From 74c80876cd7c25907b07c73c72032e8939252b28 Mon Sep 17 00:00:00 2001
From: xhguo <10211900416@stu.ecnu.edu.cn>
Date: Thu, 7 Nov 2024 06:48:38 +0800
Subject: [PATCH] merge lzj_version and little modification

---
 README.md                |   6 +-
 db/builder.cc            |  24 +++++--
 db/db_impl.cc            | 169 +++++++++++++++++++++++++++++++----------------
 db/db_impl.h             |  10 ++-
 db/dbformat.h            |   9 +--
 db/memtable.cc           |  26 +++-----
 db/version_edit.cc       |   9 +++
 db/version_edit.h        |  20 +++++-
 db/version_set.cc        |  21 +++++-
 db/version_set.h         |   6 +-
 include/leveldb/db.h     |   7 +-
 include/leveldb/slice.h  |   3 +
 include/leveldb/status.h |   1 +
 table/block.cc           |  22 +-----
 test/simple_test.cc      |   2 +-
 test/ttl_test.cc         |  13 ++--
 util/coding.cc           |   7 ++
 17 files changed, 229 insertions(+), 126 deletions(-)

diff --git a/README.md b/README.md
index 2e2c298..099d1f5 100644
--- a/README.md
+++ b/README.md
@@ -2,4 +2,8 @@
 
 LevelDB project 1
 
-**本仓库提供TTL基本的测试用例**
\ No newline at end of file
+10225501460 林子骥
+
+10211900416 郭夏辉
+
+如果出现open db failed，可能是运行地太慢了，请酌情调高ttl_test.cc中ttl的值。
\ No newline at end of file
diff --git a/db/builder.cc b/db/builder.cc
index 4c6d802..a7dc15a 100644
--- a/db/builder.cc
+++ b/db/builder.cc
@@ -14,6 +14,16 @@
 
 namespace leveldb {
 
+/**
+ * description:目的，将内存中的数据写入一个新的 SSTable 文件
+ * @param dbname
+ * @param env
+ * @param options
+ * @param table_cache
+ * @param iter
+ * @param meta ：存储新sstable的相关元数据
+ * @return
+ */
 Status BuildTable(const std::string& dbname, Env* env, const Options& options,
                   TableCache* table_cache, Iterator* iter, FileMetaData* meta) {
   Status s;
@@ -21,6 +31,7 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
   iter->SeekToFirst();
 
   std::string fname = TableFileName(dbname, meta->number);
+
   if (iter->Valid()) {
     WritableFile* file;
     s = env->NewWritableFile(fname, &file);
@@ -30,16 +41,17 @@ Status BuildTable(const std::string& dbname, Env* env, const Options& options,
 
     TableBuilder* builder = new TableBuilder(options, file);
     meta->smallest.DecodeFrom(iter->key());//这里是internal_key
-//    auto tmp_ts = DecodeFixed64(iter->value().data() + iter->value().size() - kTSLength);
-//    meta->oldest_ts = tmp_ts;
-//    meta->newer_ts = tmp_ts;
+    auto tmp_ts = DecodeFixed64(iter->value().data() + iter->value().size() - kTSLength);
+    meta->oldest_ts = tmp_ts;
+    meta->newer_ts = tmp_ts;
+
     Slice key;
     for (; iter->Valid(); iter->Next()) {
       key = iter->key();
       builder->Add(key, iter->value());
-//      tmp_ts = DecodeFixed64(iter->value().data() + iter->value().size() - kTSLength);
-//      meta->oldest_ts = meta->oldest_ts > tmp_ts ? tmp_ts : meta->oldest_ts;
-//      meta->newer_ts = meta->newer_ts > tmp_ts ? meta->newer_ts : tmp_ts;
+      tmp_ts = DecodeFixed64(iter->value().data() + iter->value().size() - kTSLength);
+      meta->oldest_ts = meta->oldest_ts > tmp_ts ? tmp_ts : meta->oldest_ts;
+      meta->newer_ts = meta->newer_ts > tmp_ts ? meta->newer_ts : tmp_ts;
     }
     if (!key.empty()) {
       meta->largest.DecodeFrom(key);
diff --git a/db/db_impl.cc b/db/db_impl.cc
index b117cb1..751f86f 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -14,6 +14,15 @@
 #include "db/table_cache.h"
 #include "db/version_set.h"
 #include "db/write_batch_internal.h"
+#include <algorithm>
+#include <atomic>
+#include <cstdint>
+#include <cstdio>
+#include <iomanip>
+#include <iostream>
+#include <set>
+#include <string>
+#include <vector>
 
