From 5964adef4936dcd9849a64126e8e100707ff4c5c Mon Sep 17 00:00:00 2001
From: XuPeng-SH <xupeng3112@163.com>
Date: Tue, 7 Jul 2020 19:38:30 +0800
Subject: [PATCH] (db/snapshot): Implement operation rollback (#2760)

* (db/snapshot): refactor Operations

Signed-off-by: peng.xu <peng.xu@zilliz.com>

* (db/snapshot): refactor Operations

Signed-off-by: peng.xu <peng.xu@zilliz.com>

* (db/snapshot): Add rollback for operations

Signed-off-by: peng.xu <peng.xu@zilliz.com>
---
 core/src/db/snapshot/EventExecutor.h |   6 +-
 core/src/db/snapshot/Operations.cpp  |  35 ++++--
 core/src/db/snapshot/Operations.h    |  36 ++++--
 core/src/db/snapshot/Resources.h     |  12 ++
 core/src/db/snapshot/Store.h         | 161 ++++-----------------------
 5 files changed, 86 insertions(+), 164 deletions(-)

diff --git a/core/src/db/snapshot/EventExecutor.h b/core/src/db/snapshot/EventExecutor.h
index f831c68a..f0acfbc6 100644
--- a/core/src/db/snapshot/EventExecutor.h
+++ b/core/src/db/snapshot/EventExecutor.h
@@ -70,13 +70,17 @@ class EventExecutor {
  private:
     void
     ThreadMain() {
+        Status status;
         while (true) {
             EventPtr evt = queue_.Take();
             if (evt == nullptr) {
                 break;
             }
             /* std::cout << std::this_thread::get_id() << " Dequeue Event " << std::endl; */
-            evt->Process();
+            status = evt->Process();
+            if (!status.ok()) {
+                std::cout << "EventExecutor Handle Event Error: " << status.ToString() << std::endl;
+            }
         }
     }
 
diff --git a/core/src/db/snapshot/Operations.cpp b/core/src/db/snapshot/Operations.cpp
index e47b3c07..27f104cf 100644
--- a/core/src/db/snapshot/Operations.cpp
+++ b/core/src/db/snapshot/Operations.cpp
@@ -12,6 +12,8 @@
 #include "db/snapshot/Operations.h"
 #include <chrono>
 #include <sstream>
+#include "db/snapshot/Event.h"
+#include "db/snapshot/EventExecutor.h"
 #include "db/snapshot/OperationExecutor.h"
 #include "db/snapshot/Snapshots.h"
 
@@ -100,6 +102,13 @@ Operations::Done(Store& store) {
             Snapshots::GetInstance().LoadSnapshot(store, context_.latest_ss,
                                                   context_.new_collection_commit->GetCollectionId(), ids_.back());
         }
+        /* if (!context_.latest_ss && context_.new_collection_commit) { */
+        /*     auto& holder = std::get<ConstPos(last_pos_)>(holders_); */
+        /*     if (holder.size() > 0) */
+        /*         Snapshots::GetInstance().LoadSnapshot(store, context_.latest_ss, */
+        /*                 context_.new_collection_commit->GetCollectionId(), holder.rbegin()->GetID()); */
+        /*     } */
+        /* } */
         std::cout << ToString() << std::endl;
     }
     finish_cond_.notify_all();
@@ -230,24 +239,28 @@ Operations::DoExecute(Store& store) {
 
 Status
 Operations::PostExecute(Store& store) {
-    return store.DoCommitOperation(*this);
+    return store.ApplyOperation(*this);
 }
 
-Status
-Operations::RollBack() {
-    // TODO: Implement here
-    // Spwarn a rollback operation or re-use this operation
-    return Status::OK();
+template <typename ResourceT>
+void
+ApplyRollBack(std::set<std::shared_ptr<ResourceT>>& steps_set) {
+    for (auto& res : steps_set) {
+        auto evt_ptr = std::make_shared<ResourceGCEvent<ResourceT>>(res);
+        EventExecutor::GetInstance().Submit(evt_ptr);
+        std::cout << "Rollback " << typeid(ResourceT).name() << ": " << res->GetID() << std::endl;
+    }
 }
 
