perf(scan): reuse immutable snapshot read views

Author: wangyong9999

include/paimon/scan_context.h

@@ -37,6 +37,7 @@ class ScanFilter;
 class Executor;
 class MemoryPool;
 class Predicate;
+class SnapshotReadView;
 
 /// `ScanContext` is some configuration for table scan operations.
 ///
@@ -56,6 +57,18 @@ class PAIMON_EXPORT ScanContext {
                 const std::map<std::string, std::string>& options,
                 const std::shared_ptr<Cache>& cache);
 
+    ScanContext(const std::string& path, bool is_streaming_mode, std::optional<int32_t> limit,
+                const std::shared_ptr<ScanFilter>& scan_filter,
+                const std::shared_ptr<GlobalIndexResult>& global_index_result,
+                const std::shared_ptr<RealtimeContext>& realtime_context,
+                const std::shared_ptr<MemoryPool>& memory_pool,
+                const std::shared_ptr<Executor>& executor,
+                const std::shared_ptr<FileSystem>& specific_file_system,
+                const std::optional<std::string>& table_schema,
+                const std::map<std::string, std::string>& options,
+                const std::shared_ptr<Cache>& cache,
+                const std::shared_ptr<const SnapshotReadView>& snapshot_read_view);
+
     ~ScanContext();
 
     const std::string& GetPath() const {
@@ -105,6 +118,10 @@ class PAIMON_EXPORT ScanContext {
         return cache_;
     }
 
+    std::shared_ptr<const SnapshotReadView> GetSnapshotReadView() const {
+        return snapshot_read_view_;
+    }
+
  private:
     std::string path_;
     bool is_streaming_mode_;
@@ -118,6 +135,7 @@ class PAIMON_EXPORT ScanContext {
     std::optional<std::string> table_schema_;
     std::map<std::string, std::string> options_;
     std::shared_ptr<Cache> cache_;
+    std::shared_ptr<const SnapshotReadView> snapshot_read_view_;
 };
 
 /// Filter configuration for table scan operations
@@ -220,6 +238,15 @@ class PAIMON_EXPORT ScanContextBuilder {
     /// @return Reference to this builder for method chaining.
     ScanContextBuilder& WithCache(const std::shared_ptr<Cache>& cache);
 
+    /// Reuse the immutable parsed snapshot metadata from an earlier batch scan plan.
+    ///
+    /// The view must belong to the same normalized table path and branch. Snapshot read views are
+    /// supported for non-streaming latest-snapshot scans.
+    /// @param snapshot_read_view A read view returned by `Plan::GetSnapshotReadView()`.
+    /// @return Reference to this builder for method chaining.
+    ScanContextBuilder& WithSnapshotReadView(
+        const std::shared_ptr<const SnapshotReadView>& snapshot_read_view);
+
     /// Build and return a `ScanContext` instance with input validation.
     /// @return Result containing the constructed `ScanContext` or an error status.
     Result<std::unique_ptr<ScanContext>> Finish();

include/paimon/table/source/plan.h

@@ -23,6 +23,7 @@
 #include <optional>
 #include <vector>
 
+#include "paimon/table/source/snapshot_read_view.h"
 #include "paimon/table/source/split.h"
 
 namespace paimon {
@@ -34,5 +35,13 @@ class PAIMON_EXPORT Plan {
     virtual const std::vector<std::shared_ptr<Split>>& Splits() const = 0;
     /// Snapshot id of this plan, return `std::nullopt` if the table is empty.
     virtual std::optional<int64_t> SnapshotId() const = 0;
+    /// Immutable snapshot metadata used to build this plan.
+    ///
+    /// The returned view can be injected into a later batch scan to reuse the already resolved and
+    /// parsed snapshot. Only non-streaming, non-real-time latest-snapshot plans publish a reusable
+    /// view; other plans return `nullptr`.
+    virtual std::shared_ptr<const SnapshotReadView> GetSnapshotReadView() const {
+        return nullptr;
+    }
 };
 }  // namespace paimon

include/paimon/table/source/snapshot_read_view.h

@@ -0,0 +1,61 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <string>
+
+#include "paimon/visibility.h"
+
+namespace paimon {
+
+class SnapshotReadViewImpl;
+
+/// An immutable, process-local view of the snapshot and table-schema metadata used to create a
+/// scan plan.
+///
+/// A view is bound to one base table path and branch. Pass a view returned by `Plan` to
+/// `ScanContextBuilder::WithSnapshotReadView()` to plan another batch scan against the same
+/// parsed planning metadata without resolving the latest snapshot or schema again. Views are
+/// published and accepted only for non-streaming, non-real-time latest-snapshot scans. A missing
+/// snapshot id represents an empty table at the time the view was created. The base path identity
+/// is also used by supported system-table scans such as `$ro`, because they consume the same
+/// snapshot and schema metadata.
+class PAIMON_EXPORT SnapshotReadView {
+ public:
+    virtual ~SnapshotReadView() = default;
+
+    /// Normalized base table path this view belongs to, without a system-table suffix.
+    virtual const std::string& TablePath() const = 0;
+
+    /// Normalized branch this view belongs to.
+    virtual const std::string& Branch() const = 0;
+
+    /// Snapshot id captured by this view, or `std::nullopt` if the table was empty.
+    virtual std::optional<int64_t> SnapshotId() const = 0;
+
+ private:
+    SnapshotReadView() = default;
+
+    friend class SnapshotReadViewImpl;
+};
+
+}  // namespace paimon