 #include "leveldb/db.h"
 #include "leveldb/env.h"
@@ -42,6 +51,7 @@ struct DBImpl::Writer {
   WriteBatch* batch;
   bool sync;
   bool done;
+
   port::CondVar cv;
 };
 
@@ -51,6 +61,7 @@ struct DBImpl::CompactionState {
     uint64_t number;
     uint64_t file_size;
     InternalKey smallest, largest;
+    TIMESTAMP old_ts,new_ts;
   };
 
   Output* current_output() { return &outputs[outputs.size() - 1]; }
@@ -526,11 +537,15 @@ Status DBImpl::WriteLevel0Table(MemTable* mem, VersionEdit* edit,
   if (s.ok() && meta.file_size > 0) {
     const Slice min_user_key = meta.smallest.user_key();
     const Slice max_user_key = meta.largest.user_key();
+    const TIMESTAMP new_ts = meta.newer_ts;
+    const TIMESTAMP old_ts = meta.oldest_ts;
     if (base != nullptr) {
-      level = base->PickLevelForMemTableOutput(min_user_key, max_user_key);
+      level = base->PickLevelForMemTableOutput(min_user_key, max_user_key);// TODO :基于timestamp和size和seek的新的选择规则
     }
+//    edit->AddFile(level, meta.number, meta.file_size, meta.smallest,
+//                  meta.largest);
     edit->AddFile(level, meta.number, meta.file_size, meta.smallest,
-                  meta.largest);
+                  meta.largest,old_ts,new_ts);
   }
 
   CompactionStats stats;
@@ -619,7 +634,7 @@ void DBImpl::TEST_CompactRange(int level, const Slice* begin,
          bg_error_.ok()) {
     if (manual_compaction_ == nullptr) {  // Idle
       manual_compaction_ = &manual;
-      MaybeScheduleCompaction();//有可能寻址过多，导致allow_seek为0，触发合并。
+      MaybeScheduleCompaction();
     } else {  // Running either my compaction or another compaction.
       background_work_finished_signal_.Wait();
     }
@@ -734,8 +749,10 @@ void DBImpl::BackgroundCompaction() {
     assert(c->num_input_files(0) == 1);
     FileMetaData* f = c->input(0, 0);
     c->edit()->RemoveFile(c->level(), f->number);
+//    c->edit()->AddFile(c->level() + 1, f->number, f->file_size, f->smallest,
+//                       f->largest);
     c->edit()->AddFile(c->level() + 1, f->number, f->file_size, f->smallest,
-                       f->largest);
+                       f->largest,f->oldest_ts,f->newer_ts);
     status = versions_->LogAndApply(c->edit(), &mutex_);
     if (!status.ok()) {
       RecordBackgroundError(status);
@@ -747,7 +764,7 @@ void DBImpl::BackgroundCompaction() {
         status.ToString().c_str(), versions_->LevelSummary(&tmp));
   } else {
     CompactionState* compact = new CompactionState(c);
-    status = DoCompactionWork(compact);
+    status = DoCompactionWork(compact);//
     if (!status.ok()) {
       RecordBackgroundError(status);
     }
@@ -809,6 +826,8 @@ Status DBImpl::OpenCompactionOutputFile(CompactionState* compact) {
     out.number = file_number;
     out.smallest.Clear();
     out.largest.Clear();
+    out.old_ts = UINT64_MAX;
+    out.new_ts = 0;
     compact->outputs.push_back(out);
     mutex_.Unlock();
   }
@@ -883,8 +902,10 @@ Status DBImpl::InstallCompactionResults(CompactionState* compact) {
   const int level = compact->compaction->level();
   for (size_t i = 0; i < compact->outputs.size(); i++) {
     const CompactionState::Output& out = compact->outputs[i];
+//    compact->compaction->edit()->AddFile(level + 1, out.number, out.file_size,
+//                                         out.smallest, out.largest);
     compact->compaction->edit()->AddFile(level + 1, out.number, out.file_size,
-                                         out.smallest, out.largest);
+                                         out.smallest, out.largest,out.old_ts,out.new_ts);
   }
   return versions_->LogAndApply(compact->compaction->edit(), &mutex_);
 }
@@ -908,13 +929,13 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
   }
 
