Explain need for serializing late part of attribute manager initialization

1 files changed, 4 insertions, 0 deletions

diff --git a/searchcore/src/vespa/searchcore/proton/attribute/attribute_manager_initializer.cpp b/searchcore/src/vespa/searchcore/proton/attribute/attribute_manager_initializer.cpp
index 8fe8a36ec94..e9fdd8638c9 100644
--- a/searchcore/src/vespa/searchcore/proton/attribute/attribute_manager_initializer.cpp
+++ b/searchcore/src/vespa/searchcore/proton/attribute/attribute_manager_initializer.cpp
@@ -173,6 +173,10 @@ AttributeManagerInitializer::run()
 {
     std::promise<bool> promise;
     std::future<bool> future = promise.get_future();
+    /*
+     * Attribute manager and some its members (e.g. _attributeFieldWriter) assumes that work is performed
+     * by document db master thread and lacks locking to handle calls from multiple threads.
+     */
     _master.execute(std::make_unique<AttributeManagerInitializerTask>(std::move(promise),
                                                                       _configSerialNum,
                                                                       _documentMetaStore,