Expose the stalling information through DB::GetProperty()

Summary:
Add two DB properties: rocksdb.actual_delayed_write_rate and rocksdb.is_write_stooped, for people to know whether current writes are being throttled.
Closes https://github.com/facebook/rocksdb/pull/2043

Differential Revision: D4782975

Pulled By: siying

fbshipit-source-id: 6b2f5cf

db/column_family_test.cc

@@ -213,6 +213,30 @@ class ColumnFamilyTest : public testing::Test {
 #endif
   }
 
+  bool IsDbWriteStopped() {
+#ifndef ROCKSDB_LITE
+    uint64_t v;
+    EXPECT_TRUE(dbfull()->GetIntProperty("rocksdb.is-write-stopped", &v));
+    return (v == 1);
+#else
+    return dbfull()->TEST_write_controler().IsStopped();
+#endif  // !ROCKSDB_LITE
+  }
+
+  uint64_t GetDbDelayedWriteRate() {
+#ifndef ROCKSDB_LITE
+    uint64_t v;
+    EXPECT_TRUE(
+        dbfull()->GetIntProperty("rocksdb.actual-delayed-write-rate", &v));
+    return v;
+#else
+    if (!dbfull()->TEST_write_controler().NeedsDelay()) {
+      return 0;
+    }
+    return dbfull()->TEST_write_controler().delayed_write_rate();
+#endif  // !ROCKSDB_LITE
+  }
+
   void Destroy() {
     Close();
     ASSERT_OK(DestroyDB(dbname_, Options(db_options_, column_family_options_)));
@@ -2453,173 +2477,165 @@ TEST_F(ColumnFamilyTest, WriteStallSingleColumnFamily) {
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(50);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(201);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
   ASSERT_EQ(6, dbfull()->TEST_BGCompactionsAllowed());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(400);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
   ASSERT_EQ(6, dbfull()->TEST_BGCompactionsAllowed());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(500);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25 / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(450);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(205);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(202);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(201);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(198);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(399);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(599);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(2001);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
   ASSERT_EQ(6, dbfull()->TEST_BGCompactionsAllowed());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(3001);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(390);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(100);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage->set_l0_delay_trigger_count(100);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
   ASSERT_EQ(6, dbfull()->TEST_BGCompactionsAllowed());
 
   vstorage->set_l0_delay_trigger_count(101);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->set_l0_delay_trigger_count(0);
   vstorage->TEST_set_estimated_compaction_needed_bytes(300);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25 / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->set_l0_delay_trigger_count(101);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25 / 1.25 / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25 / 1.25 / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(200);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25 / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->set_l0_delay_trigger_count(0);
   vstorage->TEST_set_estimated_compaction_needed_bytes(0);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   mutable_cf_options.disable_auto_compactions = true;
   dbfull()->TEST_write_controler().set_delayed_write_rate(kBaseRate);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage->set_l0_delay_trigger_count(50);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
+  ASSERT_EQ(0, GetDbDelayedWriteRate());
   ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->set_l0_delay_trigger_count(60);
   vstorage->TEST_set_estimated_compaction_needed_bytes(300);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
+  ASSERT_EQ(0, GetDbDelayedWriteRate());
   ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
 
   mutable_cf_options.disable_auto_compactions = false;
   vstorage->set_l0_delay_trigger_count(70);
   vstorage->TEST_set_estimated_compaction_needed_bytes(500);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage->set_l0_delay_trigger_count(71);
   vstorage->TEST_set_estimated_compaction_needed_bytes(501);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 }
 
 TEST_F(ColumnFamilyTest, CompactionSpeedupSingleColumnFamily) {
@@ -2711,60 +2727,55 @@ TEST_F(ColumnFamilyTest, WriteStallTwoColumnFamilies) {
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(50);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage1->TEST_set_estimated_compaction_needed_bytes(201);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(!dbfull()->TEST_write_controler().NeedsDelay());
 
   vstorage1->TEST_set_estimated_compaction_needed_bytes(600);
   cfd1->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(70);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate, dbfull()->TEST_write_controler().delayed_write_rate());
+  ASSERT_EQ(kBaseRate, GetDbDelayedWriteRate());
 
   vstorage1->TEST_set_estimated_compaction_needed_bytes(800);
   cfd1->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(300);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25 / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage1->TEST_set_estimated_compaction_needed_bytes(700);
   cfd1->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage->TEST_set_estimated_compaction_needed_bytes(500);
   cfd->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25 / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 
   vstorage1->TEST_set_estimated_compaction_needed_bytes(600);
   cfd1->RecalculateWriteStallConditions(mutable_cf_options);
-  ASSERT_TRUE(!dbfull()->TEST_write_controler().IsStopped());
+  ASSERT_TRUE(!IsDbWriteStopped());
   ASSERT_TRUE(dbfull()->TEST_write_controler().NeedsDelay());
-  ASSERT_EQ(kBaseRate / 1.25,
+  ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
-            dbfull()->TEST_write_controler().delayed_write_rate());
 }
 
