Move portions of search::memoryindex::test::OrderedFieldIndexInserter to

search::memoryindex::test::OrderedFieldIndexInserterBackend.

12 files changed, 301 insertions, 179 deletions

diff --git a/searchlib/src/tests/memoryindex/document_inverter/document_inverter_test.cpp b/searchlib/src/tests/memoryindex/document_inverter/document_inverter_test.cpp
index bf9bbf1007a..dec21c64456 100644
--- a/searchlib/src/tests/memoryindex/document_inverter/document_inverter_test.cpp
+++ b/searchlib/src/tests/memoryindex/document_inverter/document_inverter_test.cpp
@@ -9,7 +9,9 @@
 #include <vespa/searchlib/memoryindex/i_field_index_collection.h>
 #include <vespa/searchlib/memoryindex/word_store.h>
 #include <vespa/searchlib/test/memoryindex/mock_field_index_collection.h>
-#include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h>
+#include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h>
+#include <vespa/vespalib/util/gate.h>
+#include <vespa/vespalib/util/destructor_callbacks.h>
 #include <vespa/vespalib/util/sequencedtaskexecutor.h>
 
 #include <vespa/vespalib/gtest/gtest.h>
@@ -99,7 +101,7 @@ struct DocumentInverterTest : public ::testing::Test {
     std::unique_ptr<ISequencedTaskExecutor> _pushThreads;
     WordStore                       _word_store;
     FieldIndexRemover               _remover;
-    test::OrderedFieldIndexInserter _inserter;
+    test::OrderedFieldIndexInserterBackend _inserter_backend;
     FieldLengthCalculator           _calculator;
     test::MockFieldIndexCollection  _fic;
     DocumentInverterContext         _inv_context;
@@ -117,27 +119,22 @@ struct DocumentInverterTest : public ::testing::Test {
     DocumentInverterTest()
         : _schema(makeSchema()),
           _b(_schema),
-          _invertThreads(SequencedTaskExecutor::create(invert_executor, 2)),
-          _pushThreads(SequencedTaskExecutor::create(push_executor, 2)),
+          _invertThreads(SequencedTaskExecutor::create(invert_executor, 1)),
+          _pushThreads(SequencedTaskExecutor::create(push_executor, 1)),
           _word_store(),
           _remover(_word_store),
-          _inserter(),
+          _inserter_backend(),
           _calculator(),
-          _fic(_remover, _inserter, _calculator),
+          _fic(_remover, _inserter_backend, _calculator),
           _inv_context(_schema, *_invertThreads, *_pushThreads, _fic),
           _inv(_inv_context)
     {
     }
 
     void pushDocuments() {
-        _invertThreads->sync_all();
-        uint32_t fieldId = 0;
-        for (auto &inverter : _inv.getInverters()) {
-            _inserter.setFieldId(fieldId);
-            inverter->pushDocuments();
-            ++fieldId;
-        }
-        _pushThreads->sync_all();
+        vespalib::Gate gate;
+        _inv.pushDocuments(std::make_shared<vespalib::GateCallback>(gate));
+        gate.await();
     }
 };
 
