Add DB::GetIntProperty() to return integer properties to be returned as integers

Summary: We have quite some properties that are integers and we are adding more. Add a function to directly return them as an integer, instead of a string

Test Plan: Add several unit test checks

Reviewers: yhchiang, igor, dhruba, haobo, ljin

Reviewed By: ljin

Subscribers: yoshinorim, leveldb

Differential Revision: https://reviews.facebook.net/D20637

HISTORY.md

@@ -11,6 +11,7 @@
 * Moved include/utilities/*.h to include/rocksdb/utilities/*.h
 * Statistics APIs now take uint32_t as type instead of Tickers. Also make two access functions getTickerCount and histogramData const
 * Add DB property rocksdb.estimate-num-keys, estimated number of live keys in DB.
+* Add DB::GetIntProperty(), which returns DB properties that are integer as uint64_t.
 
 ## 3.3.0 (7/10/2014)
 ### New Features

db/db_impl.cc

@@ -4372,6 +4372,15 @@ bool DBImpl::GetProperty(ColumnFamilyHandle* column_family,
   return cfd->internal_stats()->GetProperty(property_type, property, value);
 }
 
+bool DBImpl::GetIntProperty(ColumnFamilyHandle* column_family,
+                            const Slice& property, uint64_t* value) {
+  auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
+  auto cfd = cfh->cfd();
+  DBPropertyType property_type = GetPropertyType(property);
+  MutexLock l(&mutex_);
+  return cfd->internal_stats()->GetIntProperty(property_type, property, value);
+}
+
 void DBImpl::GetApproximateSizes(ColumnFamilyHandle* column_family,
                                  const Range* range, int n, uint64_t* sizes) {
   // TODO(opt): better implementation

db/db_impl.h

@@ -96,6 +96,9 @@ class DBImpl : public DB {
   using DB::GetProperty;
   virtual bool GetProperty(ColumnFamilyHandle* column_family,
                            const Slice& property, std::string* value);
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override;
   using DB::GetApproximateSizes;
   virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
                                    const Range* range, int n, uint64_t* sizes);

db/db_test.cc

@@ -2486,6 +2486,7 @@ TEST(DBTest, GetProperty) {
 
   std::string big_value(1000000 * 2, 'x');
   std::string num;
+  uint64_t int_num;
   SetPerfLevel(kEnableTime);
 
   ASSERT_OK(dbfull()->Put(writeOpt, "k1", big_value));
@@ -2512,6 +2513,17 @@ TEST(DBTest, GetProperty) {
   ASSERT_EQ(num, "0");
   ASSERT_TRUE(dbfull()->GetProperty("rocksdb.estimate-num-keys", &num));
   ASSERT_EQ(num, "4");
+  // Verify the same set of properties through GetIntProperty
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.num-immutable-mem-table", &int_num));
+  ASSERT_EQ(int_num, 2U);
+  ASSERT_TRUE(
+      dbfull()->GetIntProperty("rocksdb.mem-table-flush-pending", &int_num));
+  ASSERT_EQ(int_num, 1U);
+  ASSERT_TRUE(dbfull()->GetIntProperty("rocksdb.compaction-pending", &int_num));
+  ASSERT_EQ(int_num, 0);
+  ASSERT_TRUE(dbfull()->GetIntProperty("rocksdb.estimate-num-keys", &int_num));
+  ASSERT_EQ(int_num, 4);
 
   sleeping_task_high.WakeUp();
   sleeping_task_high.WaitUntilDone();
@@ -6604,6 +6616,11 @@ class ModelDB: public DB {
                            const Slice& property, std::string* value) {
     return false;
   }
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override {
+    return false;
+  }
   using DB::GetApproximateSizes;
   virtual void GetApproximateSizes(ColumnFamilyHandle* column_family,
                                    const Range* range, int n, uint64_t* sizes) {

db/internal_stats.cc

@@ -126,6 +126,15 @@ DBPropertyType GetPropertyType(const Slice& property) {
 
 bool InternalStats::GetProperty(DBPropertyType property_type,
                                 const Slice& property, std::string* value) {
+  if (property_type > kStartIntTypes) {
+    uint64_t int_value;
+    bool ret_value = GetIntProperty(property_type, property, &int_value);
+    if (ret_value) {
+      *value = std::to_string(int_value);
+    }
+    return ret_value;
+  }
+
   Version* current = cfd_->current();
   Slice in = property;
 