-Status
-Operations::ApplyRollBack(Store& store) {
-    // TODO: Implement rollback to remove all resources in steps_
-    return Status::OK();
+void
+Operations::RollBack() {
+    std::apply([&](auto&... steps_set) { ((ApplyRollBack(steps_set)), ...); }, GetStepHolders());
 }
 
 Operations::~Operations() {
-    // TODO: Prefer to submit a rollback operation if status is not ok
+    if (!status_.ok()) {
+        RollBack();
+    }
 }
 
 }  // namespace snapshot
diff --git a/core/src/db/snapshot/Operations.h b/core/src/db/snapshot/Operations.h
index 18f65a1f..7ec39cf2 100644
--- a/core/src/db/snapshot/Operations.h
+++ b/core/src/db/snapshot/Operations.h
@@ -17,8 +17,10 @@
 #include <condition_variable>
 #include <memory>
 #include <mutex>
+#include <set>
 #include <string>
 #include <thread>
+#include <tuple>
 #include <vector>
 #include "Context.h"
 #include "db/snapshot/Snapshot.h"
@@ -30,8 +32,10 @@ namespace milvus {
 namespace engine {
 namespace snapshot {
 
-using StepsT = std::vector<std::any>;
 using CheckStaleFunc = std::function<Status(ScopedSnapshotT&)>;
+using StepsHolderT = std::tuple<CollectionCommit::SetT, Collection::SetT, SchemaCommit::SetT, FieldCommit::SetT,
+                                Field::SetT, FieldElement::SetT, PartitionCommit::SetT, Partition::SetT,
+                                SegmentCommit::SetT, Segment::SetT, SegmentFile::SetT>;
 
 enum OperationsType { Invalid, W_Leaf, O_Leaf, W_Compound, O_Compound };
 
@@ -71,9 +75,14 @@ class Operations : public std::enable_shared_from_this<Operations> {
         ids_.push_back(id);
     }
 
-    StepsT&
-    GetSteps() {
-        return steps_;
+    const size_t
+    GetPos() const {
+        return last_pos_;
+    }
+
+    StepsHolderT&
+    GetStepHolders() {
+        return holders_;
     }
 
     ID_TYPE
@@ -132,9 +141,6 @@ class Operations : public std::enable_shared_from_this<Operations> {
     virtual std::string
     ToString() const;
 
-    Status
-    RollBack();
-
     virtual Status
     OnSnapshotStale();
     virtual Status
@@ -158,12 +164,13 @@ class Operations : public std::enable_shared_from_this<Operations> {
     Status
     CheckPrevSnapshot() const;
 
-    Status
-    ApplyRollBack(Store&);
+    void
+    RollBack();
 
     OperationContext context_;
     ScopedSnapshotT prev_ss_;
-    StepsT steps_;
+    StepsHolderT holders_;
+    size_t last_pos_;
     std::vector<ID_TYPE> ids_;
     bool done_ = false;
     Status status_;
@@ -179,7 +186,10 @@ Operations::AddStep(const StepT& step, bool activate) {
     auto s = std::make_shared<StepT>(step);
     if (activate)
         s->Activate();
-    steps_.push_back(s);
+
+    last_pos_ = Index<typename StepT::SetT, StepsHolderT>::value;
+    auto& holder = std::get<Index<typename StepT::SetT, StepsHolderT>::value>(holders_);
+    holder.insert(s);
 }
 
 template <typename StepT>
@@ -189,7 +199,9 @@ Operations::AddStepWithLsn(const StepT& step, const LSN_TYPE& lsn, bool activate
     if (activate)
         s->Activate();
     s->SetLsn(lsn);
-    steps_.push_back(s);
+    last_pos_ = Index<typename StepT::SetT, StepsHolderT>::value;
+    auto& holder = std::get<Index<typename StepT::SetT, StepsHolderT>::value>(holders_);
+    holder.insert(s);
 }
 