@@ -149,7 +146,7 @@ TEST_F(DocumentInverterTest, require_that_fresh_insert_works)
               "w=b,a=10,"
               "w=c,a=10,"
               "w=d,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(DocumentInverterTest, require_that_multiple_docs_work)
@@ -164,7 +161,7 @@ TEST_F(DocumentInverterTest, require_that_multiple_docs_work)
               "w=f,a=11,"
               "f=1,w=a,a=11,"
               "w=g,a=11",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(DocumentInverterTest, require_that_remove_works)
@@ -179,7 +176,7 @@ TEST_F(DocumentInverterTest, require_that_remove_works)
               "w=b,r=10,r=11,"
               "f=1,w=a,r=10,"
               "f=2,w=c,r=12",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(DocumentInverterTest, require_that_reput_works)
@@ -193,7 +190,7 @@ TEST_F(DocumentInverterTest, require_that_reput_works)
               "w=f,a=10,"
               "f=1,w=a,a=10,"
               "w=g,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(DocumentInverterTest, require_that_abort_pending_doc_works)
@@ -214,7 +211,7 @@ TEST_F(DocumentInverterTest, require_that_abort_pending_doc_works)
               "w=f,a=11,"
               "f=1,w=a,a=11,"
               "w=g,a=11",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 
     _inv.invertDocument(10, *doc10);
     _inv.invertDocument(11, *doc11);
@@ -223,7 +220,7 @@ TEST_F(DocumentInverterTest, require_that_abort_pending_doc_works)
     _inv.invertDocument(14, *doc14);
     _inv.removeDocument(11);
     _inv.removeDocument(13);
-    _inserter.reset();
+    _inserter_backend.reset();
     pushDocuments();
     EXPECT_EQ("f=0,w=a,a=10,"
               "w=b,a=10,"
@@ -233,7 +230,7 @@ TEST_F(DocumentInverterTest, require_that_abort_pending_doc_works)
               "w=doc14,a=14,"
               "w=h,a=12,"
               "w=j,a=14",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 
     _inv.invertDocument(10, *doc10);
     _inv.invertDocument(11, *doc11);
@@ -244,13 +241,13 @@ TEST_F(DocumentInverterTest, require_that_abort_pending_doc_works)
     _inv.removeDocument(12);
     _inv.removeDocument(13);
     _inv.removeDocument(14);
-    _inserter.reset();
+    _inserter_backend.reset();
     pushDocuments();
     EXPECT_EQ("f=0,w=a,a=10,"
               "w=b,a=10,"
               "w=c,a=10,"
               "w=d,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(DocumentInverterTest, require_that_mix_of_add_and_remove_works)
@@ -266,7 +263,7 @@ TEST_F(DocumentInverterTest, require_that_mix_of_add_and_remove_works)
               "w=c,r=9,a=10,"
               "w=d,r=10,a=10,"
               "w=z,r=12",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(DocumentInverterTest, require_that_empty_document_can_be_inverted)
@@ -274,7 +271,7 @@ TEST_F(DocumentInverterTest, require_that_empty_document_can_be_inverted)
     _inv.invertDocument(15, *makeDoc15(_b));
     pushDocuments();
     EXPECT_EQ("",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 }
diff --git a/searchlib/src/tests/memoryindex/document_inverter_collection/document_inverter_collection_test.cpp b/searchlib/src/tests/memoryindex/document_inverter_collection/document_inverter_collection_test.cpp
index a6d675d05dc..ef08a6fd0e1 100644
--- a/searchlib/src/tests/memoryindex/document_inverter_collection/document_inverter_collection_test.cpp
+++ b/searchlib/src/tests/memoryindex/document_inverter_collection/document_inverter_collection_test.cpp
@@ -9,7 +9,7 @@
 #include <vespa/searchlib/memoryindex/i_field_index_collection.h>
 #include <vespa/searchlib/memoryindex/word_store.h>
 #include <vespa/searchlib/test/memoryindex/mock_field_index_collection.h>
-#include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h>
+#include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h>
 #include <vespa/vespalib/util/retain_guard.h>
 #include <vespa/vespalib/util/sequencedtaskexecutor.h>
 #include <thread>
@@ -35,7 +35,7 @@ struct DocumentInverterCollectionTest : public ::testing::Test {
     std::unique_ptr<ISequencedTaskExecutor> _pushThreads;
     WordStore                       _word_store;
     FieldIndexRemover               _remover;
-    test::OrderedFieldIndexInserter _inserter;
+    test::OrderedFieldIndexInserterBackend _inserter_backend;
     FieldLengthCalculator           _calculator;
     test::MockFieldIndexCollection  _fic;
     DocumentInverterContext         _inv_context;
@@ -47,9 +47,9 @@ struct DocumentInverterCollectionTest : public ::testing::Test {
           _pushThreads(SequencedTaskExecutor::create(push_executor, 4)),
           _word_store(),
           _remover(_word_store),
-          _inserter(),
+          _inserter_backend(),
           _calculator(),
-          _fic(_remover, _inserter, _calculator),
+          _fic(_remover, _inserter_backend, _calculator),
           _inv_context(_schema, *_invertThreads, *_pushThreads, _fic),
           _inv_collection(_inv_context, 10)
     {
diff --git a/searchlib/src/tests/memoryindex/field_inverter/field_inverter_test.cpp b/searchlib/src/tests/memoryindex/field_inverter/field_inverter_test.cpp
index 9b718052dd0..ed049a82c42 100644
--- a/searchlib/src/tests/memoryindex/field_inverter/field_inverter_test.cpp
+++ b/searchlib/src/tests/memoryindex/field_inverter/field_inverter_test.cpp
@@ -7,6 +7,7 @@
 #include <vespa/searchlib/memoryindex/field_inverter.h>
 #include <vespa/searchlib/memoryindex/word_store.h>
 #include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h>
+#include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h>
 #include <vespa/vespalib/objects/nbostream.h>
 #include <vespa/vespalib/gtest/gtest.h>
 
