diff --git a/core/src/db/SSDBImpl.cpp b/core/src/db/SSDBImpl.cpp
index 87d0c86ffa..5566244b31 100644
--- a/core/src/db/SSDBImpl.cpp
+++ b/core/src/db/SSDBImpl.cpp
@@ -12,6 +12,7 @@
 #include "db/SSDBImpl.h"
 #include "cache/CpuCacheMgr.h"
 #include "db/IDGenerator.h"
+#include "db/merge/MergeManagerFactory.h"
 #include "db/snapshot/CompoundOperations.h"
 #include "db/snapshot/ResourceHelper.h"
 #include "db/snapshot/ResourceTypes.h"
@@ -51,6 +52,7 @@ static const Status SHUTDOWN_ERROR = Status(DB_ERROR, "Milvus server is shutdown
 SSDBImpl::SSDBImpl(const DBOptions& options)
     : options_(options), initialized_(false), merge_thread_pool_(1, 1), index_thread_pool_(1, 1) {
     mem_mgr_ = MemManagerFactory::SSBuild(options_);
+    merge_mgr_ptr_ = MergeManagerFactory::SSBuild(options_);
 
     if (options_.wal_enable_) {
         wal::MXLogConfiguration mxlog_config;
diff --git a/core/src/db/merge/MergeManagerFactory.cpp b/core/src/db/merge/MergeManagerFactory.cpp
index 4f15281e16..aa3186c999 100644
--- a/core/src/db/merge/MergeManagerFactory.cpp
+++ b/core/src/db/merge/MergeManagerFactory.cpp
@@ -11,6 +11,7 @@
 
 #include "db/merge/MergeManagerFactory.h"
 #include "db/merge/MergeManagerImpl.h"
+#include "db/merge/SSMergeManagerImpl.h"
 #include "utils/Exception.h"
 #include "utils/Log.h"
 
@@ -22,5 +23,10 @@ MergeManagerFactory::Build(const meta::MetaPtr& meta_ptr, const DBOptions& optio
     return std::make_shared<MergeManagerImpl>(meta_ptr, options, MergeStrategyType::LAYERED);
 }
 
+MergeManagerPtr
+MergeManagerFactory::SSBuild(const DBOptions& options) {
+    return std::make_shared<SSMergeManagerImpl>(options, MergeStrategyType::SIMPLE);
+}
+
 }  // namespace engine
 }  // namespace milvus
diff --git a/core/src/db/merge/MergeManagerFactory.h b/core/src/db/merge/MergeManagerFactory.h
index 533a321161..b7a072aa14 100644
--- a/core/src/db/merge/MergeManagerFactory.h
+++ b/core/src/db/merge/MergeManagerFactory.h
@@ -23,6 +23,9 @@ class MergeManagerFactory {
  public:
     static MergeManagerPtr
     Build(const meta::MetaPtr& meta_ptr, const DBOptions& options);
+
+    static MergeManagerPtr
+    SSBuild(const DBOptions& options);
 };
 
 }  // namespace engine
diff --git a/core/src/db/merge/SSMergeManagerImpl.cpp b/core/src/db/merge/SSMergeManagerImpl.cpp
new file mode 100644
index 0000000000..f46a70761f
--- /dev/null
+++ b/core/src/db/merge/SSMergeManagerImpl.cpp
@@ -0,0 +1,98 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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 "db/merge/SSMergeManagerImpl.h"
+#include "db/merge/SSMergeSimpleStrategy.h"
+#include "db/merge/SSMergeTask.h"
+#include "db/snapshot/Snapshots.h"
+#include "utils/Exception.h"
+#include "utils/Log.h"
+
+#include <map>
+
+namespace milvus {
+namespace engine {
+
