From bcd4ccbc33fbc6e17c73eb996b8f45909e880411 Mon Sep 17 00:00:00 2001
From: agiardullo <agiardullo@fb.com>
Date: Tue, 19 Jan 2016 17:24:58 -0800
Subject: [PATCH] Revert D7809

Summary: Revert the functionaility of D7809 (but I'm keeping the logging and test code).  We decided it was dangerous to ignore sync failures based on attempting to read the data written.  The read does not tell us whether the data was synced.

Test Plan: There was no test for the particular functionaility that was reverted.  Keeping the test code from D7809 that tests whether we set the DB to be readonly when paranoid checks are enabled.

Reviewers: rven, yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52989
---
 db/version_set.cc | 60 -----------------------------------------------
 db/version_set.h  |  3 ---
 2 files changed, 63 deletions(-)

diff --git a/db/version_set.cc b/db/version_set.cc
index 193f1076f..519805396 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -2193,27 +2193,6 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
       if (!s.ok()) {
         Log(InfoLogLevel::ERROR_LEVEL, db_options_->info_log,
             "MANIFEST write: %s\n", s.ToString().c_str());
-        bool all_records_in = true;
-        for (auto& e : batch_edits) {
-          std::string record;
-          if (!e->EncodeTo(&record)) {
-            s = Status::Corruption(
-                "Unable to Encode VersionEdit:" + e->DebugString(true));
-            all_records_in = false;
-            break;
-          }
-          if (!ManifestContains(pending_manifest_file_number_, record)) {
-            all_records_in = false;
-            break;
-          }
-        }
-        if (all_records_in) {
-          Log(InfoLogLevel::WARN_LEVEL, db_options_->info_log,
-              "MANIFEST contains log record despite error; advancing to new "
-              "version to prevent mismatch between in-memory and logged state"
-              " If paranoid is set, then the db is now in readonly mode.");
-          s = Status::OK();
-        }
       }
     }
 
@@ -3067,45 +3046,6 @@ Status VersionSet::WriteSnapshot(log::Writer* log) {
   return Status::OK();
 }
 
-// Opens the mainfest file and reads all records
-// till it finds the record we are looking for.
-bool VersionSet::ManifestContains(uint64_t manifest_file_num,
-                                  const std::string& record) const {
-  std::string fname = DescriptorFileName(dbname_, manifest_file_num);
-  Log(InfoLogLevel::INFO_LEVEL, db_options_->info_log,
-      "ManifestContains: checking %s\n", fname.c_str());
-
-  unique_ptr<SequentialFileReader> file_reader;
-  Status s;
-  {
-    unique_ptr<SequentialFile> file;
-    s = env_->NewSequentialFile(fname, &file, env_options_);
-    if (!s.ok()) {
-      Log(InfoLogLevel::INFO_LEVEL, db_options_->info_log,
-          "ManifestContains: %s\n", s.ToString().c_str());
-      Log(InfoLogLevel::INFO_LEVEL, db_options_->info_log,
-          "ManifestContains: is unable to reopen the manifest file  %s",
-          fname.c_str());
-      return false;
-    }
-    file_reader.reset(new SequentialFileReader(std::move(file)));
-  }
-  log::Reader reader(NULL, std::move(file_reader), nullptr,
-                     true /*checksum*/, 0, 0);
-  Slice r;
-  std::string scratch;
-  bool result = false;
-  while (reader.ReadRecord(&r, &scratch)) {
-    if (r == Slice(record)) {
-      result = true;
-      break;
-    }
-  }
-  Log(InfoLogLevel::INFO_LEVEL, db_options_->info_log,
-      "ManifestContains: result = %d\n", result ? 1 : 0);
-  return result;
-}
-
 // TODO(aekmekji): in CompactionJob::GenSubcompactionBoundaries(), this
 // function is called repeatedly with consecutive pairs of slices. For example
 // if the slice list is [a, b, c, d] this function is called with arguments
diff --git a/db/version_set.h b/db/version_set.h
index 2d9d93f6f..097109fd4 100644
--- a/db/version_set.h
+++ b/db/version_set.h
@@ -731,9 +731,6 @@ class VersionSet {
 
   void AppendVersion(ColumnFamilyData* column_family_data, Version* v);
 
-  bool ManifestContains(uint64_t manifest_file_number,
-                        const std::string& record) const;
-
   ColumnFamilyData* CreateColumnFamily(const ColumnFamilyOptions& cf_options,
                                        VersionEdit* edit);