@@ -136,8 +137,9 @@ struct FieldInverterTest : public ::testing::Test {
     DocBuilder _b;
     WordStore                       _word_store;
     FieldIndexRemover               _remover;
-    test::OrderedFieldIndexInserter _inserter;
+    test::OrderedFieldIndexInserterBackend _inserter_backend;
     std::vector<std::unique_ptr<FieldLengthCalculator>> _calculators;
+    std::vector<std::unique_ptr<IOrderedFieldIndexInserter>> _inserters;
     std::vector<std::unique_ptr<FieldInverter> > _inverters;
 
     static Schema makeSchema() {
@@ -154,17 +156,19 @@ struct FieldInverterTest : public ::testing::Test {
           _b(_schema),
           _word_store(),
           _remover(_word_store),
-          _inserter(),
+          _inserter_backend(),
           _calculators(),
+          _inserters(),
           _inverters()
     {
         for (uint32_t fieldId = 0; fieldId < _schema.getNumIndexFields();
              ++fieldId) {
             _calculators.emplace_back(std::make_unique<FieldLengthCalculator>());
+            _inserters.emplace_back(std::make_unique<test::OrderedFieldIndexInserter>(_inserter_backend, fieldId));
             _inverters.push_back(std::make_unique<FieldInverter>(_schema,
                                                                  fieldId,
                                                                  _remover,
-                                                                 _inserter,
+                                                                 *_inserters.back(),
                                                                  *_calculators.back()));
         }
     }
@@ -180,11 +184,8 @@ struct FieldInverterTest : public ::testing::Test {
     }
 
     void pushDocuments() {
-        uint32_t fieldId = 0;
         for (auto &inverter : _inverters) {
-            _inserter.setFieldId(fieldId);
             inverter->pushDocuments();
-            ++fieldId;
         }
     }
 
@@ -210,7 +211,7 @@ TEST_F(FieldInverterTest, require_that_fresh_insert_works)
               "w=b,a=10,"
               "w=c,a=10,"
               "w=d,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_multiple_docs_work)
@@ -225,7 +226,7 @@ TEST_F(FieldInverterTest, require_that_multiple_docs_work)
               "w=f,a=11,"
               "f=1,w=a,a=11,"
               "w=g,a=11",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_remove_works)
@@ -240,7 +241,7 @@ TEST_F(FieldInverterTest, require_that_remove_works)
               "w=b,r=10,r=11,"
               "f=1,w=a,r=10,"
               "f=2,w=c,r=12",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_reput_works)
@@ -254,7 +255,7 @@ TEST_F(FieldInverterTest, require_that_reput_works)
               "w=f,a=10,"
               "f=1,w=a,a=10,"
               "w=g,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_abort_pending_doc_works)
@@ -275,7 +276,7 @@ TEST_F(FieldInverterTest, require_that_abort_pending_doc_works)
               "w=f,a=11,"
               "f=1,w=a,a=11,"
               "w=g,a=11",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 
     invertDocument(10, *doc10);
     invertDocument(11, *doc11);
@@ -284,7 +285,7 @@ TEST_F(FieldInverterTest, require_that_abort_pending_doc_works)
     invertDocument(14, *doc14);
     removeDocument(11);
     removeDocument(13);
-    _inserter.reset();
+    _inserter_backend.reset();
     pushDocuments();
     EXPECT_EQ("f=0,w=a,a=10,"
               "w=b,a=10,"
@@ -294,7 +295,7 @@ TEST_F(FieldInverterTest, require_that_abort_pending_doc_works)
               "w=doc14,a=14,"
               "w=h,a=12,"
               "w=j,a=14",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 
     invertDocument(10, *doc10);
     invertDocument(11, *doc11);
@@ -305,13 +306,13 @@ TEST_F(FieldInverterTest, require_that_abort_pending_doc_works)
     removeDocument(12);
     removeDocument(13);
     removeDocument(14);
-    _inserter.reset();
+    _inserter_backend.reset();
     pushDocuments();
     EXPECT_EQ("f=0,w=a,a=10,"
               "w=b,a=10,"
               "w=c,a=10,"
               "w=d,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_mix_of_add_and_remove_works)
@@ -327,7 +328,7 @@ TEST_F(FieldInverterTest, require_that_mix_of_add_and_remove_works)
               "w=c,r=9,a=10,"
               "w=d,r=10,a=10,"
               "w=z,r=12",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_empty_document_can_be_inverted)
@@ -335,13 +336,13 @@ TEST_F(FieldInverterTest, require_that_empty_document_can_be_inverted)
     invertDocument(15, *makeDoc15(_b));
     pushDocuments();
     EXPECT_EQ("",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_multiple_words_at_same_position_works)
 {
     invertDocument(16, *makeDoc16(_b));
-    _inserter.setVerbose();
+    _inserter_backend.setVerbose();
     pushDocuments();
     EXPECT_EQ("f=0,"
               "w=altbaz,a=16(e=0,w=1,l=5[2]),"
@@ -351,14 +352,14 @@ TEST_F(FieldInverterTest, require_that_multiple_words_at_same_position_works)
               "w=foo,a=16(e=0,w=1,l=5[0]),"
               "w=y,a=16(e=0,w=1,l=5[3]),"
               "w=z,a=16(e=0,w=1,l=5[4])",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_interleaved_features_are_calculated)
 {
     invertDocument(17, *makeDoc17(_b));
-    _inserter.setVerbose();
-    _inserter.set_show_interleaved_features();
+    _inserter_backend.setVerbose();
+    _inserter_backend.set_show_interleaved_features();
     pushDocuments();
     EXPECT_EQ("f=1,"
               "w=bar0,a=17(fl=2,occs=1,e=0,w=1,l=2[1]),"
@@ -369,7 +370,7 @@ TEST_F(FieldInverterTest, require_that_interleaved_features_are_calculated)
               "f=3,"
               "w=bar2,a=17(fl=3,occs=2,e=0,w=3,l=2[1],e=1,w=4,l=1[0]),"
               "w=foo2,a=17(fl=3,occs=1,e=0,w=3,l=2[0])",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_average_field_length_is_calculated)
@@ -397,7 +398,7 @@ TEST_F(FieldInverterTest, require_that_word_with_NUL_byte_is_truncated)
               "w=before,a=1,"
               "w=corrupt,a=1,"
               "w=z,a=1",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(FieldInverterTest, require_that_word_with_NUL_byte_is_dropped_when_truncated_to_zero_length)
@@ -408,7 +409,7 @@ TEST_F(FieldInverterTest, require_that_word_with_NUL_byte_is_dropped_when_trunca
               "w=after,a=1,"
               "w=before,a=1,"
               "w=z,a=1",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 }
diff --git a/searchlib/src/tests/memoryindex/url_field_inverter/url_field_inverter_test.cpp b/searchlib/src/tests/memoryindex/url_field_inverter/url_field_inverter_test.cpp
index 5f73b9b8282..969f483eef6 100644
--- a/searchlib/src/tests/memoryindex/url_field_inverter/url_field_inverter_test.cpp
+++ b/searchlib/src/tests/memoryindex/url_field_inverter/url_field_inverter_test.cpp
@@ -8,6 +8,7 @@
 #include <vespa/searchlib/memoryindex/url_field_inverter.h>
 #include <vespa/searchlib/memoryindex/word_store.h>
 #include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h>
+#include <vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h>
 #include <vespa/vespalib/gtest/gtest.h>
 
