Finished the test draft for ATTACH PARTITION,

Extracted the part data corruption function into the helper.

tests/integration/helpers/corrupt_part_data_on_disk.py

@@ -0,0 +1,7 @@
+def corrupt_part_data_on_disk(node, table, part_name, is_detached=False):
+    parts_table = "system.detached_parts" is is_detached else "system.parts"
+    part_path = node.query(
+        "SELECT path FROM " + parts_table + " WHERE table = '{}' and name = '{}'".format(table, part_name)).strip()
+    node.exec_in_container(['bash', '-c',
+                            'cd {p} && ls *.bin | head -n 1 | xargs -I{{}} sh -c \'echo "1" >> $1\' -- {{}}'.format(
+                                p=part_path)], privileged=True)

tests/integration/test_attach_without_fetching/configs/remote_servers.xml

@@ -0,0 +1,21 @@
+<yandex>
+    <remote_servers>
+        <test_cluster>
+            <shard>
+                <internal_replication>true</internal_replication>
+                <replica>
+                    <host>node_1_1</host>
+                    <port>9000</port>
+                </replica>
+                <replica>
+                    <host>node_1_2</host>
+                    <port>9000</port>
+                </replica>
+                 <replica>
+                    <host>node_1_3</host>
+                    <port>9000</port>
+                </replica>
+            </shard>
+        </test_cluster>
+    </remote_servers>
+</yandex>

tests/integration/test_attach_without_fetching/test.py

@@ -1,49 +1,98 @@
+import time
 import pytest
+
 from helpers.cluster import ClickHouseCluster
+from helpers.cluster import ClickHouseKiller
+from helpers.test_tools import assert_eq_with_retry
+from helpers.network import PartitionManager
+from helpers.corrupt_part_data_on_disk import corrupt_part_data_on_disk
+
+def fill_node(node):
+    node.query(
+    '''
+        CREATE TABLE test(n UInt32)
+        ENGINE = ReplicatedMergeTree('/clickhouse/tables/test', '{replica}')
+        ORDER BY n PARTITION BY n % 10;
+    '''.format(replica=node.name))
 
 cluster = ClickHouseCluster(__file__)
+configs =["configs/remote_servers.xml"]
 
-node1 = cluster.add_instance('node1')
-
+node_1 = cluster.add_instance('replica1', with_zookeeper=True, main_configs=configs)
+node_2 = cluster.add_instance('replica2', with_zookeeper=True, main_configs=configs)
+node_3 = cluster.add_instance('replica3', with_zookeeper=True, main_configs=configs)
 
 @pytest.fixture(scope="module")
 def start_cluster():
     try:
         cluster.start()
-
+        fill_node(node_1)
+        fill_node(node_2)
+        # the third node is filled after the DETACH query
         yield cluster
+
+    except Exception as ex:
+        print(ex)
+
     finally:
         cluster.shutdown()
 
+def check_data(nodes, detached_parts):
+    for node in nodes:
+        for i in range(10):
+            assert node.query("SELECT count() FROM test WHERE key % 10 == " + str(i)) ==
+                "0\n" if i in detached_parts else "10\n"
 
-# Check that ALTER TABLE ATTACH PARTITION does not fetch data from other replicas if it's present in the
-# detached/ folder
+        assert node.query("SELECT count() FROM system.parts WHERE table='test'") ==
+            str(10 - len(detached_parts)) + "\n"
+
+        assert node.query("SELECT count() FROM system.detached_parts WHERE table='test'") ==
+            str(len(detached_parts)) + "\n"
+
+# 1. Check that ALTER TABLE ATTACH PARTITION does not fetch data from other replicas if it's present in the
+# detached/ folder.
+# 2. Check that ALTER TABLE ATTACH PARTITION downloads the data from other replicas if the detached/ folder
+# does not contain the part with the correct checksums.
 def test_attach_without_fetching(start_cluster):
-    node1.query(
-        "CREATE TABLE test (date Date, key Int32, value String) Engine=MergeTree ORDER BY key PARTITION by date")
+    # 0. Insert data on two replicas
+    node_1.query("INSERT INTO test SELECT * FROM numbers(100)")
 
-    node1.query("INSERT INTO test SELECT toDate('2019-10-01'), number, toString(number) FROM numbers(100)")
+    check_data([node_1, node_2], detached_parts=[])
 
-    assert node1.query("SELECT COUNT() FROM test WHERE key % 10 == 0") == "10\n"
+    # 1. Detach the first three partition on the replicas
 
