Fix deadlock happen in mvcc.

dbms/src/Storages/Page/V3/PageDirectory.cpp

@@ -23,9 +23,8 @@ namespace PS::V3
  * VersionedPageEntries methods *
  ********************************/
 
-std::optional<PageEntryV3> VersionedPageEntries::getEntry(UInt64 seq) const
+std::optional<PageEntryV3> VersionedPageEntries::getEntryNotSafe(UInt64 seq) const
 {
- auto page_lock = acquireLock();
  // entries are sorted by <ver, epoch>, find the first one less than <ver+1, 0>
  if (auto iter = MapUtils::findLess(entries, PageVersionType(seq + 1));
  iter != entries.end())
@@ -36,6 +35,12 @@ std::optional<PageEntryV3> VersionedPageEntries::getEntry(UInt64 seq) const
  return std::nullopt;
 }
 
+std::optional<PageEntryV3> VersionedPageEntries::getEntry(UInt64 seq) const
+{
+ auto page_lock = acquireLock();
+ return getEntryNotSafe(seq);
+}
+
 std::pair<VersionedEntries, PageSize> VersionedPageEntries::getEntriesByBlobId(BlobFileId blob_id)
 {
  PageSize single_page_size = 0;
@@ -243,7 +248,12 @@ void PageDirectory::apply(PageEntriesEdit && edit)
  break;
  }
 
- if (auto entry = iter->second->getEntry(last_sequence); entry)
+ // If we already hold the lock from `r.ori_page_id`, Then we should not request it again.
+ // This can happen when r.ori_page_id have other operating in current writebatch
+ if (auto entry = (updating_locks.find(r.ori_page_id) != updating_locks.end()
+ ? iter->second->getEntryNotSafe(last_sequence)
+ : iter->second->getEntry(last_sequence));
+ entry)
  {
  // copy the entry to be ref
  updating_pages[idx]->createNewVersion(last_sequence + 1, *entry);

dbms/src/Storages/Page/V3/PageDirectory.h

@@ -71,6 +71,8 @@ class VersionedPageEntries
 
  std::optional<PageEntryV3> getEntry(UInt64 seq) const;
 
+ std::optional<PageEntryV3> getEntryNotSafe(UInt64 seq) const;
+
  /**
  * Take out the `VersionedEntries` which exist in the `BlobFileId`.
  * Also return the total size of entries.

dbms/src/Storages/Page/V3/tests/gtest_page_directory.cpp

@@ -399,6 +399,32 @@ try
 }
 CATCH
 
+TEST_F(PageDirectoryTest, TestRefWontDeadLock)
+{
+ PageEntriesEdit edit;
+ {
+ // 1. batch.putExternal(0, 0);
+ PageEntryV3 entry1;
+ edit.put(0, entry1);
+
+ // 2. batch.putRefPage(1, 0);
+ edit.ref(1, 0);
+ }
+
+ dir.apply(std::move(edit));
+
+ PageEntriesEdit edit2;
+ {
+ // 1. batch.putRefPage(2, 1); // ref 2 -> 1 -> 0
+ edit2.ref(2, 1);
+
+ // 2. batch.delPage(1); // free ref 1 -> 0
+ edit2.del(1);
+ }
+
+ dir.apply(std::move(edit2));
+}
+
 #define INSERT_BLOBID_ENTRY(BLOBID, VERSION) \
  PageEntryV3 entry_v##VERSION{.file_id = (BLOBID), .size = (VERSION), .offset = 0x123, .checksum = 0x4567}; \
  entries.createNewVersion((VERSION), entry_v##VERSION);