Add replication test

Author: Ngalstyan4

ci/scripts/build-linux.sh

@@ -53,7 +53,7 @@ function install_platform_specific_dependencies() {
     popd
 
     # dependencies of update tests
-    sudo pip install GitPython
+    sudo pip install GitPython testgres
     apt install -y ruby-full
     gem install bundler
 

ci/scripts/run-tests-linux.sh

@@ -53,6 +53,7 @@ function run_db_tests(){
     make test && \
     make test-parallel && \
     make test-client && \
+    python3 ../scripts/test_wal.py && \
     run_pgvector_tests && \
     stop_current_postgres && \
     if [[ "$ENABLE_COVERAGE" == "1" ]]

scripts/test_wal.py

@@ -0,0 +1,51 @@
+import testgres
+import os
+
+VECTOR_QUERY = "SELECT * FROM small_world WHERE b = FALSE order by v <-> '{1,0,0}' LIMIT 3;"
+
+with testgres.get_new_node() as primary:
+
+    # run inidb
+    primary.init()
+
+    primary.append_conf('enable_seqscan = off')
+
+    primary.start()
+
+    primary.execute('CREATE EXTENSION lantern')
+    # testgres safe_psql does not support specifying cwd, so we have to change the cwd of the current
+    # script to make sure relative paths in the target sql file work in testgres
+    os.chdir('../test/sql')
+    primary.safe_psql(filename='hnsw_delete.sql')
+    # create a backup
+    with primary.backup() as backup:
+
+        # create and start a new replica
+        replica = backup.spawn_replica('replica').start()
+
+        # catch up with master node
+        replica.catchup()
+
+        # make sure we are using the index
+        assert 'Index Scan using small_world_v_idx on small_world' in str(primary.safe_psql(f"EXPLAIN {VECTOR_QUERY}"))
+        assert 'Index Scan using small_world_v_idx on small_world' in str(replica.safe_psql(f"EXPLAIN {VECTOR_QUERY}"))
+
+        res = replica.execute(VECTOR_QUERY)
+        assert res[0][2] == [1.0, 0.0, 0.0]
+        # take only boolean columns
+        assert [i[1] for i in res] == [False]
+
+        # Now, let's delete data on primary and see how it propagates to replica
+        primary.execute("INSERT INTO small_world (id, b, v) VALUES (42, FALSE, '{42,42,42}'), (43, FALSE, '{42,42,42}'), (44, FALSE, '{42,42,42}');")
+
+        res = replica.execute(VECTOR_QUERY)
+        # changes have not propagated yet
+        assert res[0][2] == [1.0, 0.0, 0.0]
+        assert [i[1] for i in res] == [False]
+        replica.catchup()
+        res = replica.execute(VECTOR_QUERY)
+        assert res[0][2] == [1.0, 0.0, 0.0]
+        assert [i[1] for i in res] == [False, False, False], 'failed %s' % res
+
+print("WAL tests completed successfully!")
+