 template <typename ResourceT>
diff --git a/core/src/db/snapshot/Resources.h b/core/src/db/snapshot/Resources.h
index 9ef67a42..7a97b867 100644
--- a/core/src/db/snapshot/Resources.h
+++ b/core/src/db/snapshot/Resources.h
@@ -15,6 +15,7 @@
 #include <map>
 #include <memory>
 #include <mutex>
+#include <set>
 #include <string>
 #include <thread>
 #include <utility>
@@ -354,6 +355,7 @@ class Collection : public BaseResource,
  public:
     using Ptr = std::shared_ptr<Collection>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<Collection>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "Collection";
@@ -380,6 +382,7 @@ class CollectionCommit : public BaseResource,
     static constexpr const char* Name = "CollectionCommit";
     using Ptr = std::shared_ptr<CollectionCommit>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<CollectionCommit>>;
     using VecT = std::vector<Ptr>;
     CollectionCommit(ID_TYPE collection_id, ID_TYPE schema_id, const MappingT& mappings = {}, SIZE_TYPE row_cnt = 0,
@@ -402,6 +405,7 @@ class Partition : public BaseResource,
  public:
     using Ptr = std::shared_ptr<Partition>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<Partition>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "Partition";
@@ -426,6 +430,7 @@ class PartitionCommit : public BaseResource,
  public:
     using Ptr = std::shared_ptr<PartitionCommit>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<PartitionCommit>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "PartitionCommit";
@@ -454,6 +459,7 @@ class Segment : public BaseResource,
  public:
     using Ptr = std::shared_ptr<Segment>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<Segment>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "Segment";
@@ -483,6 +489,7 @@ class SegmentCommit : public BaseResource,
  public:
     using Ptr = std::shared_ptr<SegmentCommit>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<SegmentCommit>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "SegmentCommit";
@@ -514,6 +521,7 @@ class SegmentFile : public BaseResource,
  public:
     using Ptr = std::shared_ptr<SegmentFile>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<SegmentFile>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "SegmentFile";
@@ -538,6 +546,7 @@ class SchemaCommit : public BaseResource,
  public:
     using Ptr = std::shared_ptr<SchemaCommit>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<SchemaCommit>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "SchemaCommit";
@@ -564,6 +573,7 @@ class Field : public BaseResource,
  public:
     using Ptr = std::shared_ptr<Field>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<Field>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "Field";
@@ -587,6 +597,7 @@ class FieldCommit : public BaseResource,
  public:
     using Ptr = std::shared_ptr<FieldCommit>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<FieldCommit>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "FieldCommit";
@@ -614,6 +625,7 @@ class FieldElement : public BaseResource,
  public:
     using Ptr = std::shared_ptr<FieldElement>;
     using MapT = std::map<ID_TYPE, Ptr>;
+    using SetT = std::set<Ptr>;
     using ScopedMapT = std::map<ID_TYPE, ScopedResource<FieldElement>>;
     using VecT = std::vector<Ptr>;
     static constexpr const char* Name = "FieldElement";
diff --git a/core/src/db/snapshot/Store.h b/core/src/db/snapshot/Store.h
index bc40556f..d96915a8 100644
--- a/core/src/db/snapshot/Store.h
+++ b/core/src/db/snapshot/Store.h
@@ -24,6 +24,7 @@
 #include <iostream>
 #include <map>
 #include <memory>
+#include <set>
 #include <shared_mutex>
 #include <sstream>
 #include <string>
@@ -53,52 +54,35 @@ class Store {
         return store;
     }
 
-    template <typename... ResourceT>
-    bool
-    DoCommit(ResourceT&&... resources) {
-        auto t = std::make_tuple(std::forward<ResourceT>(resources)...);
-        auto& t_size = std::tuple_size<decltype(t)>::value;
-        if (t_size == 0) {
-            return false;
-        }
-        StartTransaction();
-        std::apply([this](auto&&... resource) { ((std::cout << CommitResource(resource) << "\n"), ...); }, t);
-        FinishTransaction();
-        return true;
-    }
-
     template <typename OpT>
     Status
-    DoCommitOperation(OpT& op) {
-        for (auto& step_v : op.GetSteps()) {
-            auto id = ProcessOperationStep(step_v);
-            op.SetStepResult(id);
-        }
+    ApplyOperation(OpT& op) {
+        std::apply(
+            [&](auto&... steps_set) {
+                std::size_t n{0};
+                ((ApplyOpStep(op, n++, steps_set)), ...);
+            },
+            op.GetStepHolders());
         return Status::OK();
     }
 
