From 8f1861462b27727dfc5b2c4687112108e6ba88eb Mon Sep 17 00:00:00 2001
From: leveldb Team <no-reply@google.com>
Date: Tue, 12 Jan 2021 21:08:52 +0000
Subject: [PATCH] Sync MANIFEST before closing in db_impl when creating a new
 DB. Add logging with debugging information when failing to load a version
 set.

PiperOrigin-RevId: 351432332
---
 db/db_impl.cc     | 5 +++++
 db/version_set.cc | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/db/db_impl.cc b/db/db_impl.cc
index 59b834f..1a4e459 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -197,6 +197,9 @@ Status DBImpl::NewDB() {
     new_db.EncodeTo(&record);
     s = log.AddRecord(record);
     if (s.ok()) {
+      s = file->Sync();
+    }
+    if (s.ok()) {
       s = file->Close();
     }
   }
@@ -301,6 +304,8 @@ Status DBImpl::Recover(VersionEdit* edit, bool* save_manifest) {
 
   if (!env_->FileExists(CurrentFileName(dbname_))) {
     if (options_.create_if_missing) {
+      Log(options_.info_log, "Creating DB %s since it was missing.",
+          dbname_.c_str());
       s = NewDB();
       if (!s.ok()) {
         return s;
diff --git a/db/version_set.cc b/db/version_set.cc
index a459587..1963353 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -898,6 +898,7 @@ Status VersionSet::Recover(bool* save_manifest) {
   uint64_t log_number = 0;
   uint64_t prev_log_number = 0;
   Builder builder(this, current_);
+  int read_records = 0;
 
   {
     LogReporter reporter;
@@ -907,6 +908,7 @@ Status VersionSet::Recover(bool* save_manifest) {
     Slice record;
     std::string scratch;
     while (reader.ReadRecord(&record, &scratch) && s.ok()) {
+      ++read_records;
       VersionEdit edit;
       s = edit.DecodeFrom(record);
       if (s.ok()) {
@@ -981,6 +983,10 @@ Status VersionSet::Recover(bool* save_manifest) {
     } else {
       *save_manifest = true;
     }
+  } else {
+    std::string error = s.ToString();
+    Log(options_->info_log, "Error recovering version set with %d records: %s",
+        read_records, error.c_str());
   }
 
   return s;