+SSMergeManagerImpl::SSMergeManagerImpl(const DBOptions& options, MergeStrategyType type)
+    : options_(options), strategy_type_(type) {
+    UseStrategy(type);
+}
+
+Status
+SSMergeManagerImpl::UseStrategy(MergeStrategyType type) {
+    switch (type) {
+        case MergeStrategyType::SIMPLE: {
+            strategy_ = std::make_shared<SSMergeSimpleStrategy>();
+            break;
+        }
+        case MergeStrategyType::LAYERED:
+        case MergeStrategyType::ADAPTIVE:
+        default: {
+            std::string msg = "Unsupported merge strategy type: " + std::to_string((int32_t)type);
+            LOG_ENGINE_ERROR_ << msg;
+            throw Exception(DB_ERROR, msg);
+        }
+    }
+    strategy_type_ = type;
+
+    return Status::OK();
+}
+
+Status
+SSMergeManagerImpl::MergeFiles(const std::string& collection_name) {
+    if (strategy_ == nullptr) {
+        std::string msg = "No merge strategy specified";
+        LOG_ENGINE_ERROR_ << msg;
+        return Status(DB_ERROR, msg);
+    }
+
+    int64_t row_count_per_segment = DEFAULT_ROW_COUNT_PER_SEGMENT;
+    while (true) {
+        snapshot::ScopedSnapshotT latest_ss;
+        STATUS_CHECK(snapshot::Snapshots::GetInstance().GetSnapshot(latest_ss, collection_name));
+
+        Partition2SegmentsMap part2seg;
+        auto& segments = latest_ss->GetResources<snapshot::Segment>();
+        for (auto& kv : segments) {
+            auto segment_commit = latest_ss->GetSegmentCommitBySegmentId(kv.second->GetID());
+            part2seg[kv.second->GetPartitionId()].push_back(kv.second->GetID());
+        }
+
+        Partition2SegmentsMap::iterator it;
+        for (it = part2seg.begin(); it != part2seg.end();) {
+            if (it->second.size() <= 1) {
+                part2seg.erase(it++);
+            }
+        }
+
+        if (part2seg.empty()) {
+            break;
+        }
+
+        SegmentGroups segment_groups;
+        auto status = strategy_->RegroupSegments(latest_ss, part2seg, segment_groups);
+        if (!status.ok()) {
+            LOG_ENGINE_ERROR_ << "Failed to regroup segments for: " << collection_name
+                              << ", continue to merge all files into one";
+            return status;
+        }
+
+        for (auto& segments : segment_groups) {
+            SSMergeTask task(options_, latest_ss, segments);
+            task.Execute();
+        }
+    }
+
+    return Status::OK();
+}
+
+}  // namespace engine
+}  // namespace milvus
diff --git a/core/src/db/merge/SSMergeManagerImpl.h b/core/src/db/merge/SSMergeManagerImpl.h
new file mode 100644
index 0000000000..bd900b044f
--- /dev/null
+++ b/core/src/db/merge/SSMergeManagerImpl.h
@@ -0,0 +1,53 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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.