   Iterator* input = versions_->MakeInputIterator(compact->compaction);
-
   // Release mutex while we're actually doing the compaction work
   mutex_.Unlock();
 
   input->SeekToFirst();
   Status status;
   ParsedInternalKey ikey;
+  TIMESTAMP ts = 0;
   std::string current_user_key;
   bool has_current_user_key = false;
   SequenceNumber last_sequence_for_key = kMaxSequenceNumber;
@@ -940,7 +961,7 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
         break;
       }
     }
-
+    //auto a = DecodeFixed64(input->value().data() + input->value().size() - kTSLength);//debug
     // Handle key/value, add to state, etc.
     bool drop = false;
     if (!ParseInternalKey(key, &ikey)) {
@@ -972,19 +993,10 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
         //     few iterations of this loop (by rule (A) above).
         // Therefore this deletion marker is obsolete and can be dropped.
         drop = true;
-      }
-
-      Slice value = input->value();
-      if (value.size() >= sizeof(uint64_t)) {
-        const char* ptr = value.data();
-        std::string temp_str(value.data(), value.size());
-        uint64_t expiration_time = DBImpl::GetTS(&temp_str);
-        uint64_t current_time = env_->GetCurrentTime();
+      }else if((ts = DecodeFixed64(input->value().data() + input->value().size() - kTSLength)) < env_->NowMicros()){
 
-        if (current_time > expiration_time) {
-          drop = true;  
-        }else {drop = false;}
-      } 
+        drop = true;
+      }
 
       last_sequence_for_key = ikey.sequence;
     }
@@ -1010,6 +1022,10 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
         compact->current_output()->smallest.DecodeFrom(key);
       }
       compact->current_output()->largest.DecodeFrom(key);
+      assert(ts != 0);
+      //auto b = compact->current_output()->old_ts;
+      compact->current_output()->old_ts = std::min(compact->current_output()->old_ts,ts);
+      compact->current_output()->new_ts = std::max(compact->current_output()->new_ts,ts);
       compact->builder->Add(key, input->value());
 
       // Close output file if it is big enough
@@ -1156,29 +1172,29 @@ Status DBImpl::Get(const ReadOptions& options, const Slice& key,
     } else if (imm != nullptr && imm->Get(lkey, value, &s)) {
       // Done
     } else {
+      stats.now_ts = this->env_->NowMicros();
       s = current->Get(options, lkey, value, &stats);
       have_stat_update = true;
     }
     mutex_.Lock();
   }
-  if (s.ok()) {
-      // 直接在这里判断是否过期
-      auto t1 = env_->GetCurrentTime();
-      auto t2 = GetTS(value);
-      if(t1 >= t2){
-        // 过期
-        s = Status::NotFound("NotFound",Slice());
-      } else {
-        // 没过期
-        *value = value->substr(0, value->size() - sizeof(uint64_t));
-      }
-    }
-  if (have_stat_update && current->UpdateStats(stats)) {
-    MaybeScheduleCompaction();
+  if(s.ok()){
+    s = CheckIsExpire(value);
+  }
+  if (have_stat_update && current->UpdateStats(stats,s.IsExpire())) {
+    MaybeScheduleCompaction();//有可能寻址过多，导致allow_seek为0，触发合并。
   }
   mem->Unref();
   if (imm != nullptr) imm->Unref();
+
   current->Unref();
+//  if(!s.ok()){
+//    return s;
+//  }
+//  auto s2 = CheckIsExpire(value);
+//  if(!s2.ok()){
+//    current->UpdateStats(stats);
+//  }
   return s;
 }
 
@@ -1215,10 +1231,23 @@ void DBImpl::ReleaseSnapshot(const Snapshot* snapshot) {
 Status DBImpl::Put(const WriteOptions& o, const Slice& key, const Slice& val) {
   return DB::Put(o, key, val);
 }
+
+
 Status DBImpl::Put(const WriteOptions& options, const Slice& key,
                    const Slice& value, uint64_t ttl) {
-  // 扔掉了很复杂的逻辑                  
-  return DB::Put(options, key, value, ttl);
+
+  std::string val_with_ts;
+  val_with_ts.reserve(value.size() + kTSLength);
+  char ts_string[kTSLength];
+  TIMESTAMP expiration_time = this->env_->NowMicros() + ttl * 1000000;
+  EncodeFixed64(ts_string,expiration_time);
+  //assert(sizeof(expiration_time) == sizeof(TIMESTAMP ));
+  // 追加原始 value 到 val_with_ts
+  val_with_ts.append(value.data(), value.size());
+
+  // 将 expiration_time 追加到 val_with_ts
+  val_with_ts.append(ts_string,kTSLength);
+  return DB::Put(options, key, Slice(val_with_ts));
 }
 
