also check graph symmetry

2 files changed, 7 insertions, 1 deletions

diff --git a/searchlib/src/tests/tensor/hnsw_index/stress_hnsw_mt.cpp b/searchlib/src/tests/tensor/hnsw_index/stress_hnsw_mt.cpp
index ea443cfe252..fa6f760a33f 100644
--- a/searchlib/src/tests/tensor/hnsw_index/stress_hnsw_mt.cpp
+++ b/searchlib/src/tests/tensor/hnsw_index/stress_hnsw_mt.cpp
@@ -12,7 +12,6 @@
 #include <vespa/vespalib/data/slime/slime.h>
 #include <vespa/vespalib/util/threadstackexecutor.h>
 #include <vespa/vespalib/util/blockingthreadstackexecutor.h>
-#include <vespa/vespalib/util/gate.h>
 #include <vespa/vespalib/util/lambdatask.h>
 
 #include <vector>
@@ -352,6 +351,10 @@ TEST_F(Stressor, stress)
         gen_operation();
         if (i % 1000 == 0) {
             fprintf(stderr, "generating operations %d / %d\n", i, NUM_OPS);
+            auto r = write_thread.execute(vespalib::makeLambdaTask([&]() {
+                        EXPECT_TRUE(index->check_link_symmetry());
+            }));
+            EXPECT_EQ(bool(r), false);
         }
     }
     fprintf(stderr, "waiting for queued operations...\n");
@@ -359,6 +362,7 @@ TEST_F(Stressor, stress)
     write_thread.sync();
     in_progress->invalidateCachedCount();
     EXPECT_EQ(in_progress->countTrueBits(), 0);
+    EXPECT_TRUE(index->check_link_symmetry());
     fprintf(stderr, "all done.\n");
 }
 
diff --git a/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp b/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp
index d78c7a64c89..c9474eaf483 100644
--- a/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp
+++ b/searchlib/src/vespa/searchlib/tensor/hnsw_index.cpp
@@ -620,6 +620,8 @@ HnswIndex::check_link_symmetry() const
                     auto neighbor_links = _graph.get_link_array(neighbor_docid, level);
                     if (! has_link_to(neighbor_links, docid)) {
                         all_sym = false;
+                        LOG(warning, "check_link_symmetry: docid %zu links to %u on level %u, but no backlink",
+                            docid, neighbor_docid, level);
                     }
                 }
                 ++level;