 namespace search {
@@ -181,8 +182,9 @@ struct UrlFieldInverterTest : public ::testing::Test {
     DocBuilder _b;
     WordStore                       _word_store;
     FieldIndexRemover               _remover;
-    test::OrderedFieldIndexInserter _inserter;
+    test::OrderedFieldIndexInserterBackend _inserter_backend;
     FieldLengthCalculator           _calculator;
+    std::vector<std::unique_ptr<IOrderedFieldIndexInserter>> _inserters;
     std::vector<std::unique_ptr<FieldInverter> > _inverters;
     std::unique_ptr<UrlFieldInverter> _urlInverter;
     index::SchemaIndexFields _schemaIndexFields;
@@ -198,8 +200,9 @@ struct UrlFieldInverterTest : public ::testing::Test {
           _b(_schema),
           _word_store(),
           _remover(_word_store),
-          _inserter(),
+          _inserter_backend(),
           _calculator(),
+          _inserters(),
           _inverters(),
           _urlInverter(),
           _schemaIndexFields()
@@ -207,10 +210,11 @@ struct UrlFieldInverterTest : public ::testing::Test {
         _schemaIndexFields.setup(_schema);
         for (uint32_t fieldId = 0; fieldId < _schema.getNumIndexFields();
              ++fieldId) {
+            _inserters.emplace_back(std::make_unique<test::OrderedFieldIndexInserter>(_inserter_backend, fieldId));
             _inverters.push_back(std::make_unique<FieldInverter>(_schema,
                                                                  fieldId,
                                                                  _remover,
-                                                                 _inserter,
+                                                                 *_inserters.back(),
                                                                  _calculator));
         }
         index::UriField &urlField =
@@ -234,11 +238,8 @@ struct UrlFieldInverterTest : public ::testing::Test {
     }
 
     void pushDocuments() {
-        uint32_t fieldId = 0;
         for (auto &inverter : _inverters) {
-            _inserter.setFieldId(fieldId);
             inverter->pushDocuments();
-            ++fieldId;
         }
     }
 