src/paimon/core/operation/scan_context.cpp

@@ -39,6 +39,22 @@ ScanContext::ScanContext(const std::string& path, bool is_streaming_mode,
                          const std::optional<std::string>& table_schema,
                          const std::map<std::string, std::string>& options,
                          const std::shared_ptr<Cache>& cache)
+    : ScanContext(path, is_streaming_mode, limit, scan_filter, global_index_result,
+                  realtime_context, memory_pool, executor, specific_file_system, table_schema,
+                  options, cache, nullptr) {}
+
+ScanContext::ScanContext(const std::string& path, bool is_streaming_mode,
+                         std::optional<int32_t> limit,
+                         const std::shared_ptr<ScanFilter>& scan_filter,
+                         const std::shared_ptr<GlobalIndexResult>& global_index_result,
+                         const std::shared_ptr<RealtimeContext>& realtime_context,
+                         const std::shared_ptr<MemoryPool>& memory_pool,
+                         const std::shared_ptr<Executor>& executor,
+                         const std::shared_ptr<FileSystem>& specific_file_system,
+                         const std::optional<std::string>& table_schema,
+                         const std::map<std::string, std::string>& options,
+                         const std::shared_ptr<Cache>& cache,
+                         const std::shared_ptr<const SnapshotReadView>& snapshot_read_view)
     : path_(path),
       is_streaming_mode_(is_streaming_mode),
       limit_(limit),
@@ -50,7 +66,8 @@ ScanContext::ScanContext(const std::string& path, bool is_streaming_mode,
       specific_file_system_(specific_file_system),
       table_schema_(table_schema),
       options_(options),
-      cache_(cache) {}
+      cache_(cache),
+      snapshot_read_view_(snapshot_read_view) {}
 
 ScanContext::~ScanContext() = default;
 
@@ -72,6 +89,7 @@ class ScanContextBuilder::Impl {
         table_schema_ = std::nullopt;
         options_.clear();
         cache_.reset();
+        snapshot_read_view_.reset();
     }
 
  private:
@@ -89,6 +107,7 @@ class ScanContextBuilder::Impl {
     std::optional<std::string> table_schema_;
     std::map<std::string, std::string> options_;
     std::shared_ptr<Cache> cache_;
+    std::shared_ptr<const SnapshotReadView> snapshot_read_view_;
 };
 
 ScanContextBuilder::ScanContextBuilder(const std::string& path)
@@ -173,6 +192,12 @@ ScanContextBuilder& ScanContextBuilder::WithCache(const std::shared_ptr<Cache>&
     return *this;
 }
 
+ScanContextBuilder& ScanContextBuilder::WithSnapshotReadView(
+    const std::shared_ptr<const SnapshotReadView>& snapshot_read_view) {
+    impl_->snapshot_read_view_ = snapshot_read_view;
+    return *this;
+}
+
 Result<std::unique_ptr<ScanContext>> ScanContextBuilder::Finish() {
     PAIMON_ASSIGN_OR_RAISE(impl_->path_, PathUtil::NormalizePath(impl_->path_));
     if (impl_->path_.empty()) {
@@ -184,7 +209,7 @@ Result<std::unique_ptr<ScanContext>> ScanContextBuilder::Finish() {
                                      impl_->bucket_filter_),
         impl_->global_index_result_, impl_->realtime_context_, impl_->memory_pool_,
         impl_->executor_, impl_->specific_file_system_, impl_->table_schema_, impl_->options_,
-        impl_->cache_);
+        impl_->cache_, impl_->snapshot_read_view_);
     impl_->Reset();
     return ctx;
 }

src/paimon/core/table/source/data_evolution_batch_scan.cpp

@@ -25,6 +25,7 @@
 #include "paimon/core/global_index/global_index_scan_impl.h"
 #include "paimon/core/global_index/indexed_split_impl.h"
 #include "paimon/core/table/source/data_split_impl.h"
+#include "paimon/core/table/source/snapshot_read_view_impl.h"
 #include "paimon/core/utils/snapshot_manager.h"
 #include "paimon/global_index/bitmap_global_index_result.h"
 
