Using SegmentSnapshotPtr instead of SegmentSnapshot (#532)

pingcap · Mar 20, 2020 · f9b445d · f9b445d
1 parent f0e3aa0
commit f9b445d
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Showing 5 changed files with 138 additions and 122 deletions.
diff --git a/dbms/src/Storages/DeltaMerge/DeltaMergeStore.cpp b/dbms/src/Storages/DeltaMerge/DeltaMergeStore.cpp
@@ -541,8 +541,12 @@ BlockInputStreams DeltaMergeStore::readRaw(const Context &       db_context,
         {
             (void)handle;
             if (read_segments.empty() || read_segments.count(segment->segmentId()))
-                tasks.push(
-                    std::make_shared<SegmentReadTask>(segment, segment->createSnapshot(*dm_context), HandleRanges{segment->getRange()}));
+            {
+                auto segment_snap = segment->createSnapshot(*dm_context);
+                if (unlikely(!segment_snap))
+                    throw Exception("Failed to get segment snap", ErrorCodes::LOGICAL_ERROR);
+                tasks.push(std::make_shared<SegmentReadTask>(segment, segment_snap, HandleRanges{segment->getRange()}));
+            }
         }
     }
 
@@ -607,8 +611,11 @@ BlockInputStreams DeltaMergeStore::read(const Context &       db_context,
             {
                 if (tasks.empty() || tasks.back()->segment != seg_it->second)
                 {
-                    auto segment = seg_it->second;
-                    tasks.push(std::make_shared<SegmentReadTask>(segment, segment->createSnapshot(*dm_context)));
+                    auto segment      = seg_it->second;
+                    auto segment_snap = segment->createSnapshot(*dm_context);
+                    if (unlikely(!segment_snap))
+                        throw Exception("Failed to get segment snap", ErrorCodes::LOGICAL_ERROR);
+                    tasks.push(std::make_shared<SegmentReadTask>(segment, segment_snap));
                 }
 
                 tasks.back()->addRange(req_range);
@@ -1002,7 +1009,7 @@ SegmentPair DeltaMergeStore::segmentSplit(DMContext & dm_context, const SegmentP
 {
     LOG_DEBUG(log, "Split segment " << segment->info());
 
-    SegmentSnapshot segment_snap;
+    SegmentSnapshotPtr segment_snap;
 
     {
         std::shared_lock lock(read_write_mutex);
@@ -1079,8 +1086,8 @@ void DeltaMergeStore::segmentMerge(DMContext & dm_context, const SegmentPtr & le
 {
     LOG_DEBUG(log, "Merge Segment [" << left->info() << "] and [" << right->info() << "]");
 
-    SegmentSnapshot left_snap;
-    SegmentSnapshot right_snap;
+    SegmentSnapshotPtr left_snap;
+    SegmentSnapshotPtr right_snap;
 
     {
         std::shared_lock lock(read_write_mutex);
@@ -1161,7 +1168,7 @@ SegmentPtr DeltaMergeStore::segmentMergeDelta(DMContext & dm_context, const Segm
 {
     LOG_DEBUG(log, (is_foreground ? "Foreground" : "Background") << " merge delta, segment [" << segment->segmentId() << "]");
 
-    SegmentSnapshot segment_snap;
+    SegmentSnapshotPtr segment_snap;
 
     {
         std::shared_lock lock(read_write_mutex);

diff --git a/dbms/src/Storages/DeltaMerge/DeltaValueSpace.h b/dbms/src/Storages/DeltaMerge/DeltaValueSpace.h
@@ -5,6 +5,7 @@
 #include <IO/WriteHelpers.h>
 #include <Storages/DeltaMerge/DeltaMergeDefines.h>
 #include <Storages/DeltaMerge/DeltaMergeHelpers.h>
+#include <Storages/DeltaMerge/StoragePool.h>
 #include <Storages/Page/PageDefines.h>
 
 namespace DB
@@ -17,8 +18,6 @@ class DeltaValueSpace;
 using DeltaValueSpacePtr = std::shared_ptr<DeltaValueSpace>;
 struct WriteBatches;
 class StoragePool;
-struct StorageSnapshot;
-using StorageSnapshotPtr = std::shared_ptr<StorageSnapshot>;
 struct DMContext;
 
 struct BlockOrDelete