disable size compaction in ldb reduce_levels and added compression and file size parameter to it

Summary:
disable size compaction in ldb reduce_levels, this will avoid compactions rather than the manual comapction,

added --compression=none|snappy|zlib|bzip2 and --file_size= per-file size to ldb reduce_levels command

Test Plan: run ldb

Reviewers: dhruba, MarkCallaghan

Reviewed By: dhruba

CC: sheki, emayanke

Differential Revision: https://reviews.facebook.net/D6597

db/db_bench.cc

@@ -148,7 +148,7 @@ static int FLAGS_target_file_size_base = 2 * 1048576;
 static int FLAGS_target_file_size_multiplier = 1;
 
 // Max bytes for level-1
-static int FLAGS_max_bytes_for_level_base = 10 * 1048576;
+static uint64_t FLAGS_max_bytes_for_level_base = 10 * 1048576;
 
 // A multiplier to compute max bytes for level-N
 static int FLAGS_max_bytes_for_level_multiplier = 10;
@@ -1340,8 +1340,8 @@ int main(int argc, char** argv) {
         &n, &junk) == 1) {
       FLAGS_target_file_size_multiplier = n;
     } else if (
-        sscanf(argv[i], "--max_bytes_for_level_base=%d%c", &n, &junk) == 1) {
-      FLAGS_max_bytes_for_level_base = n;
+        sscanf(argv[i], "--max_bytes_for_level_base=%ld%c", &l, &junk) == 1) {
+      FLAGS_max_bytes_for_level_base = l;
     } else if (sscanf(argv[i], "--max_bytes_for_level_multiplier=%d%c",
         &n, &junk) == 1) {
       FLAGS_max_bytes_for_level_multiplier = n;

db/version_set_reduce_num_levels.cc

@@ -22,6 +22,10 @@ Status VersionSet::ReduceNumberOfLevels(int new_levels, port::Mutex* mu) {
   Version* current_version = current_;
   int current_levels = NumberLevels();
 
+  if (current_levels <= new_levels) {
+    return Status::OK();
+  }
+
   // Make sure there are file only on one level from
   // (new_levels-1) to (current_levels-1)
   int first_nonempty_level = -1;

include/leveldb/options.h

@@ -221,7 +221,7 @@ struct Options {
 
 
   // by default 'max_bytes_for_level_base' is 10MB.
-  int max_bytes_for_level_base;
+  uint64_t max_bytes_for_level_base;
   // by default 'max_bytes_for_level_base' is 10.
   int max_bytes_for_level_multiplier;
 

tools/db_stress.cc

@@ -87,7 +87,7 @@ static int FLAGS_target_file_size_base = 64 * KB;
 static int FLAGS_target_file_size_multiplier = 1;
 
 // Max bytes for level-0
-static int FLAGS_max_bytes_for_level_base = 256 * KB;
+static uint64_t FLAGS_max_bytes_for_level_base = 256 * KB;
 
 // A multiplier to compute max bytes for level-N
 static int FLAGS_max_bytes_for_level_multiplier = 2;
@@ -783,8 +783,8 @@ int main(int argc, char** argv) {
         &n, &junk) == 1) {
       FLAGS_target_file_size_multiplier = n;
     } else if (
-        sscanf(argv[i], "--max_bytes_for_level_base=%d%c", &n, &junk) == 1) {
-      FLAGS_max_bytes_for_level_base = n;
+        sscanf(argv[i], "--max_bytes_for_level_base=%ld%c", &l, &junk) == 1) {
+      FLAGS_max_bytes_for_level_base = l;
     } else if (sscanf(argv[i], "--max_bytes_for_level_multiplier=%d%c",
         &n, &junk) == 1) {
       FLAGS_max_bytes_for_level_multiplier = n;

util/ldb_cmd.cc

@@ -182,18 +182,39 @@ void DBDumper::DoCommand() {
 
 const char* ReduceDBLevels::NEW_LEVLES_ARG = "--new_levels=";
 const char* ReduceDBLevels::PRINT_OLD_LEVELS_ARG = "--print_old_levels";
+const char* ReduceDBLevels::COMPRESSION_TYPE_ARG = "--compression=";
+const char* ReduceDBLevels::FILE_SIZE_ARG = "--file_size=";
 
 ReduceDBLevels::ReduceDBLevels(std::string& db_name,
     std::vector<std::string>& args)
 : LDBCommand(db_name, args),
+  old_levels_(1 << 16),
   new_levels_(-1),
   print_old_levels_(false) {
+  file_size_ = leveldb::Options().target_file_size_base;
+  compression_ = leveldb::Options().compression;
+
   for (unsigned int i = 0; i < args.size(); i++) {
     std::string& arg = args.at(i);
     if (arg.find(NEW_LEVLES_ARG) == 0) {
       new_levels_ = atoi(arg.substr(strlen(NEW_LEVLES_ARG)).c_str());
     } else if (arg.find(PRINT_OLD_LEVELS_ARG) == 0) {
       print_old_levels_ = true;
+    } else if (arg.find(COMPRESSION_TYPE_ARG) == 0) {
+      const char* type = arg.substr(strlen(COMPRESSION_TYPE_ARG)).c_str();
+      if (!strcasecmp(type, "none"))
+        compression_ = leveldb::kNoCompression;
+      else if (!strcasecmp(type, "snappy"))
+        compression_ = leveldb::kSnappyCompression;
+      else if (!strcasecmp(type, "zlib"))
+        compression_ = leveldb::kZlibCompression;
+      else if (!strcasecmp(type, "bzip2"))
+        compression_ = leveldb::kBZip2Compression;
+      else
+        exec_state_ = LDBCommandExecuteResult::FAILED(
+            "Invalid compression arg : " + arg);
+    } else if (arg.find(FILE_SIZE_ARG) == 0) {
+      file_size_ = atoi(arg.substr(strlen(FILE_SIZE_ARG)).c_str());
     } else {
       exec_state_ = LDBCommandExecuteResult::FAILED(
           "Unknown argument." + arg);
@@ -223,26 +244,21 @@ void ReduceDBLevels::Help(std::string& msg) {
     LDBCommand::Help(msg);
     msg.append("[--new_levels=New number of levels] ");
     msg.append("[--print_old_levels] ");
+    msg.append("[--compression=none|snappy|zlib|bzip2] ");
+    msg.append("[--file_size= per-file size] ");
 }
 