@@ -44,6 +45,11 @@ DataEvolutionBatchScan::DataEvolutionBatchScan(
       executor_(executor) {}
 
 Result<std::shared_ptr<Plan>> DataEvolutionBatchScan::CreatePlan() {
+    std::shared_ptr<const SnapshotReadView> snapshot_read_view =
+        snapshot_reader_->GetSnapshotReadView();
+    if (snapshot_read_view && !snapshot_read_view->SnapshotId()) {
+        return PlanImpl::EmptyPlan(snapshot_read_view);
+    }
     std::optional<std::vector<Range>> row_ranges;
     std::shared_ptr<GlobalIndexResult> final_global_index_result = global_index_result_;
     if (!final_global_index_result) {
@@ -52,14 +58,22 @@ Result<std::shared_ptr<Plan>> DataEvolutionBatchScan::CreatePlan() {
             final_global_index_result = index_result;
             PAIMON_ASSIGN_OR_RAISE(row_ranges, index_result->ToRanges());
         }
+        // EvalGlobalIndex captures the latest snapshot before consulting its index. Refresh the
+        // local copy so both negative and positive results publish and reuse that exact view.
+        snapshot_read_view = snapshot_reader_->GetSnapshotReadView();
     } else {
         PAIMON_ASSIGN_OR_RAISE(row_ranges, final_global_index_result->ToRanges());
     }
     if (!row_ranges) {
         return batch_scan_->CreatePlan();
     }
     if (row_ranges.value().empty()) {
-        return PlanImpl::EmptyPlan();
+        if (snapshot_read_view && snapshot_read_view->SnapshotId()) {
+            return std::make_shared<PlanImpl>(snapshot_read_view->SnapshotId(),
+                                              std::vector<std::shared_ptr<Split>>(),
+                                              snapshot_read_view);
+        }
+        return PlanImpl::EmptyPlan(snapshot_read_view);
     }
     PAIMON_ASSIGN_OR_RAISE(RowRangeIndex row_range_index,
                            RowRangeIndex::Create(row_ranges.value()));
@@ -133,7 +147,8 @@ Result<std::shared_ptr<Plan>> DataEvolutionBatchScan::WrapToIndexedSplits(
         }
         indexed_splits.push_back(std::make_shared<IndexedSplitImpl>(data_split, expected, scores));
     }
-    return std::make_shared<PlanImpl>(data_plan->SnapshotId(), indexed_splits);
+    return std::make_shared<PlanImpl>(data_plan->SnapshotId(), indexed_splits,
+                                      data_plan->GetSnapshotReadView());
 }
 
 Result<std::shared_ptr<GlobalIndexResult>> DataEvolutionBatchScan::EvalGlobalIndex() const {
@@ -145,24 +160,40 @@ Result<std::shared_ptr<GlobalIndexResult>> DataEvolutionBatchScan::EvalGlobalInd
         return std::shared_ptr<GlobalIndexResult>(nullptr);
     }
     auto partition_filter = batch_scan_->GetPartitionPredicate();
-    // TODO(lisizhuo.lsz): support time travel
-    std::optional<Snapshot> snapshot;
-    const std::shared_ptr<SnapshotManager>& snapshot_manager =
-        snapshot_reader_->GetSnapshotManager();
-    if (const std::optional<int64_t>& snapshot_id = core_options_.GetScanSnapshotId()) {
-        PAIMON_ASSIGN_OR_RAISE(Snapshot loaded_snapshot,
-                               snapshot_manager->LoadSnapshot(snapshot_id.value()));
-        snapshot = std::move(loaded_snapshot);
+    StartupMode startup_mode = core_options_.GetStartupMode();
+    std::shared_ptr<const Snapshot> snapshot;
+    if (!(startup_mode == StartupMode::LatestFull() || startup_mode == StartupMode::Latest())) {
+        // Snapshot read views deliberately support latest scans only. Preserve main's non-latest
+        // planning path, including an explicitly selected snapshot and the caller-owned context.
+        // TODO(lisizhuo.lsz): support tag/timestamp time travel.
+        std::optional<Snapshot> loaded_snapshot;
+        const std::shared_ptr<SnapshotManager>& snapshot_manager =
+            snapshot_reader_->GetSnapshotManager();
+        if (const std::optional<int64_t>& snapshot_id = core_options_.GetScanSnapshotId()) {
+            PAIMON_ASSIGN_OR_RAISE(Snapshot selected_snapshot,
+                                   snapshot_manager->LoadSnapshot(snapshot_id.value()));
+            loaded_snapshot = std::move(selected_snapshot);
+        } else {
+            PAIMON_ASSIGN_OR_RAISE(loaded_snapshot, snapshot_manager->LatestSnapshot());
+        }
+        if (!loaded_snapshot) {
+            return Status::Invalid("not found latest snapshot");
+        }
+        snapshot = std::make_shared<const Snapshot>(std::move(loaded_snapshot).value());
     } else {
-        PAIMON_ASSIGN_OR_RAISE(snapshot, snapshot_manager->LatestSnapshot());
-    }
-    if (!snapshot) {
-        return Status::Invalid("not found latest snapshot");
+        // Capture the latest snapshot through the shared SnapshotReader before evaluating the
+        // index. The subsequent data scan then consumes the same immutable view, avoiding both a
+        // second latest-snapshot lookup and a row-id/snapshot race.
+        PAIMON_ASSIGN_OR_RAISE(std::shared_ptr<const SnapshotReadView> snapshot_read_view,
+                               snapshot_reader_->CaptureLatestSnapshotReadView());
+        PAIMON_ASSIGN_OR_RAISE(snapshot, SnapshotReadViewImpl::GetSnapshot(snapshot_read_view));
+        if (!snapshot) {
+            return std::shared_ptr<GlobalIndexResult>(nullptr);
+        }
     }
-
     PAIMON_ASSIGN_OR_RAISE(
         std::unique_ptr<GlobalIndexScanImpl> index_scan,
-        GlobalIndexScanImpl::Create(table_path_, table_schema_, snapshot.value(), partition_filter,
+        GlobalIndexScanImpl::Create(table_path_, table_schema_, *snapshot, partition_filter,
                                     core_options_, executor_, pool_));
     return index_scan->Scan(predicate);
 }