 Status DBImpl::Delete(const WriteOptions& options, const Slice& key) {
@@ -1503,6 +1532,14 @@ void DBImpl::GetApproximateSizes(const Range* range, int n, uint64_t* sizes) {
   }
   v->Unref();
 }
+
+
+/**
+ *
+ * @param val
+ * @param val_with_ts 在val后面连接上预计超时的timestamp
+ * @param ttl 存活时间
+ */
 void DBImpl::AppendTS(const Slice& val, std::string* val_with_ts,uint64_t ttl) {
   val_with_ts->reserve(kTSLength + val.size());
   char ts_string[kTSLength];
@@ -1517,41 +1554,51 @@ void DBImpl::AppendTS(const Slice& val, std::string* val_with_ts,uint64_t ttl) {
  * @return timestamp in val,and remove timestamp from val
  */
 uint64_t DBImpl::GetTS(std::string* val) {
-  // 不用auto再写一下 老逻辑：
-    // uint64_t expiration_time;
-    // memcpy(&expiration_time, val->data() + val->size() - sizeof(uint64_t), sizeof(uint64_t));
-    // return expiration_time;
-  // 新逻辑：
-  auto expiration_time =  DecodeFixed64(val->data() + val->size() - kTSLength);
-  val->resize(val->size() - kTSLength);
-  return expiration_time;
-}
 
-// Default implementations of convenience methods that subclasses of DB
-// can call if they wish
-Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) {
-  WriteBatch batch;
-  batch.Put(key, value);
-  return Write(opt, &batch);
+    auto expiration_time =  DecodeFixed64(val->data() + val->size() - kTSLength);
+
+    val->resize(val->size() - kTSLength);
+
+    return expiration_time;
+
 }
+Status DBImpl::CheckIsExpire(std::string* value) {
+  //debug 用
+  auto a = env_->NowMicros();
+  auto b = GetTS(value);
 
+  if(a > b){
+    return Status::Expire("Expire",Slice());
+  }
+  return Status();
 
-Status DB::Put(const WriteOptions& options, const Slice& key, 
+}
+
+/**
+ *
+ * @param options
+ * @param key
+ * @param value
+ * @param ttl
+ * @return
+ */
+Status DB::Put(const WriteOptions& options, const Slice& key,
                    const Slice& value, uint64_t ttl) {
+
   // 将 value 和 expiration_time 合并到一起，形成带 TTL 的 value
   std::string val_with_ts;
-  val_with_ts.reserve(value.size() + kTSLength);
+
+  val_with_ts.reserve(value.size() + sizeof(uint64_t));
+
   uint64_t expiration_time = std::chrono::duration_cast<std::chrono::milliseconds>(
                                  std::chrono::system_clock::now().time_since_epoch())
                                  .count() + ttl * 1000;
 
-  char ts_string[kTSLength];
-  EncodeFixed64(ts_string, expiration_time);
   // 追加原始 value 到 val_with_ts
   val_with_ts.append(value.data(), value.size());
+
   // 将 expiration_time 追加到 val_with_ts
-  // val_with_ts.append(reinterpret_cast<const char*>(&expiration_time), sizeof(expiration_time));
-  val_with_ts.append(ts_string, kTSLength);
+  val_with_ts.append(reinterpret_cast<const char*>(&expiration_time), sizeof(expiration_time));
 //  std::cout<<"PUT"<<std::endl;
 //  std::cout << "timestamp: " << expiration_time << std::endl;
   //"a\323='\277\222\001\000"
@@ -1560,6 +1607,14 @@ Status DB::Put(const WriteOptions& options, const Slice& key,
   return Write(options, &batch);
 }
 
+// Default implementations of convenience methods that subclasses of DB
+// can call if they wish
+Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) {
+  WriteBatch batch;
+  batch.Put(key, value);
+  return Write(opt, &batch);
+}
+
 Status DB::Delete(const WriteOptions& opt, const Slice& key) {
   WriteBatch batch;
   batch.Delete(key);
diff --git a/db/db_impl.h b/db/db_impl.h
index 5c5b2f5..7cb4bdd 100644
--- a/db/db_impl.h
+++ b/db/db_impl.h
@@ -36,8 +36,11 @@ class DBImpl : public DB {
   ~DBImpl() override;
 
