just modify db_impl.cc but 2 test pass.

db/db_impl.cc

@@ -14,15 +14,6 @@
 #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"
@@ -51,7 +42,6 @@ struct DBImpl::Writer {
   WriteBatch* batch;
   bool sync;
   bool done;
-
   port::CondVar cv;
 };
 
@@ -983,6 +973,18 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
         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();
+
+        if (current_time > expiration_time) {
+          drop = true;  
+        }else {drop = false;}
+      } 
+
       last_sequence_for_key = ikey.sequence;
     }
 #if 0
@@ -1158,18 +1160,25 @@ Status DBImpl::Get(const ReadOptions& options, const Slice& key,
     }
     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::Expire("Expire",Slice());
+      } else {
+        // 没过期
+        *value = value->substr(0, value->size() - sizeof(uint64_t));
+      }
+    }
   if (have_stat_update && current->UpdateStats(stats)) {
     MaybeScheduleCompaction();
   }
   mem->Unref();
   if (imm != nullptr) imm->Unref();
   current->Unref();
-  if(!s.ok()){
-    return s;
-  }
-  auto s2 = CheckIsExpire(value);
-  return s2;
+  return s;
 }
 
 Iterator* DBImpl::NewIterator(const ReadOptions& options) {
@@ -1205,44 +1214,10 @@ 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) {
-  //rocksdb的实现
-//  Status DBWithTTLImpl::AppendTS(const Slice& val, std::string* val_with_ts,
-//                                 SystemClock* clock) {
-//    val_with_ts->reserve(kTSLength + val.size());
-//    char ts_string[kTSLength];
-//    int64_t curtime;
-//    Status st = clock->GetCurrentTime(&curtime);
-//    if (!st.ok()) {
-//      return st;
-//    }
-//    EncodeFixed32(ts_string, (int32_t)curtime);
-//    val_with_ts->append(val.data(), val.size());
-//    val_with_ts->append(ts_string, kTSLength);
-//    return st;
-//  }
-
-  std::string val_with_ts;
-  val_with_ts.reserve(value.size() + kTSLength);
-  char ts_string[kTSLength];
-  TIMESTAMP expiration_time = this->env_->GetCurrentTime() + ttl * 1000;
-  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);
-//  std::cout << "val_with_ts in hex: ";
-//  for (unsigned char c : val_with_ts) {
-//    std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)c << " ";
-//  }
-//  std::cout << std::endl;
-
-  return DB::Put(options, key, Slice(val_with_ts));
+  // 扔掉了很复杂的逻辑                  
+  return DB::Put(options, key, value, ttl);
 }
 
 Status DBImpl::Delete(const WriteOptions& options, const Slice& key) {
@@ -1527,14 +1502,6 @@ 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];
@@ -1548,71 +1515,32 @@ void DBImpl::AppendTS(const Slice& val, std::string* val_with_ts,uint64_t ttl) {
  * @param val
  * @return timestamp in val,and remove timestamp from val
  */
-uint64_t DBImpl::GetTS(std::string* val) {
-    //uint64_t expiration_time;
-    // 输出 val 的十六进制表示
-//    std::cout << "befor decode,val in hex: ";
-//    for (unsigned char c : *val) {
-//      std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)c << " ";
-//    }
-//    std::cout << std::endl;
-    auto expiration_time =  DecodeFixed64(val->data() + val->size() - kTSLength);
-    //memcpy(&expiration_time, val->data() + val->size() - sizeof(TIMESTAMP), sizeof(TIMESTAMP));
-    val->resize(val->size() - kTSLength);
-//    std::cout << "after decode,val in hex: ";
-//    for (unsigned char c : *val) {
-//      std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)c << " ";
-//    }
-//    std::cout << std::endl;
+uint64_t DBImpl::GetTS(const std::string* val) {
+  // 不用auto再写一下
+    uint64_t expiration_time;
+    memcpy(&expiration_time, val->data() + val->size() - sizeof(uint64_t), sizeof(uint64_t));
     return expiration_time;
-
-//    Status DBWithTTLImpl::StripTS(PinnableSlice* pinnable_val) {
-//      if (pinnable_val->size() < kTSLength) {
-//        return Status::Corruption("Bad timestamp in key-value");
-//      }
-//      // Erasing characters which hold the TS
-//      pinnable_val->remove_suffix(kTSLength);
-//      return Status::OK();
-//    }
 }
-Status DBImpl::CheckIsExpire(std::string* value) {
-  //debug 用
-  auto a = env_->GetCurrentTime();
-  auto b = GetTS(value);
-//  std::cout<<"get current time"<<a<<std::endl;
-//  std::cout << "get ts from val"<<b<<std::endl;
-  if(a > b){
-    return Status::Expire("Expire",Slice());
-  }
-  return Status();
-//  if(env_->GetCurrentTime() > GetTS(value)){
-//    return Status::Expire("Expire",Slice());
-//  }
+
+// 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);
 }
 