@@ -297,7 +298,7 @@ TEST_F(SingleInverterTest, require_that_single_url_field_works)
               "w=com,a=10,"
               "w=example,a=10,"
               "w=www,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(ArrayInverterTest, require_that_array_url_field_works)
@@ -340,7 +341,7 @@ TEST_F(ArrayInverterTest, require_that_array_url_field_works)
               "w=example,a=10,"
               "w=flickr,a=10,"
               "w=www,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(WeightedSetInverterTest, require_that_weighted_set_field_works)
@@ -385,7 +386,7 @@ TEST_F(WeightedSetInverterTest, require_that_weighted_set_field_works)
               "w=example,a=10,"
               "w=flickr,a=10,"
               "w=www,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(SingleInverterTest, require_that_annotated_single_url_field_works)
@@ -425,7 +426,7 @@ TEST_F(SingleInverterTest, require_that_annotated_single_url_field_works)
               "w=com,a=10,"
               "w=example,a=10,"
               "w=www,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(ArrayInverterTest, require_that_annotated_array_url_field_works)
@@ -470,13 +471,13 @@ TEST_F(ArrayInverterTest, require_that_annotated_array_url_field_works)
               "w=example,a=10,"
               "w=flickr,a=10,"
               "w=www,a=10",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(WeightedSetInverterTest, require_that_annotated_weighted_set_field_works)
 {
     enableAnnotations();
-    _inserter.setVerbose();
+    _inserter_backend.setVerbose();
     invertDocument(10, *makeDoc10WeightedSet(_b));
     pushDocuments();
     EXPECT_EQ("f=0,"
@@ -518,14 +519,14 @@ TEST_F(WeightedSetInverterTest, require_that_annotated_weighted_set_field_works)
               "w=example,a=10(e=0,w=4,l=5[2]),"
               "w=flickr,a=10(e=1,w=7,l=5[2]),"
               "w=www,a=10(e=0,w=4,l=5[1],e=1,w=7,l=5[1])",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(SingleInverterTest, require_that_empty_single_field_works)
 {
     invertDocument(10, *makeDoc10Empty(_b));
     pushDocuments();
-    EXPECT_EQ("", _inserter.toStr());
+    EXPECT_EQ("", _inserter_backend.toStr());
 }
 
 TEST_F(ArrayInverterTest, require_that_empty_array_field_works)
@@ -533,14 +534,14 @@ TEST_F(ArrayInverterTest, require_that_empty_array_field_works)
     invertDocument(10, *makeDoc10Empty(_b));
     pushDocuments();
     EXPECT_EQ("",
-              _inserter.toStr());
+              _inserter_backend.toStr());
 }
 
 TEST_F(WeightedSetInverterTest, require_that_empty_weighted_set_field_works)
 {
     invertDocument(10, *makeDoc10Empty(_b));
     pushDocuments();
-    EXPECT_EQ("", _inserter.toStr());
+    EXPECT_EQ("", _inserter_backend.toStr());
 }
 
 TEST_F(SingleInverterTest, require_that_annotated_empty_single_field_works)
@@ -548,7 +549,7 @@ TEST_F(SingleInverterTest, require_that_annotated_empty_single_field_works)
     enableAnnotations();
     invertDocument(10, *makeDoc10Empty(_b));
     pushDocuments();
-    EXPECT_EQ("", _inserter.toStr());
+    EXPECT_EQ("", _inserter_backend.toStr());
 }
 
 TEST_F(ArrayInverterTest, require_that_annotated_empty_array_field_works)
@@ -556,7 +557,7 @@ TEST_F(ArrayInverterTest, require_that_annotated_empty_array_field_works)
     enableAnnotations();
     invertDocument(10, *makeDoc10Empty(_b));
     pushDocuments();
-    EXPECT_EQ("", _inserter.toStr());
+    EXPECT_EQ("", _inserter_backend.toStr());
 }
 
 TEST_F(WeightedSetInverterTest, require_that_annotated_empty_weighted_set_field_works)
@@ -564,7 +565,7 @@ TEST_F(WeightedSetInverterTest, require_that_annotated_empty_weighted_set_field_
     enableAnnotations();
     invertDocument(10, *makeDoc10Empty(_b));
     pushDocuments();
-    EXPECT_EQ("", _inserter.toStr());
+    EXPECT_EQ("", _inserter_backend.toStr());
 }
 