 TEST_F(ColumnFamilyTest, CompactionSpeedupTwoColumnFamilies) {

db/db_impl.h

@@ -465,6 +465,8 @@ class DBImpl : public DB {
     return num_running_compactions_;
   }
 
+  const WriteController& write_controller() { return write_controller_; }
+
   // hollow transactions shell used for recovery.
   // these will then be passed to TransactionDB so that
   // locks can be reacquired before writing can resume.

db/internal_stats.cc

@@ -232,6 +232,9 @@ static const std::string aggregated_table_properties_at_level =
     aggregated_table_properties + "-at-level";
 static const std::string num_running_compactions = "num-running-compactions";
 static const std::string num_running_flushes = "num-running-flushes";
+static const std::string actual_delayed_write_rate =
+    "actual-delayed-write-rate";
+static const std::string is_write_stopped = "is-write-stopped";
 
 const std::string DB::Properties::kNumFilesAtLevelPrefix =
                       rocksdb_prefix + num_files_at_level_prefix;
@@ -297,6 +300,10 @@ const std::string DB::Properties::kAggregatedTableProperties =
     rocksdb_prefix + aggregated_table_properties;
 const std::string DB::Properties::kAggregatedTablePropertiesAtLevel =
     rocksdb_prefix + aggregated_table_properties_at_level;
+const std::string DB::Properties::kActualDelayedWriteRate =
+    rocksdb_prefix + actual_delayed_write_rate;
+const std::string DB::Properties::kIsWriteStopped =
+    rocksdb_prefix + is_write_stopped;
 
 const std::unordered_map<std::string, DBPropertyInfo>
     InternalStats::ppt_name_to_info = {
@@ -385,6 +392,11 @@ const std::unordered_map<std::string, DBPropertyInfo>
         {DB::Properties::kNumRunningCompactions,
          {false, nullptr, &InternalStats::HandleNumRunningCompactions,
           nullptr}},
+        {DB::Properties::kActualDelayedWriteRate,
+         {false, nullptr, &InternalStats::HandleActualDelayedWriteRate,
+          nullptr}},
+        {DB::Properties::kIsWriteStopped,
+         {false, nullptr, &InternalStats::HandleIsWriteStopped, nullptr}},
 };
 
 const DBPropertyInfo* GetPropertyInfo(const Slice& property) {
@@ -716,6 +728,23 @@ bool InternalStats::HandleMinLogNumberToKeep(uint64_t* value, DBImpl* db,
   return true;
 }
 
+bool InternalStats::HandleActualDelayedWriteRate(uint64_t* value, DBImpl* db,
+                                                 Version* version) {
+  const WriteController& wc = db->write_controller();
+  if (!wc.NeedsDelay()) {
+    *value = 0;
+  } else {
+    *value = wc.delayed_write_rate();
+  }
+  return true;
+}
+
+bool InternalStats::HandleIsWriteStopped(uint64_t* value, DBImpl* db,
+                                         Version* version) {
+  *value = db->write_controller().IsStopped() ? 1 : 0;
+  return true;
+}
+
 void InternalStats::DumpDBStats(std::string* value) {
   char buf[1000];
   // DB-level stats, only available from default column family

db/internal_stats.h

@@ -402,6 +402,9 @@ class InternalStats {
   bool HandleEstimateLiveDataSize(uint64_t* value, DBImpl* db,
                                   Version* version);
   bool HandleMinLogNumberToKeep(uint64_t* value, DBImpl* db, Version* version);
+  bool HandleActualDelayedWriteRate(uint64_t* value, DBImpl* db,
+                                    Version* version);
+  bool HandleIsWriteStopped(uint64_t* value, DBImpl* db, Version* version);
 
   // Total number of background errors encountered. Every time a flush task
   // or compaction task fails, this counter is incremented. The failure can

db/write_controller.h

@@ -80,7 +80,6 @@ class WriteController {
  private:
   uint64_t NowMicrosMonotonic(Env* env);
 
- private:
   friend class WriteControllerToken;
   friend class StopWriteToken;
   friend class DelayWriteToken;

include/rocksdb/db.h

@@ -527,6 +527,13 @@ class DB {
     //      one but only returns the aggregated table properties of the
     //      specified level "N" at the target column family.
     static const std::string kAggregatedTablePropertiesAtLevel;
+
+    //  "rocksdb.actual-delayed-write-rate" - returns the current actual delayed
+    //      write rate. 0 means no delay.
+    static const std::string kActualDelayedWriteRate;
+
+    //  "rocksdb.is-write-stopped" - Return 1 if write has been stopped.
+    static const std::string kIsWriteStopped;
   };
 #endif /* ROCKSDB_LITE */
 
@@ -575,6 +582,8 @@ class DB {
   //  "rocksdb.estimate-pending-compaction-bytes"
   //  "rocksdb.num-running-compactions"
   //  "rocksdb.num-running-flushes"
+  //  "rocksdb.actual-delayed-write-rate"
+  //  "rocksdb.is-write-stopped"
   virtual bool GetIntProperty(ColumnFamilyHandle* column_family,
                               const Slice& property, uint64_t* value) = 0;
   virtual bool GetIntProperty(const Slice& property, uint64_t* value) {