   // Implementations of the DB interface
-  Status Put(const WriteOptions&, const Slice& key,const Slice& value) override;
-  Status Put(const WriteOptions& options, const Slice& key, const Slice& value,uint64_t ttl) override;
+  Status Put(const WriteOptions&, const Slice& key,
+             const Slice& value) override;
+
+  Status Put(const WriteOptions& options, const Slice& key, const Slice& value,
+             uint64_t ttl) override;
   Status Delete(const WriteOptions&, const Slice& key) override;
   Status Write(const WriteOptions& options, WriteBatch* updates) override;
   Status Get(const ReadOptions& options, const Slice& key,
@@ -71,6 +74,8 @@ class DBImpl : public DB {
   // Samples are taken approximately once every config::kReadBytesPeriod
   // bytes.
   void RecordReadSample(Slice key);
+//  Status Write(const WriteOptions& options, WriteBatch* updates,
+//               uint64_t ttl) override;
 
  private:
   friend class DB;
@@ -204,6 +209,7 @@ class DBImpl : public DB {
   Status bg_error_ GUARDED_BY(mutex_);
 
   CompactionStats stats_[config::kNumLevels] GUARDED_BY(mutex_);
+  Status CheckIsExpire(std::string* value);
 };
 
 // Sanitize db options.  The caller should delete result.info_log if
diff --git a/db/dbformat.h b/db/dbformat.h
index 56f8178..6454c92 100644
--- a/db/dbformat.h
+++ b/db/dbformat.h
@@ -25,16 +25,13 @@ namespace config {
 static const int kNumLevels = 7;
 
 // Level-0 compaction is started when we hit this many files.
-// 这里修改了，改的比较大，原来是4
-static const int kL0_CompactionTrigger = 64;
+static const int kL0_CompactionTrigger = 4;
 
 // Soft limit on number of level-0 files.  We slow down writes at this point.
-// 这里修改了，改的比较大，原来是8
-static const int kL0_SlowdownWritesTrigger = 64;
+static const int kL0_SlowdownWritesTrigger = 8;
 
 // Maximum number of level-0 files.  We stop writes at this point.
-// 这里修改了，改的比较大，原来是12
-static const int kL0_StopWritesTrigger = 64;
+static const int kL0_StopWritesTrigger = 12;
 
 // Maximum level to which a new compacted memtable is pushed if it
 // does not create overlap.  We try to push to level 2 to avoid the
diff --git a/db/memtable.cc b/db/memtable.cc
index c561523..8115557 100644
--- a/db/memtable.cc
+++ b/db/memtable.cc
@@ -8,7 +8,6 @@
 #include "leveldb/env.h"
 #include "leveldb/iterator.h"
 #include "util/coding.h"
-#include "db/db_impl.h"
 
 namespace leveldb {
 
@@ -82,6 +81,7 @@ void MemTable::Add(SequenceNumber s, ValueType type, const Slice& key,
   //  tag          : uint64((sequence << 8) | type)
   //  value_size   : varint32 of value.size()
   //  value bytes  : char[value.size()],[real_value,timestamp(uint64)]
+  //
   size_t key_size = key.size();
   size_t val_size = value.size();
   size_t internal_key_size = key_size + 8;
@@ -100,6 +100,13 @@ void MemTable::Add(SequenceNumber s, ValueType type, const Slice& key,
   table_.Insert(buf);
 }
 
+/**
+ * @descrption: ttl问题场景：一个key，多个版本，其ttl的相对大小于版本号的相对大小不同
+ * @param key
+ * @param value
+ * @param s
+ * @return
+ */
 bool MemTable::Get(const LookupKey& key, std::string* value, Status* s) {
   Slice memkey = key.memtable_key();
   Table::Iterator iter(&table_);
@@ -125,23 +132,6 @@ bool MemTable::Get(const LookupKey& key, std::string* value, Status* s) {
         case kTypeValue: {
           Slice v = GetLengthPrefixedSlice(key_ptr + key_length);
           value->assign(v.data(), v.size());
-
-          // 这里新加了一些逻辑
-          if (value->size() >= sizeof(uint64_t)){
-            const char* ptr = value->data();
-            std::string temp_str(value->data(), value->size());
-            uint64_t expiration_time = DBImpl::GetTS(&temp_str);
-            uint64_t current_time = std::chrono::duration_cast<std::chrono::milliseconds>(
-              std::chrono::system_clock::now().time_since_epoch())
-              .count();
-
-            if (current_time > expiration_time) {
-              *s = Status::NotFound("NotFound",Slice());
-            }else {
-              *value = value->substr(0, value->size() - sizeof(uint64_t));
-            }
-          }
-          
           return true;
         }
         case kTypeDeletion:
diff --git a/db/version_edit.cc b/db/version_edit.cc
index 356ce88..7a19391 100644
--- a/db/version_edit.cc
+++ b/db/version_edit.cc
@@ -81,6 +81,8 @@ void VersionEdit::EncodeTo(std::string* dst) const {
     PutVarint64(dst, f.file_size);
     PutLengthPrefixedSlice(dst, f.smallest.Encode());
     PutLengthPrefixedSlice(dst, f.largest.Encode());
+    PutFixed64(dst,f.oldest_ts);
+    PutFixed64(dst,f.newer_ts);
   }
 }
 
