[fix](inverted index) create empty idx file when creating a index on variant-type column (#50937)

be/src/olap/rowset/segment_v2/inverted_index_file_writer.cpp

@@ -23,6 +23,7 @@
 #include <filesystem>
 
 #include "common/status.h"
+#include "io/fs/stream_sink_file_writer.h"
 #include "olap/rowset/segment_v2/inverted_index_desc.h"
 #include "olap/rowset/segment_v2/inverted_index_fs_directory.h"
 #include "olap/rowset/segment_v2/inverted_index_reader.h"
@@ -124,6 +125,10 @@ Status InvertedIndexFileWriter::close() {
     DCHECK(!_closed) << debug_string();
     _closed = true;
     if (_indices_dirs.empty()) {
+        // An empty file must still be created even if there are no indexes to write
+        if (dynamic_cast<io::StreamSinkFileWriter*>(_idx_v2_writer.get()) != nullptr) {
+            return _idx_v2_writer->close();
+        }
         return Status::OK();
     }
     DBUG_EXECUTE_IF("inverted_index_storage_format_must_be_v2", {

be/src/runtime/load_stream_writer.cpp

@@ -174,7 +174,8 @@ Status LoadStreamWriter::close_writer(uint32_t segid, FileType file_type) {
     LOG(INFO) << "file " << segid << " path " << file_writer->path().native() << "closed, written "
               << file_writer->bytes_appended() << " bytes"
               << ", file type is " << file_type;
-    if (file_writer->bytes_appended() == 0) {
+    // ‌Allow the index file to be empty when creating an index on a variant-type column.
+    if (file_writer->bytes_appended() == 0 && file_type != FileType::INVERTED_INDEX_FILE) {
         return Status::Corruption("file {} closed with 0 bytes, file type is {}",
                                   file_writer->path().native(), file_type);
     }

be/test/olap/rowset/segment_v2/inverted_index/empty_index_file_test.cpp

@@ -0,0 +1,92 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include <brpc/channel.h>
+#include <brpc/server.h>
+
+#include "gtest/gtest_pred_impl.h"
+#include "io/fs/stream_sink_file_writer.h"
+#include "olap/olap_common.h"
+#include "olap/rowset/segment_v2/inverted_index_file_writer.h"
+#include "vec/sink/load_stream_stub.h"
+
+namespace doris {
+
+constexpr int64_t LOAD_ID_LO = 1;
+constexpr int64_t LOAD_ID_HI = 2;
+constexpr int64_t NUM_STREAM = 3;
+constexpr static std::string_view tmp_dir = "./ut_dir/tmp";
+class EmptyIndexFileTest : public testing::Test {
+    class MockStreamStub : public LoadStreamStub {
+    public:
+        MockStreamStub(PUniqueId load_id, int64_t src_id)
+                : LoadStreamStub(load_id, src_id, std::make_shared<IndexToTabletSchema>(),
+                                 std::make_shared<IndexToEnableMoW>()) {};
+
+        virtual ~MockStreamStub() = default;
+
+        // APPEND_DATA
+        virtual Status append_data(int64_t partition_id, int64_t index_id, int64_t tablet_id,
+                                   int64_t segment_id, uint64_t offset, std::span<const Slice> data,
+                                   bool segment_eos = false,
+                                   FileType file_type = FileType::SEGMENT_FILE) override {
+            EXPECT_TRUE(segment_eos);
+            return Status::OK();
+        }
+    };
+
+public:
+    EmptyIndexFileTest() = default;
+    ~EmptyIndexFileTest() = default;
+
+protected:
+    virtual void SetUp() {
+        _load_id.set_hi(LOAD_ID_HI);
+        _load_id.set_lo(LOAD_ID_LO);
+        for (int src_id = 0; src_id < NUM_STREAM; src_id++) {
+            _streams.emplace_back(new MockStreamStub(_load_id, src_id));
+        }
+        EXPECT_TRUE(io::global_local_filesystem()->delete_directory(tmp_dir).ok());
+        EXPECT_TRUE(io::global_local_filesystem()->create_directory(tmp_dir).ok());
+        std::vector<StorePath> paths;
+        paths.emplace_back(std::string(tmp_dir), 1024000000);
+        auto tmp_file_dirs = std::make_unique<segment_v2::TmpFileDirs>(paths);
+        EXPECT_TRUE(tmp_file_dirs->init().ok());
+        ExecEnv::GetInstance()->set_tmp_file_dir(std::move(tmp_file_dirs));
+    }
+
+    virtual void TearDown() {
+        EXPECT_TRUE(io::global_local_filesystem()->delete_directory(tmp_dir).ok());
+    }
+
+    PUniqueId _load_id;
+    std::vector<std::shared_ptr<LoadStreamStub>> _streams;
+};
+
+TEST_F(EmptyIndexFileTest, test_empty_index_file) {
+    io::FileWriterPtr file_writer = std::make_unique<io::StreamSinkFileWriter>(_streams);
+    auto fs = io::global_local_filesystem();
+    std::string index_path = "/tmp/empty_index_file_test";
+    std::string rowset_id = "1234567890";
+    int64_t seg_id = 1234567890;
+    auto index_file_writer = std::make_unique<segment_v2::InvertedIndexFileWriter>(
+            fs, index_path, rowset_id, seg_id, InvertedIndexStorageFormatPB::V2,
+            std::move(file_writer));
+    EXPECT_TRUE(index_file_writer->close().ok());
+}
+
+} // namespace doris

regression-test/data/inverted_index_p0/test_variant_empty_index_file.out

@@ -0,0 +1,4 @@
+-- This file is automatically generated. You should know what you did if you want to edit this
+-- !sql --
+1	"abcd"
+

regression-test/suites/inverted_index_p0/test_variant_empty_index_file.groovy

@@ -0,0 +1,57 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+suite("test_variant_empty_index_file", "p0") {
+    def tableName = "test_variant_empty_index_file"
+    sql """ drop table if exists ${tableName} """
+    // create table
+    sql """
+        CREATE TABLE IF NOT EXISTS ${tableName}
+        (   
+            `id`   bigint NOT NULL,
+            `v`    variant NULL,
+            INDEX  v_idx (`v`) USING INVERTED
+        ) DUPLICATE KEY(`id`)
+        DISTRIBUTED BY HASH (`id`) BUCKETS 1
+        PROPERTIES (
+        "replication_allocation" = "tag.location.default: 1",
+        "inverted_index_storage_format" = "v2",
+        "disable_auto_compaction" = "true"
+        );
+    """
+
+    sql """ set enable_memtable_on_sink_node = true """
+    sql """ insert into ${tableName} values (1, 'abcd') """
+
+    def tablets = sql_return_maparray """ show tablets from ${tableName}; """
+
+    def backendId_to_backendIP = [:]
+    def backendId_to_backendHttpPort = [:]
+    getBackendIpHttpPort(backendId_to_backendIP, backendId_to_backendHttpPort);
+
+    String tablet_id = tablets[0].TabletId
+    String backend_id = tablets[0].BackendId
+    String ip = backendId_to_backendIP.get(backend_id)
+    String port = backendId_to_backendHttpPort.get(backend_id)
+    if (!isCloudMode()) {
+        def (code, out, err) = http_client("GET", String.format("http://%s:%s/api/show_nested_index_file?tablet_id=%s", ip, port, tablet_id))
+        logger.info("Run show_nested_index_file_on_tablet: code=" + code + ", out=" + out + ", err=" + err)
+        assertEquals("E-6002", parseJson(out.trim()).status)
+    }
+
+    qt_sql """ select * from ${tableName} where v match 'abcd'"""
+}