-    template <typename OpT>
+    template <typename T, typename OpT>
     void
-    Apply(OpT& op) {
-        op.ApplyToStore(*this);
-    }
-
-    void
-    StartTransaction() {
+    ApplyOpStep(OpT& op, size_t pos, std::set<std::shared_ptr<T>>& steps_set) {
+        typename T::Ptr ret;
+        for (auto& res : steps_set) {
+            CreateResource<T>(T(*res), ret);
+            res->SetID(ret->GetID());
+        }
+        if (ret && (pos == op.GetPos())) {
+            op.SetStepResult(ret->GetID());
+        }
     }
 
+    template <typename OpT>
     void
-    FinishTransaction() {
-    }
-
-    template <typename ResourceT>
-    bool
-    CommitResource(ResourceT&& resource) {
-        std::cout << "Commit " << resource.Name << " " << resource.GetID() << std::endl;
-        auto res = CreateResource<typename std::remove_reference<ResourceT>::type>(std::move(resource));
-        if (!res)
-            return false;
-        return true;
+    Apply(OpT& op) {
+        op.ApplyToStore(*this);
     }
 
     template <typename ResourceT>
@@ -280,110 +264,7 @@ class Store {
     }
 
  private:
-    ID_TYPE
-    ProcessOperationStep(const std::any& step_v) {
-        if (const auto it = any_flush_vistors_.find(std::type_index(step_v.type())); it != any_flush_vistors_.cend()) {
-            return it->second(step_v);
-        } else {
-            std::cerr << "Unregisted step type " << std::quoted(step_v.type().name());
-            return 0;
-        }
-    }
-
-    template <class T, class F>
-    inline std::pair<const std::type_index, std::function<ID_TYPE(std::any const&)>>
-    to_any_visitor(F const& f) {
-        return {std::type_index(typeid(T)), [g = f](std::any const& a) -> ID_TYPE {
-                    if constexpr (std::is_void_v<T>)
-                        return g();
-                    else
-                        return g(std::any_cast<T const&>(a));
-                }};
-    }
-
-    template <class T, class F>
-    inline void
-    register_any_visitor(F const& f) {
-        /* std::cout << "Register visitor for type " << std::quoted(typeid(T).name()) << '\n'; */
-        any_flush_vistors_.insert(to_any_visitor<T>(f));
-    }
-
     Store() {
-        register_any_visitor<Collection::Ptr>([this](auto c) {
-            CollectionPtr n;
-            CreateResource<Collection>(Collection(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<CollectionCommit::Ptr>([this](auto c) {
-            using T = CollectionCommit;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<SchemaCommit::Ptr>([this](auto c) {
-            using T = SchemaCommit;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<FieldCommit::Ptr>([this](auto c) {
-            using T = FieldCommit;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<Field::Ptr>([this](auto c) {
-            using T = Field;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<FieldElement::Ptr>([this](auto c) {
-            using T = FieldElement;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<PartitionCommit::Ptr>([this](auto c) {
-            using T = PartitionCommit;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<Partition::Ptr>([this](auto c) {
-            using T = Partition;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<Segment::Ptr>([this](auto c) {
-            using T = Segment;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<SegmentCommit::Ptr>([this](auto c) {
-            using T = SegmentCommit;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
-        register_any_visitor<SegmentFile::Ptr>([this](auto c) {
-            using T = SegmentFile;
-            using PtrT = typename T::Ptr;
-            PtrT n;
-            CreateResource<T>(T(*c), n);
-            return n->GetID();
-        });
     }
 
     void
-- 
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