+
+#pragma once
+
+#include <ctime>
+#include <map>
+#include <memory>
+#include <mutex>
+#include <set>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "db/merge/MergeManager.h"
+#include "db/merge/SSMergeStrategy.h"
+#include "utils/Status.h"
+
+namespace milvus {
+namespace engine {
+
+class SSMergeManagerImpl : public MergeManager {
+ public:
+    SSMergeManagerImpl(const DBOptions& options, MergeStrategyType type);
+
+    MergeStrategyType
+    Strategy() const override {
+        return strategy_type_;
+    }
+
+    Status
+    UseStrategy(MergeStrategyType type) override;
+
+    Status
+    MergeFiles(const std::string& collection_name) override;
+
+ private:
+    DBOptions options_;
+
+    MergeStrategyType strategy_type_ = MergeStrategyType::SIMPLE;
+    SSMergeStrategyPtr strategy_;
+};  // MergeManagerImpl
+
+}  // namespace engine
+}  // namespace milvus
diff --git a/core/src/db/merge/SSMergeSimpleStrategy.cpp b/core/src/db/merge/SSMergeSimpleStrategy.cpp
new file mode 100644
index 0000000000..ff8f97f711
--- /dev/null
+++ b/core/src/db/merge/SSMergeSimpleStrategy.cpp
@@ -0,0 +1,58 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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 "db/merge/SSMergeSimpleStrategy.h"
+#include "db/snapshot/Snapshots.h"
+#include "utils/Log.h"
+
+namespace milvus {
+namespace engine {
+
+const char* ROW_COUNT_PER_SEGMENT = "row_count_per_segment";
+
+Status
+SSMergeSimpleStrategy::RegroupSegments(const snapshot::ScopedSnapshotT& ss, const Partition2SegmentsMap& part2segment,
+                                       SegmentGroups& groups) {
+    auto collection = ss->GetCollection();
+
+    int64_t row_count_per_segment = DEFAULT_ROW_COUNT_PER_SEGMENT;
+    const json params = collection->GetParams();
+    if (params.find(ROW_COUNT_PER_SEGMENT) != params.end()) {
+        row_count_per_segment = params[ROW_COUNT_PER_SEGMENT];
+    }
+
+    for (auto& kv : part2segment) {
+        snapshot::IDS_TYPE ids;
+        int64_t row_count_sum = 0;
+        for (auto& id : kv.second) {
+            auto segment_commit = ss->GetSegmentCommitBySegmentId(id);
+            if (segment_commit == nullptr) {
+                continue;  // maybe stale
+            }
+
+            ids.push_back(id);
+            row_count_sum += segment_commit->GetRowCount();
+            if (row_count_sum >= row_count_per_segment) {
+                if (ids.size() >= 2) {
+                    groups.push_back(ids);
+                }
+                ids.clear();
+                row_count_sum = 0;
+                continue;
+            }
+        }
+    }
+
+    return Status::OK();
+}
+
+}  // namespace engine
+}  // namespace milvus
diff --git a/core/src/db/merge/SSMergeSimpleStrategy.h b/core/src/db/merge/SSMergeSimpleStrategy.h
new file mode 100644
index 0000000000..217e46e44f
--- /dev/null
+++ b/core/src/db/merge/SSMergeSimpleStrategy.h
@@ -0,0 +1,31 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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.
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "db/merge/SSMergeStrategy.h"
+#include "utils/Status.h"
+
+namespace milvus {
+namespace engine {
+
+class SSMergeSimpleStrategy : public SSMergeStrategy {
+ public:
+    Status
+    RegroupSegments(const snapshot::ScopedSnapshotT& ss, const Partition2SegmentsMap& part2segment,
+                    SegmentGroups& groups) override;
+};  // MergeSimpleStrategy
+
+}  // namespace engine
+}  // namespace milvus
diff --git a/core/src/db/merge/SSMergeStrategy.h b/core/src/db/merge/SSMergeStrategy.h
new file mode 100644
index 0000000000..badadf7b73
--- /dev/null
+++ b/core/src/db/merge/SSMergeStrategy.h
@@ -0,0 +1,43 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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.