@@ -180,6 +182,9 @@ Status VersionEdit::DecodeFrom(const Slice& src) {
             GetVarint64(&input, &f.file_size) &&
             GetInternalKey(&input, &f.smallest) &&
             GetInternalKey(&input, &f.largest)) {
+          f.newer_ts = DecodeFixed64(input.data());
+          f.oldest_ts = DecodeFixed64(input.data() + kTSLength);
+          input.remove_prefix(2 * kTSLength);
           new_files_.push_back(std::make_pair(level, f));
         } else {
           msg = "new-file entry";
@@ -250,6 +255,10 @@ std::string VersionEdit::DebugString() const {
     r.append(f.smallest.DebugString());
     r.append(" .. ");
     r.append(f.largest.DebugString());
+    r.append("  ");
+    AppendNumberTo(&r,f.oldest_ts);
+    r.append("..");
+    AppendNumberTo(&r,f.newer_ts);
   }
   r.append("\n}\n");
   return r;
diff --git a/db/version_edit.h b/db/version_edit.h
index 137b4b1..2c776c1 100644
--- a/db/version_edit.h
+++ b/db/version_edit.h
@@ -16,7 +16,7 @@ namespace leveldb {
 class VersionSet;
 
 struct FileMetaData {
-  FileMetaData() : refs(0), allowed_seeks(1 << 30), file_size(0) {}
+  FileMetaData() : refs(0), allowed_seeks(1 << 30), file_size(0),oldest_ts(UINT64_MAX),newer_ts(0) {}
 
   int refs;
   int allowed_seeks;  // Seeks allowed until compaction
@@ -24,6 +24,10 @@ struct FileMetaData {
   uint64_t file_size;    // File size in bytes
   InternalKey smallest;  // Smallest internal key served by table
   InternalKey largest;   // Largest internal key served by table
+  TIMESTAMP oldest_ts;
+  TIMESTAMP newer_ts;
+
+
 };
 
 class VersionEdit {
@@ -69,6 +73,20 @@ class VersionEdit {
     f.largest = largest;
     new_files_.push_back(std::make_pair(level, f));
   }
+  void AddFile(int level, uint64_t file, uint64_t file_size,
+               const InternalKey& smallest, const InternalKey& largest,const TIMESTAMP old_ts,const TIMESTAMP new_ts) {
+    FileMetaData f;
+    f.number = file;
+    f.file_size = file_size;
+    f.smallest = smallest;
+    f.largest = largest;
+    f.newer_ts = new_ts;
+    f.oldest_ts = old_ts;
+    new_files_.push_back(std::make_pair(level, f));
+
+  }
+
+
 
   // Delete the specified "file" from the specified "level".
   void RemoveFile(int level, uint64_t file) {
diff --git a/db/version_set.cc b/db/version_set.cc
index 81b13e9..b81e29b 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -351,7 +351,7 @@ Status Version::Get(const ReadOptions& options, const LookupKey& k,
       state->last_file_read = f;
       state->last_file_read_level = level;
 
-//      if(state->stats->now_ts > f->newer_ts)return false;
+      if(state->stats->now_ts > f->newer_ts)return false;
       state->s = state->vset->table_cache_->Get(*state->options, f->number,
                                                 f->file_size, state->ikey,
                                                 &state->saver, SaveValue);
@@ -413,6 +413,20 @@ bool Version::UpdateStats(const GetStats& stats) {
   return false;
 }
 
+bool Version::UpdateStats(const GetStats& stats,bool is_expire) {
+  FileMetaData* f = stats.seek_file;
+  if (f != nullptr) {
+    f->allowed_seeks--;
+    if(is_expire)f->allowed_seeks--;
+    if (f->allowed_seeks <= 0 && file_to_compact_ == nullptr) {
+      file_to_compact_ = f;
+      file_to_compact_level_ = stats.seek_file_level;
+      return true;
+    }
+  }
+  return false;
+}
+
 bool Version::RecordReadSample(Slice internal_key) {
   ParsedInternalKey ikey;
   if (!ParseInternalKey(internal_key, &ikey)) {
@@ -821,7 +835,7 @@ Status VersionSet::LogAndApply(VersionEdit* edit, port::Mutex* mu) {
     // Write new record to MANIFEST log
     if (s.ok()) {
       std::string record;
-      edit->EncodeTo(&record);// TODO:修改
+      edit->EncodeTo(&record);
       s = descriptor_log_->AddRecord(record);
       if (s.ok()) {
         s = descriptor_file_->Sync();
@@ -1088,7 +1102,8 @@ Status VersionSet::WriteSnapshot(log::Writer* log) {
     const std::vector<FileMetaData*>& files = current_->files_[level];
     for (size_t i = 0; i < files.size(); i++) {
       const FileMetaData* f = files[i];
-      edit.AddFile(level, f->number, f->file_size, f->smallest, f->largest);
+      //edit.AddFile(level, f->number, f->file_size, f->smallest, f->largest);
+      edit.AddFile(level, f->number, f->file_size, f->smallest, f->largest,f->oldest_ts,f->newer_ts);
     }
   }
 