 }
diff --git a/searchlib/src/vespa/searchlib/memoryindex/document_inverter.h b/searchlib/src/vespa/searchlib/memoryindex/document_inverter.h
index f69d482f565..dc4fba5d6b0 100644
--- a/searchlib/src/vespa/searchlib/memoryindex/document_inverter.h
+++ b/searchlib/src/vespa/searchlib/memoryindex/document_inverter.h
@@ -92,8 +92,6 @@ public:
         return _inverters[fieldId].get();
     }
 
-    const std::vector<std::unique_ptr<FieldInverter> > & getInverters() const { return _inverters; }
-
     uint32_t getNumFields() const { return _inverters.size(); }
     void wait_for_zero_ref_count() { _ref_count.waitForZeroRefCount(); }
     bool has_zero_ref_count() { return _ref_count.has_zero_ref_count(); }
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/CMakeLists.txt b/searchlib/src/vespa/searchlib/test/memoryindex/CMakeLists.txt
index c7cc6d77ede..ff948166033 100644
--- a/searchlib/src/vespa/searchlib/test/memoryindex/CMakeLists.txt
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/CMakeLists.txt
@@ -2,5 +2,7 @@
 vespa_add_library(searchlib_searchlib_test_memoryindex
     SOURCES
     mock_field_index_collection.cpp
+    ordered_field_index_inserter.cpp
+    ordered_field_index_inserter_backend.cpp
     DEPENDS
 )
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.cpp b/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.cpp
index 1392a92853d..a98e20deba5 100644
--- a/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.cpp
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.cpp
@@ -6,10 +6,10 @@
 namespace search::memoryindex::test {
 
 MockFieldIndexCollection::MockFieldIndexCollection(FieldIndexRemover& remover,
-                                                   OrderedFieldIndexInserter& inserter,
+                                                   OrderedFieldIndexInserterBackend& inserter_backend,
                                                    index::FieldLengthCalculator& calculator)
     : _remover(remover),
-      _inserter(inserter),
+      _inserter_backend(inserter_backend),
       _calculator(calculator)
 {
 }
@@ -23,9 +23,16 @@ MockFieldIndexCollection::get_remover(uint32_t)
 }
 
 IOrderedFieldIndexInserter&
-MockFieldIndexCollection::get_inserter(uint32_t)
+MockFieldIndexCollection::get_inserter(uint32_t field_id)
 {
-    return _inserter;
+    if (_inserters.size() <= field_id) {
+        _inserters.resize(field_id + 1);
+    }
+    auto& inserter = _inserters[field_id];
+    if (!inserter) {
+        inserter = std::make_unique<OrderedFieldIndexInserter>(_inserter_backend, field_id);
+    }
+    return *inserter;
 }
 
 index::FieldLengthCalculator&
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.h b/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.h
index 0dd7127f0ae..c7f2d364c5b 100644
--- a/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.h
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/mock_field_index_collection.h
@@ -3,29 +3,32 @@
 #pragma once
 
 #include <vespa/searchlib/memoryindex/i_field_index_collection.h>
+#include <memory>
+#include <vector>
 
 namespace search::index { class FieldLengthCalculator; }
 namespace search::memoryindex { class FieldIndexRemover; }
 
 namespace search::memoryindex::test {
 
-class OrderedFieldIndexInserter;
+class OrderedFieldIndexInserterBackend;
 
 /*
  * Mockup of field index collection used by unit tests.
  */
 class MockFieldIndexCollection : public IFieldIndexCollection {
     FieldIndexRemover&            _remover;
-    OrderedFieldIndexInserter&    _inserter;
+    OrderedFieldIndexInserterBackend& _inserter_backend;
     index::FieldLengthCalculator& _calculator;
+    std::vector<std::unique_ptr<IOrderedFieldIndexInserter>> _inserters;
 
 public:
     MockFieldIndexCollection(FieldIndexRemover& remover,
-                             OrderedFieldIndexInserter& inserter,
+                             OrderedFieldIndexInserterBackend& inserter_backend,
                              index::FieldLengthCalculator& calculator);
     ~MockFieldIndexCollection() override;
     FieldIndexRemover& get_remover(uint32_t) override;
-    IOrderedFieldIndexInserter& get_inserter(uint32_t) override;
+    IOrderedFieldIndexInserter& get_inserter(uint32_t field_id) override;
     index::FieldLengthCalculator& get_calculator(uint32_t) override;
 };
 