 leveldb::Options ReduceDBLevels::PrepareOptionsForOpenDB() {
   leveldb::Options opt = LDBCommand::PrepareOptionsForOpenDB();
-  // Set to a big value to make sure we can open the db
-  opt.num_levels = 1 << 16;
+  opt.num_levels = old_levels_;
+  // Disable size compaction
+  opt.max_bytes_for_level_base = 1 << 60;
+  opt.max_bytes_for_level_multiplier = 1;
+  opt.max_mem_compaction_level = 0;
   return opt;
 }
 
-void ReduceDBLevels::DoCommand() {
-  if (new_levels_ <= 1) {
-    exec_state_ = LDBCommandExecuteResult::FAILED(
-        "Invalid number of levels.\n");
-    return;
-  }
-
-  leveldb::Status st;
-
-  leveldb::Options opt = PrepareOptionsForOpenDB();
-  if (print_old_levels_) {
+Status ReduceDBLevels::GetOldNumOfLevels(leveldb::Options& opt, int* levels) {
   TableCache* tc = new TableCache(db_path_, &opt, 10);
   const InternalKeyComparator* cmp = new InternalKeyComparator(
       opt.comparator);
@@ -251,23 +267,51 @@ void ReduceDBLevels::DoCommand() {
   // We rely the VersionSet::Recover to tell us the internal data structures
   // in the db. And the Recover() should never do any change
   // (like LogAndApply) to the manifest file.
-    st = versions->Recover();
+  Status st = versions->Recover();
+  if (!st.ok()) {
+    return st;
+  }
   int max = -1;
-    for(int i = 0; i<versions->NumberLevels(); i++) {
+  for (int i = 0; i < versions->NumberLevels(); i++) {
     if (versions->NumLevelFiles(i)) {
       max = i;
     }
   }
-    fprintf(stdout, "The old number of levels in use is %d\n", max + 1);
+
+  *levels = max + 1;
   delete versions;
+  return st;
+}
+
+void ReduceDBLevels::DoCommand() {
+  if (new_levels_ <= 1) {
+    exec_state_ = LDBCommandExecuteResult::FAILED(
+        "Invalid number of levels.\n");
+    return;
+  }
 
+  leveldb::Status st;
+  leveldb::Options opt = PrepareOptionsForOpenDB();
+  int old_level_num = -1;
+  st = GetOldNumOfLevels(opt, &old_level_num);
   if (!st.ok()) {
     exec_state_ = LDBCommandExecuteResult::FAILED(st.ToString());
     return;
   }
+
+  if (print_old_levels_) {
+    fprintf(stdout, "The old number of levels in use is %d\n", old_level_num);
+  }
+
+  if (old_level_num <= new_levels_) {
+    return;
   }
 
+  old_levels_ = old_level_num;
+
+  OpenDB();
   // Compact the whole DB to put all files to the highest level.
+  fprintf(stdout, "Compacting the db...\n");
   db_->CompactRange(NULL, NULL);
   CloseDB();
 

util/ldb_cmd.h

@@ -103,6 +103,10 @@ public:
     return opt;
   }
 
+  virtual bool NoDBOpen() {
+    return false;
+  }
+
   virtual ~LDBCommand() {
     if (db_ != NULL) {
       delete db_;
@@ -121,15 +125,19 @@ public:
       return;
     }
 
-   if (db_ == NULL) {
+   if (db_ == NULL && !NoDBOpen()) {
       OpenDB();
     }
+
     DoCommand();
     if (exec_state_.IsNotStarted()) {
       exec_state_ = LDBCommandExecuteResult::SUCCEED("");
     }
+
+    if (db_ != NULL) {
       CloseDB ();
     }
+  }
 
   virtual void DoCommand() = 0;
 
@@ -230,17 +238,28 @@ public:
   virtual leveldb::Options PrepareOptionsForOpenDB();
 
   virtual void DoCommand();
-  static void Help(std::string& msg);
 
+  virtual bool NoDBOpen() {
+    return true;
+  }
+
+  static void Help(std::string& msg);
   static std::vector<std::string> PrepareArgs(int new_levels,
       bool print_old_level = false);
 
 private:
+  int old_levels_;
   int new_levels_;
   bool print_old_levels_;
+  int file_size_;
+  enum leveldb::CompressionType compression_;
 
   static const char* NEW_LEVLES_ARG;
   static const char* PRINT_OLD_LEVELS_ARG;
+  static const char* COMPRESSION_TYPE_ARG;
+  static const char* FILE_SIZE_ARG;
+
+  Status GetOldNumOfLevels(leveldb::Options& opt, int* levels);
 };
 
 }

util/options.cc

@@ -104,7 +104,7 @@ Options::Dump(
         target_file_size_base);
     Log(log,"            Options.target_file_size_multiplier: %d",
         target_file_size_multiplier);
-    Log(log,"               Options.max_bytes_for_level_base: %d",
+    Log(log,"               Options.max_bytes_for_level_base: %ld",
         max_bytes_for_level_base);
     Log(log,"         Options.max_bytes_for_level_multiplier: %d",
         max_bytes_for_level_multiplier);