src/paimon/core/table/source/data_table_batch_scan.cpp

@@ -90,7 +90,7 @@ Result<std::shared_ptr<Plan>> DataTableBatchScan::ApplyPushDownLimit(
         std::dynamic_pointer_cast<StartingScanner::CurrentSnapshot>(scan_result);
     if (!current_scan_result) {
         // NoSnapshot
-        return PlanImpl::EmptyPlan();
+        return snapshot_reader_->EmptyPlan();
     }
     if (!CanPushDownLimit()) {
         return current_scan_result->GetPlan();
@@ -126,7 +126,9 @@ Result<std::shared_ptr<Plan>> DataTableBatchScan::ApplyPushDownLimit(
                              "rows.",
                              limited_data_splits.size(), splits.size(), push_down_limit_.value(),
                              scanned_row_count);
-            return std::make_shared<PlanImpl>(snapshot_id, limited_data_splits);
+            return std::make_shared<PlanImpl>(
+                snapshot_id, limited_data_splits,
+                current_scan_result->GetPlan()->GetSnapshotReadView());
         }
     }
     return current_scan_result->GetPlan();

src/paimon/core/table/source/plan_impl.cpp

@@ -27,4 +27,13 @@ const std::shared_ptr<Plan> PlanImpl::EmptyPlan() {
     return empty_plan;
 }
 
+const std::shared_ptr<Plan> PlanImpl::EmptyPlan(
+    const std::shared_ptr<const SnapshotReadView>& snapshot_read_view) {
+    if (!snapshot_read_view) {
+        return EmptyPlan();
+    }
+    return std::make_shared<PlanImpl>(std::optional<int64_t>(),
+                                      std::vector<std::shared_ptr<Split>>(), snapshot_read_view);
+}
+
 }  // namespace paimon

src/paimon/core/table/source/plan_impl.h

@@ -33,7 +33,12 @@ class PlanImpl : public Plan {
  public:
     PlanImpl(const std::optional<int64_t>& snapshot_id,
              const std::vector<std::shared_ptr<Split>>& splits)
-        : snapshot_id_(snapshot_id), splits_(splits) {}
+        : PlanImpl(snapshot_id, splits, nullptr) {}
+
+    PlanImpl(const std::optional<int64_t>& snapshot_id,
+             const std::vector<std::shared_ptr<Split>>& splits,
+             const std::shared_ptr<const SnapshotReadView>& snapshot_read_view)
+        : snapshot_id_(snapshot_id), splits_(splits), snapshot_read_view_(snapshot_read_view) {}
 
     std::optional<int64_t> SnapshotId() const override {
         return snapshot_id_;
@@ -43,10 +48,18 @@ class PlanImpl : public Plan {
         return splits_;
     }
 
+    std::shared_ptr<const SnapshotReadView> GetSnapshotReadView() const override {
+        return snapshot_read_view_;
+    }
+
     static const std::shared_ptr<Plan> EmptyPlan();
 
+    static const std::shared_ptr<Plan> EmptyPlan(
+        const std::shared_ptr<const SnapshotReadView>& snapshot_read_view);
+
  private:
     std::optional<int64_t> snapshot_id_;
     std::vector<std::shared_ptr<Split>> splits_;
+    std::shared_ptr<const SnapshotReadView> snapshot_read_view_;
 };
 }  // namespace paimon