID(env.initial_tenant), "test_timeline_size_quota")
+    assert res["current_logical_size"] == res["current_logical_size_non_incremental"]
+
+    pgmain = env.postgres.create_start(
+        "test_timeline_size_quota",
+        config_lines=['zenith.max_cluster_size=25MB'],
+    )
+    log.info("postgres is running on 'test_timeline_size_quota' branch")
+
+    with closing(pgmain.connect()) as conn:
+        with conn.cursor() as cur:
+            cur.execute("SHOW zenith.zenith_timeline")
+
+            cur.execute("CREATE TABLE foo (t text)")
+
+            res = client.branch_detail(UUID(env.initial_tenant), "test_timeline_size_quota")
+            assert res["current_logical_size"] == res["current_logical_size_non_incremental"]
+            current_logical_size = res["current_logical_size"]
+            log.info(f"current_logical_size 1 = {current_logical_size}")
+
+            # Insert many rows. This query must fail because of space limit
+            try:
+                cur.execute('''
+                    INSERT INTO foo
+                        SELECT 'long string to consume some space' || g
+                        FROM generate_series(1, 100000) g
+                ''')
+
+                cur.execute('''
+                    INSERT INTO foo
+                        SELECT 'long string to consume some space' || g
+                        FROM generate_series(1, 100000) g
+                ''')
+
+                # double check: get size from pageserver
+                client = env.pageserver.http_client()
+                res = client.branch_detail(UUID(env.initial_tenant), "test_timeline_size_quota")
+                current_logical_size = res["current_logical_size"]
+                log.info(f"current_logical_size 2 = {current_logical_size}")
+
+                # If we get here, the timeline size limit failed
+                log.error("Query unexpectedly succeeded")
+                assert False
+
+            except Exception as err:
+                log.info(f"Query failed with: {err}")
+                # 53100 is a disk_full errcode
+                assert err.pgcode == '53100'
+
+                # double check: get size from pageserver
+                client = env.pageserver.http_client()
+                res = client.branch_detail(UUID(env.initial_tenant), "test_timeline_size_quota")
+                current_logical_size = res["current_logical_size"]
+                log.info(f"current_logical_size = {current_logical_size}")
+
+            # drop table to free space
+            cur.execute('DROP TABLE foo')
+
+            # create it again and insert some rows. This query must succeed
+            cur.execute("CREATE TABLE foo (t text)")
+            cur.execute('''
+                INSERT INTO foo
+                    SELECT 'long string to consume some space' || g
+                    FROM generate_series(1, 10000) g
+            ''')
+
+            # double check: get size from pageserver
+            client = env.pageserver.http_client()
+            res = client.branch_detail(UUID(env.initial_tenant), "test_timeline_size_quota")
+            current_logical_size = res["current_logical_size"]
+            log.info(f"current_logical_size = {current_logical_size}")
+            assert current_logical_size < 25 * 1024 * 1024
diff --git a/vendor/postgres b/vendor/postgres
index eded7571a3..ab259b5054 160000
--- a/vendor/postgres
+++ b/vendor/postgres
@@ -1 +1 @@
-Subproject commit eded7571a30fd901dac85daccda789337d5be668
+Subproject commit ab259b50544c6912c1e8fc68aec09f7db238c30d