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.cpp b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.cpp
new file mode 100644
index 00000000000..6dbd434e20a
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.cpp
@@ -0,0 +1,57 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "ordered_field_index_inserter.h"
+#include "ordered_field_index_inserter_backend.h"
+
+namespace search::memoryindex::test {
+
+OrderedFieldIndexInserter::OrderedFieldIndexInserter(OrderedFieldIndexInserterBackend& backend, uint32_t field_id)
+    : _backend(backend),
+      _field_id(field_id)
+{
+}
+
+OrderedFieldIndexInserter::~OrderedFieldIndexInserter() = default;
+
+void
+OrderedFieldIndexInserter::setNextWord(const vespalib::stringref word)
+{
+    _backend.setNextWord(word);
+}
+
+void
+OrderedFieldIndexInserter::add(uint32_t docId, const index::DocIdAndFeatures &features)
+{
+    _backend.add(docId, features);
+}
+
+vespalib::datastore::EntryRef
+OrderedFieldIndexInserter::getWordRef() const
+{
+    return vespalib::datastore::EntryRef();
+}
+
+void
+OrderedFieldIndexInserter::remove(uint32_t docId)
+{
+    _backend.remove(docId);
+}
+
+void
+OrderedFieldIndexInserter::flush()
+{
+}
+
+void
+OrderedFieldIndexInserter::commit()
+{
+}
+
+void
+OrderedFieldIndexInserter::rewind()
+{
+    _backend.rewind(_field_id);
+}
+
+}
+
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h
index de7023499a1..20b8e58fa60 100644
--- a/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter.h
@@ -2,109 +2,29 @@
 
 #pragma once
 
-#include <vespa/searchlib/index/docidandfeatures.h>
 #include <vespa/searchlib/memoryindex/i_ordered_field_index_inserter.h>
-#include <sstream>
 
 namespace search::memoryindex::test {
 
-class OrderedFieldIndexInserter : public IOrderedFieldIndexInserter {
-    std::stringstream _ss;
-    bool _first;
-    bool _verbose;
-    bool _show_interleaved_features;
-    uint32_t _fieldId;
-
-    void addComma() {
-        if (!_first) {
-            _ss << ",";
-        } else {
-            _first = false;
-        }
-    }
+class OrderedFieldIndexInserterBackend;
 
+/*
+ * Test version of ordered field index inserter that uses a backend to create
+ * a string representation used to validate correct use of ordered field index inserter.
+ */
+class OrderedFieldIndexInserter : public IOrderedFieldIndexInserter {
+    OrderedFieldIndexInserterBackend& _backend;
+    uint32_t _field_id;
 public:
-    OrderedFieldIndexInserter()
-        : _ss(),
-          _first(true),
-          _verbose(false),
-          _show_interleaved_features(false),
-          _fieldId(0)
-    {
-    }
-
-    virtual void setNextWord(const vespalib::stringref word) override {
-        addComma();
-        _ss << "w=" << word;
-    }
-
-    void setFieldId(uint32_t fieldId) {
-        _fieldId = fieldId;
-    }
-
-    virtual void add(uint32_t docId,
-                     const index::DocIdAndFeatures &features) override {
-        (void) features;
-        addComma();
-        _ss << "a=" << docId;
-        if (_verbose) {
-            _ss << "(";
-            auto wpi = features.word_positions().begin();
-            bool firstElement = true;
-            if (_show_interleaved_features) {
-                _ss << "fl=" << features.field_length() <<
-                    ",occs=" << features.num_occs();
-                firstElement = false;
-            }
-            for (auto &el : features.elements()) {
-                if (!firstElement) {
-                    _ss << ",";
-                }
-                firstElement = false;
-                _ss << "e=" << el.getElementId() << ",w=" <<
-                    el.getWeight() <<  ",l=" <<
-                    el.getElementLen() << "[";
-                bool firstWordPos = true;
-                for (uint32_t i = 0; i < el.getNumOccs(); ++i) {
-                    if (!firstWordPos) {
-                        _ss << ",";
-                    }
-                    firstWordPos = false;
-                    _ss << wpi->getWordPos();
-                    ++wpi;
-                }
-                _ss << "]";
-            }
-            _ss << ")";
-        }
-    }
-
-    virtual vespalib::datastore::EntryRef getWordRef() const override { return vespalib::datastore::EntryRef(); }
-
-    virtual void remove(uint32_t docId) override {
-        addComma();
-        _ss << "r=" << docId;
-    }
-
-    virtual void flush() override { }
-    virtual void commit() override { }
-    virtual void rewind() override {
-        addComma();
-        _ss << "f=" << _fieldId;
-    }
-
-    std::string toStr() const {
-        return _ss.str();
-    }
-
-    void reset() {
-        _ss.str("");
-        _first = true;
-        _verbose = false;
-    }
-
-    void setVerbose() { _verbose = true; }
-    void set_show_interleaved_features() { _show_interleaved_features = true; }
+    OrderedFieldIndexInserter(OrderedFieldIndexInserterBackend& backend, uint32_t field_id);
+    ~OrderedFieldIndexInserter() override;
+    void setNextWord(const vespalib::stringref word) override;
+    void add(uint32_t docId, const index::DocIdAndFeatures &features) override;
+    vespalib::datastore::EntryRef getWordRef() const override;
+    void remove(uint32_t docId) override;
+    void flush() override;
+    void commit() override;
+    void rewind() override;
 };
 
