1 files changed, 56 insertions, 6 deletions

diff --git a/storage/src/tests/distributor/mergeoperationtest.cpp b/storage/src/tests/distributor/mergeoperationtest.cpp
index 65ee5254193..54bd06c98e0 100644
--- a/storage/src/tests/distributor/mergeoperationtest.cpp
+++ b/storage/src/tests/distributor/mergeoperationtest.cpp
@@ -1,5 +1,5 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-#include <tests/common/dummystoragelink.h>
+
 #include <tests/distributor/distributor_stripe_test_util.h>
 #include <vespa/document/test/make_bucket_space.h>
 #include <vespa/document/test/make_document_bucket.h>
@@ -12,6 +12,7 @@
 #include <vespa/vdslib/distribution/distribution.h>
 #include <vespa/vespalib/gtest/gtest.h>
 #include <vespa/vespalib/text/stringtokenizer.h>
+#include <charconv>
 
 using document::test::makeDocumentBucket;
 using document::test::makeBucketSpace;
@@ -37,6 +38,7 @@ struct MergeOperationTest : Test, DistributorStripeTestUtil {
     }
 
     std::shared_ptr<MergeOperation> setup_minimal_merge_op();
+    std::shared_ptr<MergeOperation> setup_simple_merge_op(const std::vector<uint16_t>& nodes);
     std::shared_ptr<MergeOperation> setup_simple_merge_op();
     void assert_simple_merge_bucket_command();
     void assert_simple_delete_bucket_command();
@@ -47,13 +49,13 @@ std::shared_ptr<MergeOperation>
 MergeOperationTest::setup_minimal_merge_op()
 {
     document::BucketId bucket_id(16, 1);
-    auto op = std::make_shared<MergeOperation>(BucketAndNodes(makeDocumentBucket(bucket_id), toVector<uint16_t>(0, 1, 2)));
+    auto op = std::make_shared<MergeOperation>(BucketAndNodes(makeDocumentBucket(bucket_id), {0, 1, 2}));
     op->setIdealStateManager(&getIdealStateManager());
     return op;
 }
 
 std::shared_ptr<MergeOperation> 
-MergeOperationTest::setup_simple_merge_op()
+MergeOperationTest::setup_simple_merge_op(const std::vector<uint16_t>& nodes)
 {
     getClock().setAbsoluteTimeInSeconds(10);
 
@@ -64,12 +66,18 @@ MergeOperationTest::setup_simple_merge_op()
 
     enable_cluster_state("distributor:1 storage:3");
 
-    auto op = std::make_shared<MergeOperation>(BucketAndNodes(makeDocumentBucket(document::BucketId(16, 1)), toVector<uint16_t>(0, 1, 2)));
+    auto op = std::make_shared<MergeOperation>(BucketAndNodes(makeDocumentBucket(document::BucketId(16, 1)), nodes));
     op->setIdealStateManager(&getIdealStateManager());
     op->start(_sender, framework::MilliSecTime(0));
     return op;
 }
 
+std::shared_ptr<MergeOperation>
+MergeOperationTest::setup_simple_merge_op()
+{
+    return setup_simple_merge_op({0, 1, 2});
+}
+
 void
 MergeOperationTest::assert_simple_merge_bucket_command()
 {
@@ -150,8 +158,10 @@ std::string getNodeList(std::string state, uint32_t redundancy, std::string exis
             num.erase(pos);
             trusted = true;
         }
-        bucketDB[i] = BucketCopy(0, atoi(num.c_str()),
-                                 api::BucketInfo(1, 2, 3));
+        uint16_t node;
+        [[maybe_unused]] auto [ptr, ec] = std::from_chars(num.data(), num.data() + num.size(), node);
+        assert(ec == std::errc{});
+        bucketDB[i] = BucketCopy(0, node, api::BucketInfo(1, 2, 3));
         bucketDB[i].setTrusted(trusted);
     }
     std::vector<MergeMetaData> nodes(st.size());
@@ -553,4 +563,44 @@ TEST_F(MergeOperationTest, on_throttled_updates_metrics)
     EXPECT_EQ(1, metrics->throttled.getValue());
 }
 
+TEST_F(MergeOperationTest, unordered_merges_only_sent_iff_config_enabled_and_all_nodes_support_feature) {
+    setup_stripe(Redundancy(4), NodeCount(4), "distributor:1 storage:4");
+    NodeSupportedFeatures with_unordered;
+    with_unordered.unordered_merge_chaining = true;
+
+    set_node_supported_features(1, with_unordered);
+    set_node_supported_features(2, with_unordered);
+
+    auto config = make_config();
+    config->set_use_unordered_merge_chaining(true);
+    configure_stripe(std::move(config));
+
+    // Only nodes {1, 2} support unordered merging; merges should be ordered (sent to lowest index node 1).
+    setup_simple_merge_op({1, 2, 3}); // Note: these will be re-ordered in ideal state order internally
+    ASSERT_EQ("MergeBucketCommand(BucketId(0x4000000000000001), to time 10000000, "
+              "cluster state version: 0, nodes: [2, 1, 3], chain: [], "
+              "reasons to start: ) => 1",
+              _sender.getLastCommand(true));
+
+    // All involved nodes support unordered merging; merges should be unordered (sent to ideal node 2)
+    setup_simple_merge_op({1, 2});
+    ASSERT_EQ("MergeBucketCommand(BucketId(0x4000000000000001), to time 10000001, "
+              "cluster state version: 0, nodes: [2, 1], chain: [] (unordered forwarding), "
+              "reasons to start: ) => 2",
+              _sender.getLastCommand(true));
+
+    _sender.clear();
+
+    config = make_config();
+    config->set_use_unordered_merge_chaining(false);
+    configure_stripe(std::move(config));
+
+    // If config is not enabled, should send ordered even if nodes support the feature.
+    setup_simple_merge_op({2, 1});
+    ASSERT_EQ("MergeBucketCommand(BucketId(0x4000000000000001), to time 10000002, "
+              "cluster state version: 0, nodes: [2, 1], chain: [], "
+              "reasons to start: ) => 1",
+              _sender.getLastCommand(true));
+}
+
 } // storage::distributor