optimize ps v3 restore (#5163)

ref #4914

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

@@ -478,7 +478,7 @@ PageSize VersionedPageEntries::getEntriesByBlobIds(
 bool VersionedPageEntries::cleanOutdatedEntries(
  UInt64 lowest_seq,
  std::map<PageIdV3Internal, std::pair<PageVersion, Int64>> * normal_entries_to_deref,
- PageEntriesV3 & entries_removed,
+ PageEntriesV3 * entries_removed,
  const PageLock & /*page_lock*/)
 {
  if (type == EditRecordType::VAR_EXTERNAL)
@@ -541,7 +541,10 @@ bool VersionedPageEntries::cleanOutdatedEntries(
  {
  if (iter->second.being_ref_count == 1)
  {
- entries_removed.emplace_back(iter->second.entry);
+ if (entries_removed)
+ {
+ entries_removed->emplace_back(iter->second.entry);
+ }
  iter = entries.erase(iter);
  }
  // The `being_ref_count` for this version is valid. While for older versions,
@@ -551,7 +554,10 @@ bool VersionedPageEntries::cleanOutdatedEntries(
  else
  {
  // else there are newer "entry" in the version list, the outdated entries should be removed
- entries_removed.emplace_back(iter->second.entry);
+ if (entries_removed)
+ {
+ entries_removed->emplace_back(iter->second.entry);
+ }
  iter = entries.erase(iter);
  }
  }
@@ -564,7 +570,7 @@ bool VersionedPageEntries::cleanOutdatedEntries(
  return entries.empty() || (entries.size() == 1 && entries.begin()->second.isDelete());
 }
 
-bool VersionedPageEntries::derefAndClean(UInt64 lowest_seq, PageIdV3Internal page_id, const PageVersion & deref_ver, const Int64 deref_count, PageEntriesV3 & entries_removed)
+bool VersionedPageEntries::derefAndClean(UInt64 lowest_seq, PageIdV3Internal page_id, const PageVersion & deref_ver, const Int64 deref_count, PageEntriesV3 * entries_removed)
 {
  auto page_lock = acquireLock();
  if (type == EditRecordType::VAR_EXTERNAL)
@@ -1239,7 +1245,7 @@ bool PageDirectory::tryDumpSnapshot(const ReadLimiterPtr & read_limiter, const W
  return done_any_io;
 }
 
-PageEntriesV3 PageDirectory::gcInMemEntries()
+PageEntriesV3 PageDirectory::gcInMemEntries(bool return_removed_entries)
 {
  UInt64 lowest_seq = sequence.load();
 
@@ -1303,7 +1309,7 @@ PageEntriesV3 PageDirectory::gcInMemEntries()
  const bool all_deleted = iter->second->cleanOutdatedEntries(
  lowest_seq,
  &normal_entries_to_deref,
- all_del_entries,
+ return_removed_entries ? &all_del_entries : nullptr,
  iter->second->acquireLock());
 
  {
@@ -1342,7 +1348,7 @@ PageEntriesV3 PageDirectory::gcInMemEntries()
  page_id,
  /*deref_ver=*/deref_counter.first,
  /*deref_count=*/deref_counter.second,
- all_del_entries);
+ return_removed_entries ? &all_del_entries : nullptr);
 
  if (all_deleted)
  {

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

@@ -223,14 +223,14 @@ class VersionedPageEntries
  bool cleanOutdatedEntries(
  UInt64 lowest_seq,
  std::map<PageIdV3Internal, std::pair<PageVersion, Int64>> * normal_entries_to_deref,
- PageEntriesV3 & entries_removed,
+ PageEntriesV3 * entries_removed,
  const PageLock & page_lock);
  bool derefAndClean(
  UInt64 lowest_seq,
  PageIdV3Internal page_id,
  const PageVersion & deref_ver,
  Int64 deref_count,
- PageEntriesV3 & entries_removed);
+ PageEntriesV3 * entries_removed);
 
  void collapseTo(UInt64 seq, PageIdV3Internal page_id, PageEntriesEdit & edit);
 
@@ -360,7 +360,9 @@ class PageDirectory
 
  bool tryDumpSnapshot(const ReadLimiterPtr & read_limiter = nullptr, const WriteLimiterPtr & write_limiter = nullptr);
 
- PageEntriesV3 gcInMemEntries();
+ // Perform a GC for in-memory entries and return the removed entries.
+ // If `return_removed_entries` is false, then just return an empty set.
+ PageEntriesV3 gcInMemEntries(bool return_removed_entries = true);
 
  std::set<PageId> getAliveExternalIds(NamespaceId ns_id) const;
 

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

@@ -44,7 +44,8 @@ PageDirectoryPtr PageDirectoryFactory::createFromReader(String storage_name, WAL
 
  // After restoring from the disk, we need cleanup all invalid entries in memory, or it will
  // try to run GC again on some entries that are already marked as invalid in BlobStore.
- dir->gcInMemEntries();
+ // It's no need to remove the expired entries in BlobStore, so skip filling removed_entries to imporve performance.
+ dir->gcInMemEntries(/*return_removed_entries=*/false);
  LOG_FMT_INFO(DB::Logger::get("PageDirectoryFactory", storage_name), "PageDirectory restored [max_page_id={}] [max_applied_ver={}]", dir->getMaxId(), dir->sequence);
 
  if (blob_stats)
@@ -84,7 +85,8 @@ PageDirectoryPtr PageDirectoryFactory::createFromEdit(String storage_name, FileP
 
  // After restoring from the disk, we need cleanup all invalid entries in memory, or it will
  // try to run GC again on some entries that are already marked as invalid in BlobStore.
- dir->gcInMemEntries();
+ // It's no need to remove the expired entries in BlobStore when restore, so no need to fill removed_entries.
+ dir->gcInMemEntries(/*return_removed_entries=*/false);
 
  if (blob_stats)
  {

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

@@ -644,14 +644,14 @@ class VersionedEntriesTest : public ::testing::Test
  {
  DerefCounter deref_counter;
  PageEntriesV3 removed_entries;
- bool all_removed = entries.cleanOutdatedEntries(seq, &deref_counter, removed_entries, entries.acquireLock());
+ bool all_removed = entries.cleanOutdatedEntries(seq, &deref_counter, &removed_entries, entries.acquireLock());
  return {all_removed, removed_entries, deref_counter};
  }
 
  std::tuple<bool, PageEntriesV3> runDeref(UInt64 seq, PageVersion ver, Int64 decrease_num)
  {
  PageEntriesV3 removed_entries;
- bool all_removed = entries.derefAndClean(seq, buildV3Id(TEST_NAMESPACE_ID, page_id), ver, decrease_num, removed_entries);
+ bool all_removed = entries.derefAndClean(seq, buildV3Id(TEST_NAMESPACE_ID, page_id), ver, decrease_num, &removed_entries);
  return {all_removed, removed_entries};
  }