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
This commit is contained in:
Siying Dong 2017-03-29 11:42:56 -07:00 committed by sdong
parent b900f6e197
commit bae811fca0
6 changed files with 128 additions and 75 deletions

View File

@ -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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25 / 1.25 / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
}
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25 / 1.25, GetDbDelayedWriteRate());
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,
dbfull()->TEST_write_controler().delayed_write_rate());
ASSERT_EQ(kBaseRate / 1.25, GetDbDelayedWriteRate());
}
TEST_F(ColumnFamilyTest, CompactionSpeedupTwoColumnFamilies) {

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@ -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.

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@ -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

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@ -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

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

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@ -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) {