-    node1.query("ALTER TABLE test DETACH PARTITION '2019-10-01'")
+    # This part will be fetched from other replicas as it would be missing in the detached/ folder
+    node_1.query("ALTER TABLE test DETACH PARTITION '0_0_0_0'")
+    # This part will be fetched from other replicas as the checksums won't match (we'll manually break the data).
+    node_1.query("ALTER TABLE test DETACH PARTITION '1_0_0_0'")
+    # This part will be copied locally and attached without fetch
+    node_1.query("ALTER TABLE test DETACH PARTITION '2_0_0_0'")
 
-    assert node1.query("SELECT COUNT() FROM test WHERE key % 10 == 0") == "0\n"
-    assert node1.query("SELECT COUNT() FROM test") == "0\n"
+    check_data([node_1, node_2], detached_parts=[0, 1, 2])
 
-    # Break the network in the partition manager
-    # The data is not removed from detached/ so it's ok
+    # 2. Create the third replica
+    fill_node(node_3)
 
-    # to be sure output not empty
-    node1.exec_in_container(
-        ['bash', '-c', 'find /var/lib/clickhouse/data/default/test/detached -name "checksums.txt" | grep -e ".*" '],
-        privileged=True, user='root')
+    # 3. Attach the first partition and check if it has been fetched correctly
+    node_3.query("ALTER TABLE test ATTACH PARTITION '0_0_0_0'")
+    check_data([node_1, node_2, node_3], detached_parts=[1, 2])
 
-    node1.exec_in_container(
-        ['bash', '-c', 'find /var/lib/clickhouse/data/default/test/detached -name "checksums.txt" -delete'],
-        privileged=True, user='root')
+    # 4. Fetch the second partition to the third replica, break the data to corrupt the checksums,
+    # attach it and check if it also was fetched correctly.
+    node_3.query("ALTER TABLE test FETCH PARTITION '1_0_0_0' FROM '/clickhouse/tables/test'")
+    corrupt_part_data_on_disk(node_3, 'test', '1_0_0_0', is_detached=True)
+    node_3.query("ALTER TABLE test ATTACH PARTITION '1_0_0_0'")
 
-    node1.query("ALTER TABLE test ATTACH PARTITION '2019-10-01'")
+    check_data([node_1, node_2, node_3], detached_parts=[2])
 
-    assert node1.query("SELECT COUNT() FROM test WHERE key % 10 == 0") == "10\n"
-    assert node1.query("SELECT COUNT() FROM test") == "100\n"
+    # 5. Fetch the third partition to the third replica, break the network as so the replica won't be able to
+    # download the data, attach the partition (and check it has been attached from the local data)
+    node_3.query("ALTER TABLE test FETCH PARTITION '2_0_0_0' FROM '/clickhouse/tables/test'")
+
+    with PartitionManager() as pm:
+        pm.partition_instances(node_1, node_3)
+        pm.partition_instances(node_2, node_3)
+
+        node_3.query("ALTER TABLE test ATTACH PARTITION '2_0_0_0'")
+
+    check_data([node_1, node_2, node_3], detached_parts=[])

tests/integration/test_broken_part_during_merge/test.py

@@ -3,6 +3,7 @@ import pytest
 from helpers.cluster import ClickHouseCluster
 from multiprocessing.dummy import Pool
 from helpers.network import PartitionManager
+from helpers.corrupt_part_data_on_disk import corrupt_part_data_on_disk
 import time
 
 cluster = ClickHouseCluster(__file__)
@@ -25,13 +26,6 @@ def started_cluster():
     finally:
         cluster.shutdown()
 
-def corrupt_data_part_on_disk(node, table, part_name):
-    part_path = node.query(
-        "SELECT path FROM system.parts WHERE table = '{}' and name = '{}'".format(table, part_name)).strip()
-    node.exec_in_container(['bash', '-c',
-                            'cd {p} && ls *.bin | head -n 1 | xargs -I{{}} sh -c \'echo "1" >> $1\' -- {{}}'.format(
-                                p=part_path)], privileged=True)
-
 
 def test_merge_and_part_corruption(started_cluster):
     node1.query("SYSTEM STOP REPLICATION QUEUES replicated_mt")
@@ -43,7 +37,7 @@ def test_merge_and_part_corruption(started_cluster):
     # Need to corrupt "border part" (left or right). If we will corrupt something in the middle
     # clickhouse will not consider merge as broken, because we have parts with the same min and max
     # block numbers.
-    corrupt_data_part_on_disk(node1, 'replicated_mt', 'all_3_3_0')
+    corrupt_part_data_on_disk(node1, 'replicated_mt', 'all_3_3_0')
 
     with Pool(1) as p:
         def optimize_with_delay(x):