Some fixes and enhancements to ldb repair (#8544)

Summary:
* Basic handling of SST file with just range tombstones rather than
failing assertion about smallest_seqno <= largest_seqno
* Adds --verbose option so that there exists a way to see the INFO
output from Repairer.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8544

Test Plan: unit test added, manual testing for --verbose

Reviewed By: ajkr

Differential Revision: D29954805

Pulled By: pdillinger

fbshipit-source-id: 696af25805fc36cc178b04ba6045922a22625fd9

db/repair.cc

@@ -300,6 +300,8 @@ class Repairer {
     }
 
     for (size_t path_id = 0; path_id < to_search_paths.size(); path_id++) {
+      ROCKS_LOG_INFO(db_options_.info_log, "Searching path %s\n",
+                     to_search_paths[path_id].c_str());
       status = env_->GetChildren(to_search_paths[path_id], &filenames);
       if (!status.ok()) {
         return status;
@@ -587,6 +589,30 @@ class Repairer {
                      t->meta.fd.GetNumber(), counter,
                      status.ToString().c_str());
     }
+    if (status.ok()) {
+      // XXX/FIXME: This is just basic, naive handling of range tombstones,
+      // like call to UpdateBoundariesForRange in builder.cc where we assume
+      // an SST file is a full sorted run. This probably needs the extra logic
+      // from compaction_job.cc around call to UpdateBoundariesForRange (to
+      // handle range tombstones extendingg beyond range of other entries).
+      ReadOptions ropts;
+      std::unique_ptr<FragmentedRangeTombstoneIterator> r_iter;
+      status = table_cache_->GetRangeTombstoneIterator(
+          ropts, cfd->internal_comparator(), t->meta, &r_iter);
+
+      if (r_iter) {
+        r_iter->SeekToFirst();
+
+        while (r_iter->Valid()) {
+          auto tombstone = r_iter->Tombstone();
+          auto kv = tombstone.Serialize();
+          t->meta.UpdateBoundariesForRange(
+              kv.first, tombstone.SerializeEndKey(), tombstone.seq_,
+              cfd->internal_comparator());
+          r_iter->Next();
+        }
+      }
+    }
     return status;
   }
 

db/repair_test.cc

@@ -3,6 +3,7 @@
 //  COPYING file in the root directory) and Apache 2.0 License
 //  (found in the LICENSE.Apache file in the root directory).
 
+#include "rocksdb/options.h"
 #ifndef ROCKSDB_LITE
 
 #include <algorithm>
@@ -66,6 +67,35 @@ TEST_F(RepairTest, LostManifest) {
   ASSERT_EQ(Get("key2"), "val2");
 }
 
+TEST_F(RepairTest, LostManifestMoreDbFeatures) {
+  // Add a couple SST files, delete the manifest, and verify RepairDB() saves
+  // the day.
+  ASSERT_OK(Put("key", "val"));
+  ASSERT_OK(Put("key2", "val2"));
+  ASSERT_OK(Put("key3", "val3"));
+  ASSERT_OK(Put("key4", "val4"));
+  ASSERT_OK(Flush());
+  // Test an SST file containing only a range tombstone
+  ASSERT_OK(db_->DeleteRange(WriteOptions(), db_->DefaultColumnFamily(), "key2",
+                             "key3z"));
+  ASSERT_OK(Flush());
+  // Need to get path before Close() deletes db_, but delete it after Close() to
+  // ensure Close() didn't change the manifest.
+  std::string manifest_path =
+      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());
+
+  Close();
+  ASSERT_OK(env_->FileExists(manifest_path));
+  ASSERT_OK(env_->DeleteFile(manifest_path));
+  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
+  Reopen(CurrentOptions());
+
+  ASSERT_EQ(Get("key"), "val");
+  ASSERT_EQ(Get("key2"), "NOT_FOUND");
+  ASSERT_EQ(Get("key3"), "NOT_FOUND");
+  ASSERT_EQ(Get("key4"), "val4");
+}
+
 TEST_F(RepairTest, CorruptManifest) {
   // Manifest is in an invalid format. Expect a full recovery.
   ASSERT_OK(Put("key", "val"));

tools/ldb_cmd.cc

@@ -3079,20 +3079,26 @@ void CheckPointCommand::DoCommand() {
 
 // ----------------------------------------------------------------------------
 
+const std::string RepairCommand::ARG_VERBOSE = "verbose";
+
 RepairCommand::RepairCommand(const std::vector<std::string>& /*params*/,
                              const std::map<std::string, std::string>& options,
                              const std::vector<std::string>& flags)
-    : LDBCommand(options, flags, false, BuildCmdLineOptions({})) {}
+    : LDBCommand(options, flags, false, BuildCmdLineOptions({ARG_VERBOSE})) {
+  verbose_ = IsFlagPresent(flags, ARG_VERBOSE);
+}
 
 void RepairCommand::Help(std::string& ret) {
   ret.append("  ");
   ret.append(RepairCommand::Name());
+  ret.append(" [--" + ARG_VERBOSE + "]");
   ret.append("\n");
 }
 
 void RepairCommand::OverrideBaseOptions() {
   LDBCommand::OverrideBaseOptions();
-  options_.info_log.reset(new StderrLogger(InfoLogLevel::WARN_LEVEL));
+  auto level = verbose_ ? InfoLogLevel::INFO_LEVEL : InfoLogLevel::WARN_LEVEL;
+  options_.info_log.reset(new StderrLogger(level));
 }
 
 void RepairCommand::DoCommand() {

tools/ldb_cmd_impl.h

@@ -549,6 +549,12 @@ class RepairCommand : public LDBCommand {
   virtual void OverrideBaseOptions() override;
 
   static void Help(std::string& ret);
+
+ protected:
+  bool verbose_;
+
+ private:
+  static const std::string ARG_VERBOSE;
 };
 
 class BackupableCommand : public LDBCommand {