diff --git a/db/version_set.h b/db/version_set.h
index 7b96986..cfdf7c4 100644
--- a/db/version_set.h
+++ b/db/version_set.h
@@ -80,8 +80,8 @@ class Version {
   // compaction may need to be triggered, false otherwise.
   // REQUIRES: lock is held
   bool UpdateStats(const GetStats& stats);
-
-  // Record a sample of bytes read at the specified internal key.
+  bool UpdateStats(const GetStats& stats,bool is_expire);
+      // Record a sample of bytes read at the specified internal key.
   // Samples are taken approximately once every config::kReadBytesPeriod
   // bytes.  Returns true if a new compaction may need to be triggered.
   // REQUIRES: lock is held
@@ -313,7 +313,7 @@ class VersionSet {
 
   // Per-level key at which the next compaction at that level should start.
   // Either an empty string, or a valid InternalKey.
-  std::string compact_pointer_[config::kNumLevels];
+  std::string compact_pointer_[config::kNumLevels];//会在完成一次压缩操作后进行更新，以确保下一次压缩不会总是从相同的地方
 };
 
 // A Compaction encapsulates information about a compaction.
diff --git a/include/leveldb/db.h b/include/leveldb/db.h
index 4aaed3a..9f48b29 100644
--- a/include/leveldb/db.h
+++ b/include/leveldb/db.h
@@ -148,7 +148,12 @@ class LEVELDB_EXPORT DB {
 
   // ----------------------------For TTL-----------------------------
   // 为当前key设置ttl，过期后自动失效
-  virtual Status Put(const WriteOptions& options, const Slice& key,const Slice& value, uint64_t ttl) = 0;
+  virtual Status Put(const WriteOptions& options, const Slice& key,
+                     const Slice& value, uint64_t ttl) = 0;
+//  virtual Status Write(const WriteOptions& options, WriteBatch* updates,uint64_t ttl) = 0;
+
+//  virtual void AppendTS(const Slice& val, std::string* val_with_ts,uint64_t ttl) = 0;
+//  virtual void AppendTS(const Slice& val, std::string* val_with_ts,uint64_t ttl) = 0;
 };
 
 // Destroy the contents of the specified database.
diff --git a/include/leveldb/slice.h b/include/leveldb/slice.h
index e97223a..1c46be7 100644
--- a/include/leveldb/slice.h
+++ b/include/leveldb/slice.h
@@ -38,6 +38,7 @@ class LEVELDB_EXPORT Slice {
   // Create a slice that refers to s[0,strlen(s)-1]
   Slice(const char* s) : data_(s), size_(strlen(s)) {}
 
+
   // Intentionally copyable.
   Slice(const Slice&) = default;
   Slice& operator=(const Slice&) = default;
@@ -48,6 +49,7 @@ class LEVELDB_EXPORT Slice {
   // Return the length (in bytes) of the referenced data
   size_t size() const { return size_; }
 
+
   // Return true iff the length of the referenced data is zero
   bool empty() const { return size_ == 0; }
 
@@ -74,6 +76,7 @@ class LEVELDB_EXPORT Slice {
     size_ -= n;
   }
 
+
   // Return a string that contains the copy of the referenced data.
   std::string ToString() const { return std::string(data_, size_); }
 
diff --git a/include/leveldb/status.h b/include/leveldb/status.h
index e4943be..9c63d01 100644
--- a/include/leveldb/status.h
+++ b/include/leveldb/status.h
@@ -74,6 +74,7 @@ class LEVELDB_EXPORT Status {
   // Returns true iff the status indicates an InvalidArgument.
   bool IsInvalidArgument() const { return code() == kInvalidArgument; }
 