 }
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.cpp b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.cpp
new file mode 100644
index 00000000000..ef35ffa4bdc
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.cpp
@@ -0,0 +1,101 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "ordered_field_index_inserter_backend.h"
+#include <vespa/searchlib/index/docidandfeatures.h>
+
+namespace search::memoryindex::test {
+
+OrderedFieldIndexInserterBackend::OrderedFieldIndexInserterBackend()
+    : _ss(),
+      _first(true),
+      _verbose(false),
+      _show_interleaved_features(false)
+{
+}
+
+OrderedFieldIndexInserterBackend::~OrderedFieldIndexInserterBackend() = default;
+
+void
+OrderedFieldIndexInserterBackend::addComma()
+{
+    if (!_first) {
+        _ss << ",";
+    } else {
+        _first = false;
+    }
+}
+
+void
+OrderedFieldIndexInserterBackend::setNextWord(const vespalib::stringref word)
+{
+    addComma();
+    _ss << "w=" << word;
+}
+
+void
+OrderedFieldIndexInserterBackend::add(uint32_t docId, const index::DocIdAndFeatures &features)
+{
+    (void) features;
+    addComma();
+    _ss << "a=" << docId;
+    if (_verbose) {
+        _ss << "(";
+        auto wpi = features.word_positions().begin();
+        bool firstElement = true;
+        if (_show_interleaved_features) {
+            _ss << "fl=" << features.field_length() <<
+                ",occs=" << features.num_occs();
+            firstElement = false;
+        }
+        for (auto &el : features.elements()) {
+            if (!firstElement) {
+                _ss << ",";
+            }
+            firstElement = false;
+            _ss << "e=" << el.getElementId() << ",w=" <<
+                el.getWeight() <<  ",l=" <<
+                el.getElementLen() << "[";
+            bool firstWordPos = true;
+            for (uint32_t i = 0; i < el.getNumOccs(); ++i) {
+                if (!firstWordPos) {
+                    _ss << ",";
+                }
+                firstWordPos = false;
+                _ss << wpi->getWordPos();
+                ++wpi;
+            }
+            _ss << "]";
+        }
+        _ss << ")";
+    }
+}
+
+void
+OrderedFieldIndexInserterBackend::remove(uint32_t docId)
+{
+    addComma();
+    _ss << "r=" << docId;
+}
+
+void
+OrderedFieldIndexInserterBackend::rewind(uint32_t field_id)
+{
+    addComma();
+    _ss << "f=" << field_id;
+}
+
+std::string
+OrderedFieldIndexInserterBackend::toStr() const
+{
+    return _ss.str();
+}
+
+void
+OrderedFieldIndexInserterBackend::reset()
+{
+    _ss.str("");
+    _first = true;
+    _verbose = false;
+}
+
+}
diff --git a/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h
new file mode 100644
index 00000000000..e81b6db5c36
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/test/memoryindex/ordered_field_index_inserter_backend.h
@@ -0,0 +1,35 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include <vespa/vespalib/stllike/string.h>
+#include <sstream>
+
+namespace search::index { class DocIdAndFeatures; }
+
+namespace search::memoryindex::test {
+
+/*
+ * Backend for test version of ordered field index inserter that creates
+ * a string representation used to validate correct use of ordered field index inserter.
+ */
+class OrderedFieldIndexInserterBackend {
+    std::stringstream _ss;
+    bool _first;
+    bool _verbose;
+    bool _show_interleaved_features;
+    void addComma();
+public:
+    OrderedFieldIndexInserterBackend();
+    ~OrderedFieldIndexInserterBackend();
+    void setNextWord(const vespalib::stringref word);
+    void add(uint32_t docId, const index::DocIdAndFeatures &features);
+    void remove(uint32_t docId);
+    void rewind(uint32_t field_id);
+    std::string toStr() const;
+    void reset();
+    void setVerbose() { _verbose = true; }
+    void set_show_interleaved_features() { _show_interleaved_features = true; }
+};
+
+}