+
+#pragma once
+
+#include <map>
+#include <memory>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "db/Types.h"
+#include "db/snapshot/ResourceTypes.h"
+#include "db/snapshot/Snapshot.h"
+#include "utils/Status.h"
+
+namespace milvus {
+namespace engine {
+
+const int64_t DEFAULT_ROW_COUNT_PER_SEGMENT = 500000;
+
+using Partition2SegmentsMap = std::map<snapshot::ID_TYPE, snapshot::IDS_TYPE>;
+using SegmentGroups = std::vector<snapshot::IDS_TYPE>;
+
+class SSMergeStrategy {
+ public:
+    virtual Status
+    RegroupSegments(const snapshot::ScopedSnapshotT& ss, const Partition2SegmentsMap& part2segment,
+                    SegmentGroups& groups) = 0;
+};  // MergeStrategy
+
+using SSMergeStrategyPtr = std::shared_ptr<SSMergeStrategy>;
+
+}  // namespace engine
+}  // namespace milvus
diff --git a/core/src/db/merge/SSMergeTask.cpp b/core/src/db/merge/SSMergeTask.cpp
new file mode 100644
index 0000000000..6397fb7897
--- /dev/null
+++ b/core/src/db/merge/SSMergeTask.cpp
@@ -0,0 +1,76 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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 "db/merge/SSMergeTask.h"
+#include "db/Utils.h"
+#include "db/snapshot/CompoundOperations.h"
+#include "db/snapshot/Operations.h"
+#include "db/snapshot/Snapshots.h"
+#include "metrics/Metrics.h"
+#include "segment/SegmentReader.h"
+#include "segment/SegmentWriter.h"
+#include "utils/Log.h"
+
+#include <memory>
+#include <string>
+
+namespace milvus {
+namespace engine {
+
+SSMergeTask::SSMergeTask(const DBOptions& options, const snapshot::ScopedSnapshotT& ss,
+                         const snapshot::IDS_TYPE& segments)
+    : options_(options), snapshot_(ss), segments_(segments) {
+}
+
+Status
+SSMergeTask::Execute() {
+    if (segments_.size() <= 1) {
+        return Status::OK();
+    }
+
+    snapshot::OperationContext context;
+    for (auto& id : segments_) {
+        auto seg = snapshot_->GetResource<snapshot::Segment>(id);
+        if (!seg) {
+            return Status(DB_ERROR, "snapshot segment is null");
+        }
+
+        context.stale_segments.push_back(seg);
+        if (!context.prev_partition) {
+            snapshot::PartitionPtr partition = snapshot_->GetResource<snapshot::Partition>(seg->GetPartitionId());
+            context.prev_partition = partition;
+        }
+    }
+
+    auto op = std::make_shared<snapshot::MergeOperation>(context, snapshot_);
+    snapshot::SegmentPtr new_seg;
+    auto status = op->CommitNewSegment(new_seg);
+    if (!status.ok()) {
+        return status;
+    }
+
+    // TODO: merge each field, each field create a new SegmentFile
+    snapshot::SegmentFileContext sf_context;
+    sf_context.field_name = "vector";
+    sf_context.field_element_name = "ivfsq8";
+    sf_context.segment_id = 1;
+    sf_context.partition_id = 1;
+    sf_context.segment_id = new_seg->GetID();
+    snapshot::SegmentFilePtr seg_file;
+    status = op->CommitNewSegmentFile(sf_context, seg_file);
+
+    status = op->Push();
+
+    return status;
+}
+
+}  // namespace engine
+}  // namespace milvus
diff --git a/core/src/db/merge/SSMergeTask.h b/core/src/db/merge/SSMergeTask.h
new file mode 100644
index 0000000000..bfb22214cc
--- /dev/null
+++ b/core/src/db/merge/SSMergeTask.h
@@ -0,0 +1,39 @@
+// Copyright (C) 2019-2020 Zilliz. All rights reserved.
+//
+// Licensed 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.
+
+#pragma once
+
+#include <string>
+
+#include "db/merge/MergeManager.h"
+#include "db/meta/MetaTypes.h"
+#include "db/snapshot/ResourceTypes.h"
+#include "db/snapshot/Snapshot.h"
+#include "utils/Status.h"
+
+namespace milvus {
+namespace engine {
+
+class SSMergeTask {
+ public:
+    SSMergeTask(const DBOptions& options, const snapshot::ScopedSnapshotT& ss, const snapshot::IDS_TYPE& segments);
+
+    Status
+    Execute();
+
+ private:
+    DBOptions options_;
+    snapshot::ScopedSnapshotT snapshot_;
+    snapshot::IDS_TYPE segments_;
+};  // SSMergeTask
+
+}  // namespace engine
+}  // namespace milvus