+  bool IsExpire()const{return code() == kExpire;}
   // Return a string representation of this status suitable for printing.
   // Returns the string "OK" for success.
   std::string ToString() const;
diff --git a/table/block.cc b/table/block.cc
index eae569a..3b15257 100644
--- a/table/block.cc
+++ b/table/block.cc
@@ -220,27 +220,7 @@ class Block::Iter : public Iterator {
       if (!ParseNextKey()) {
         return;
       }
-      if (Compare(key_, target) >= 0) { // 找到了key_
-
-      // 这里新加了一些逻辑
-        std::string value(value_.data(), value_.size());
-        if (value.size() >= sizeof(uint64_t)){
-            const char* ptr = value.data();
-            std::string temp_str(value.data(), value.size());
-            uint64_t expiration_time =  DecodeFixed64((&temp_str)->data() + (&temp_str)->size() - sizeof(uint64_t));
-            (&temp_str)->resize((&temp_str)->size() - sizeof(uint64_t));
-
-            uint64_t current_time = std::chrono::duration_cast<std::chrono::milliseconds>(
-              std::chrono::system_clock::now().time_since_epoch())
-              .count();
-
-            if (current_time > expiration_time) {
-              status_ = Status::NotFound("NotFound",Slice());
-            }else {
-              value_ = value.substr(0, value.size() - sizeof(uint64_t));
-            }
-          }
-
+      if (Compare(key_, target) >= 0) {
         return;
       }
     }
diff --git a/test/simple_test.cc b/test/simple_test.cc
index ec2edfa..3de1f3b 100644
--- a/test/simple_test.cc
+++ b/test/simple_test.cc
@@ -113,7 +113,7 @@ int main() {
   std::string key = std::to_string(key_);
   std::string value(1, 'a');
   db->Put(writeOptions, key, value, ttl);
-  std::cout << "time to alive" << ttl << std::endl;
+  //std::cout << "time to alive" << ttl << std::endl;
 
   ReadOptions readOptions;
   std::string value_read;
diff --git a/test/ttl_test.cc b/test/ttl_test.cc
index 7205e12..521cae8 100644
--- a/test/ttl_test.cc
+++ b/test/ttl_test.cc
@@ -39,13 +39,14 @@ void GetData(DB *db, int size = (1 << 30)) {
     db->Get(readOptions, key, &value);
   }
 }
-
+//
 TEST(TestTTL, ReadTTL) {
   DB *db;
   if(OpenDB("testdb", &db).ok() == false) {
     std::cerr << "open db failed" << std::endl;
     abort();
   }
+  // 如果出现open db fail,请酌情提高这里
   uint64_t ttl = 20;
 
   InsertData(db, ttl);
@@ -72,11 +73,12 @@ TEST(TestTTL, ReadTTL) {
     ASSERT_FALSE(status.ok());
   }
   delete db;
+  Env::Default()->SleepForMicroseconds( 1000);
 }
 
 TEST(TestTTL, CompactionTTL) {
-  DB *db;
   DestroyDB("testdb", Options());
+  DB *db;
   if(OpenDB("testdb", &db).ok() == false) {
     std::cerr << "open db failed" << std::endl;
     abort();
@@ -95,12 +97,11 @@ TEST(TestTTL, CompactionTTL) {
 
   db->CompactRange(nullptr, nullptr);
 
-  leveldb::Range ranges1[1];
-  ranges[0] = leveldb::Range("-", "A");
+  leveldb::Range ranges2[1];
+  ranges2[0] = leveldb::Range("-", "A");
   uint64_t sizes2[1];
-  db->GetApproximateSizes(ranges1, 1, sizes2);
+  db->GetApproximateSizes(ranges2, 1, sizes2);
   ASSERT_EQ(sizes2[0], 0);
-  delete db;
 }
 
 
diff --git a/util/coding.cc b/util/coding.cc
index a8f8af8..cb0ffaf 100644
--- a/util/coding.cc
+++ b/util/coding.cc
@@ -69,6 +69,7 @@ void PutVarint64(std::string* dst, uint64_t v) {
   dst->append(buf, ptr - buf);
 }
 
+
 void PutLengthPrefixedSlice(std::string* dst, const Slice& value) {
   PutVarint32(dst, value.size());
   dst->append(value.data(), value.size());
@@ -142,6 +143,12 @@ bool GetVarint64(Slice* input, uint64_t* value) {
   }
 }
 
+
+//bool GetFixed64(const char* ptr,uint64_t* value){
+//  *value = DecodeFixed64(ptr);
+//  return
+//}
+
 bool GetLengthPrefixedSlice(Slice* input, Slice* result) {
   uint32_t len;
   if (GetVarint32(input, &len) && input->size() >= len) {