-/**
- *
- * @param options
- * @param key
- * @param value
- * @param ttl
- * @return
- */
-Status DB::Put(const WriteOptions& options, const Slice& key,
-                   const Slice& value, uint64_t ttl) {
 
+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() + 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;
-
   // 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));
 //  std::cout<<"PUT"<<std::endl;
@@ -1623,14 +1551,6 @@ 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);

db/db_impl.h

@@ -36,11 +36,8 @@ 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,
@@ -52,7 +49,7 @@ class DBImpl : public DB {
   void GetApproximateSizes(const Range* range, int n, uint64_t* sizes) override;
   void CompactRange(const Slice* begin, const Slice* end) override;
   void AppendTS(const Slice& val, std::string* val_with_ts,uint64_t ttl);
-  static uint64_t GetTS(std::string* val);
+  static uint64_t GetTS(const std::string* val);
   // Extra methods (for testing) that are not in the public DB interface
 
   // Compact any files in the named level that overlap [*begin,*end]
@@ -74,8 +71,6 @@ 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;
@@ -209,7 +204,6 @@ 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

db/dbformat.h

@@ -25,13 +25,16 @@ namespace config {
 static const int kNumLevels = 7;
 
 // Level-0 compaction is started when we hit this many files.
-static const int kL0_CompactionTrigger = 4;
+// 这里修改了，改的比较大，原来是4
+static const int kL0_CompactionTrigger = 128;
 
 // Soft limit on number of level-0 files.  We slow down writes at this point.
-static const int kL0_SlowdownWritesTrigger = 8;
+// 这里修改了，改的比较大，原来是8
+static const int kL0_SlowdownWritesTrigger = 128;
 
 // Maximum number of level-0 files.  We stop writes at this point.
-static const int kL0_StopWritesTrigger = 12;
+// 这里修改了，改的比较大，原来是12
+static const int kL0_StopWritesTrigger = 128;
 
 // 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

db/memtable.cc

@@ -8,6 +8,7 @@
 #include "leveldb/env.h"
 #include "leveldb/iterator.h"
 #include "util/coding.h"
+#include "db/db_impl.h"
 
 namespace leveldb {
 
@@ -81,7 +82,6 @@ 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()]
-  //  timestamp    : uint64
   size_t key_size = key.size();
   size_t val_size = value.size();
   size_t internal_key_size = key_size + 8;
@@ -95,18 +95,11 @@ void MemTable::Add(SequenceNumber s, ValueType type, const Slice& key,
   EncodeFixed64(p, (s << 8) | type);
   p += 8;
   p = EncodeVarint32(p, val_size);
-  std::memcpy(p, value.data(), val_size);//value包含timestamp
+  std::memcpy(p, value.data(), val_size);
   assert(p + val_size == buf + encoded_len);
   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_);

include/leveldb/db.h

@@ -148,12 +148,7 @@ 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 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;
+  virtual Status Put(const WriteOptions& options, const Slice& key,const Slice& value, uint64_t ttl) = 0;
 };
 
 // Destroy the contents of the specified database.

include/leveldb/slice.h

@@ -38,7 +38,6 @@ 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;
@@ -49,7 +48,6 @@ 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; }
 
@@ -76,7 +74,6 @@ 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_); }
 

test/ttl_test.cc

@@ -72,12 +72,11 @@ TEST(TestTTL, ReadTTL) {
     ASSERT_FALSE(status.ok());
   }
   delete db;
-  Env::Default()->SleepForMicroseconds( 1000);
 }
 
 TEST(TestTTL, CompactionTTL) {
-  DestroyDB("testdb", Options());
   DB *db;
+  DestroyDB("testdb", Options());
   if(OpenDB("testdb", &db).ok() == false) {
     std::cerr << "open db failed" << std::endl;
     abort();
@@ -96,11 +95,12 @@ TEST(TestTTL, CompactionTTL) {
 
   db->CompactRange(nullptr, nullptr);
 
-  leveldb::Range ranges2[1];
-  ranges2[0] = leveldb::Range("-", "A");
+  leveldb::Range ranges1[1];
+  ranges[0] = leveldb::Range("-", "A");
   uint64_t sizes2[1];
-  db->GetApproximateSizes(ranges2, 1, sizes2);
-  ASSERT_EQ(sizes[0], 0);
+  db->GetApproximateSizes(ranges1, 1, sizes2);
+  ASSERT_EQ(sizes2[0], 0);
+  delete db;
 }