@@ -179,40 +188,51 @@ bool InternalStats::GetProperty(DBPropertyType property_type,
     case kSsTables:
       *value = current->DebugString();
       return true;
+    default:
+      return false;
+  }
+}
+
+bool InternalStats::GetIntProperty(DBPropertyType property_type,
+                                   const Slice& property,
+                                   uint64_t* value) const {
+  Version* current = cfd_->current();
+
+  switch (property_type) {
     case kNumImmutableMemTable:
-      *value = std::to_string(cfd_->imm()->size());
+      *value = cfd_->imm()->size();
       return true;
     case kMemtableFlushPending:
       // Return number of mem tables that are ready to flush (made immutable)
-      *value = std::to_string(cfd_->imm()->IsFlushPending() ? 1 : 0);
+      *value = (cfd_->imm()->IsFlushPending() ? 1 : 0);
       return true;
     case kCompactionPending:
       // 1 if the system already determines at least one compacdtion is needed.
       // 0 otherwise,
-      *value = std::to_string(current->NeedsCompaction() ? 1 : 0);
+      *value = (current->NeedsCompaction() ? 1 : 0);
       return true;
     case kBackgroundErrors:
       // Accumulated number of  errors in background flushes or compactions.
-      *value = std::to_string(GetBackgroundErrorCount());
+      *value = GetBackgroundErrorCount();
       return true;
     case kCurSizeActiveMemTable:
       // Current size of the active memtable
-      *value = std::to_string(cfd_->mem()->ApproximateMemoryUsage());
+      *value = cfd_->mem()->ApproximateMemoryUsage();
       return true;
     case kNumEntriesInMutableMemtable:
       // Current size of the active memtable
-      *value = std::to_string(cfd_->mem()->GetNumEntries());
+      *value = cfd_->mem()->GetNumEntries();
       return true;
     case kNumEntriesInImmutableMemtable:
       // Current size of the active memtable
-      *value = std::to_string(cfd_->imm()->current()->GetTotalNumEntries());
+      *value = cfd_->imm()->current()->GetTotalNumEntries();
       return true;
     case kEstimatedNumKeys:
       // Estimate number of entries in the column family:
       // Use estimated entries in tables + total entries in memtables.
-      *value = std::to_string(cfd_->mem()->GetNumEntries() +
-                              cfd_->imm()->current()->GetTotalNumEntries() +
-                              current->GetEstimatedActiveKeys());
+      *value = cfd_->mem()->GetNumEntries() +
+               cfd_->imm()->current()->GetTotalNumEntries() +
+               current->GetEstimatedActiveKeys();
       return true;
     default:
       return false;

db/internal_stats.h

@@ -21,13 +21,15 @@ namespace rocksdb {
 class MemTableList;
 class DBImpl;
 
-enum DBPropertyType {
+enum DBPropertyType : uint32_t {
+  kUnknown,
   kNumFilesAtLevel,  // Number of files at a specific level
   kLevelStats,       // Return number of files and total sizes of each level
   kCFStats,          // Return general statitistics of CF
   kDBStats,          // Return general statitistics of DB
   kStats,            // Return general statitistics of both DB and CF
   kSsTables,         // Return a human readable string of current SST files
+  kStartIntTypes,    // ---- Dummy value to indicate the start of integer values
   kNumImmutableMemTable,   // Return number of immutable mem tables
   kMemtableFlushPending,   // Return 1 if mem table flushing is pending,
                            // otherwise 0.
@@ -39,7 +41,6 @@ enum DBPropertyType {
   kNumEntriesInImmutableMemtable,  // Return sum of number of entries in all
                                    // the immutable mem tables.
   kEstimatedNumKeys,  // Estimated total number of keys in the database.
-  kUnknown,
 };
 
 extern DBPropertyType GetPropertyType(const Slice& property);
@@ -193,6 +194,9 @@ class InternalStats {
   bool GetProperty(DBPropertyType property_type, const Slice& property,
                    std::string* value);
 
+  bool GetIntProperty(DBPropertyType property_type, const Slice& property,
+                      uint64_t* value) const;
+
  private:
   void DumpDBStats(std::string* value);
   void DumpCFStats(std::string* value);

include/rocksdb/db.h

@@ -307,6 +307,14 @@ class DB {
     return GetProperty(DefaultColumnFamily(), property, value);
   }
 
+  // Similar to GetProperty(), but only works for a subset of properties whose
+  // return value is an integer. Return the value by integer.
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) = 0;
+  virtual bool GetIntProperty(const Slice& property, uint64_t* value) {
+    return GetIntProperty(DefaultColumnFamily(), property, value);
+  }
+
   // For each i in [0,n-1], store in "sizes[i]", the approximate
   // file system space used by keys in "[range[i].start .. range[i].limit)".
   //

include/rocksdb/utilities/stackable_db.h

@@ -107,7 +107,13 @@ class StackableDB : public DB {
   using DB::GetProperty;
   virtual bool GetProperty(ColumnFamilyHandle* column_family,
                            const Slice& property, std::string* value) override {
-      return db_->GetProperty(column_family, property, value);
+    return db_->GetProperty(column_family, property, value);
+  }
+
+  using DB::GetIntProperty;
+  virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
+                              const Slice& property, uint64_t* value) override {
+    return db_->GetIntProperty(column_family, property, value);
   }
 
   using DB::GetApproximateSizes;