Creating the document metastore read guard is expensive and is not necessary to do for every imported attribute.

We do it once per metastore and cache it in the ImportedAttributeContext.
It would be even better if we could drop support for the default makeReadGuard(bool).
Then we would also avoid copying the shared_ptr.

1 files changed, 7 insertions, 1 deletions

diff --git a/searchlib/src/vespa/searchlib/attribute/imported_attribute_vector.cpp b/searchlib/src/vespa/searchlib/attribute/imported_attribute_vector.cpp
index 1ae2b6ee749..6218f3d72b2 100644
--- a/searchlib/src/vespa/searchlib/attribute/imported_attribute_vector.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/imported_attribute_vector.cpp
@@ -43,7 +43,13 @@ ImportedAttributeVector::~ImportedAttributeVector() = default;
 std::unique_ptr<AttributeReadGuard>
 ImportedAttributeVector::makeReadGuard(bool stableEnumGuard) const
 {
-    return std::make_unique<ImportedAttributeVectorReadGuard>(*this, stableEnumGuard);
+    return makeReadGuard(_target_document_meta_store->getReadGuard(), stableEnumGuard);
+}
+
+std::unique_ptr<AttributeReadGuard>
+ImportedAttributeVector::makeReadGuard(std::shared_ptr<MetaStoreReadGuard> targetMetaStoreReadGuard,  bool stableEnumGuard) const
+{
+    return std::make_unique<ImportedAttributeVectorReadGuard>(std::move(targetMetaStoreReadGuard), *this, stableEnumGuard);
 }
 
 void ImportedAttributeVector::clearSearchCache() {