Export compaction reason (#242)

* export compaction reason
Signed-off-by: zhangjinpeng1987 <zhangjinpeng@pingcap.com>

librocksdb_sys/crocksdb/c.cc

@@ -143,6 +143,7 @@ using rocksdb::ColumnFamilyMetaData;
 using rocksdb::LevelMetaData;
 using rocksdb::SstFileMetaData;
 using rocksdb::CompactionOptions;
+using rocksdb::CompactionReason;
 using rocksdb::PerfLevel;
 using rocksdb::PerfContext;
 using rocksdb::BottommostLevelCompaction;
@@ -1884,6 +1885,11 @@ uint64_t crocksdb_compactionjobinfo_total_output_bytes(
   return info->rep.stats.total_output_bytes;
 }
 
+CompactionReason crocksdb_compactionjobinfo_compaction_reason(
+    const crocksdb_compactionjobinfo_t* info) {
+  return info->rep.compaction_reason;
+}
+
 /* ExternalFileIngestionInfo */
 
 const char* crocksdb_externalfileingestioninfo_cf_name(

librocksdb_sys/src/lib.rs

@@ -164,6 +164,44 @@ pub enum CompactionPriority {
     MinOverlappingRatio = 3,
 }
 
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[repr(C)]
+pub enum CompactionReason {
+    Unknown,
+    // [Level] number of L0 files > level0_file_num_compaction_trigger
+    LevelL0FilesNum,
+    // [Level] total size of level > MaxBytesForLevel()
+    LevelMaxLevelSize,
+    // [Universal] Compacting for size amplification
+    UniversalSizeAmplification,
+    // [Universal] Compacting for size ratio
+    UniversalSizeRatio,
+    // [Universal] number of sorted runs > level0_file_num_compaction_trigger
+    UniversalSortedRunNum,
+    // [FIFO] total size > max_table_files_size
+    FIFOMaxSize,
+    // [FIFO] reduce number of files.
+    FIFOReduceNumFiles,
+    // [FIFO] files with creation time < (current_time - interval)
+    FIFOTtl,
+    // Manual compaction
+    ManualCompaction,
+    // DB::SuggestCompactRange() marked files for compaction
+    FilesMarkedForCompaction,
+    // [Level] Automatic compaction within bottommost level to cleanup duplicate
+    // versions of same user key, usually due to a released snapshot.
+    BottommostFiles,
+    // Compaction based on TTL
+    Ttl,
+    // According to the comments in flush_job.cc, RocksDB treats flush as
+    // a level 0 compaction in internal stats.
+    Flush,
+    // Compaction caused by external sst file ingestion
+    ExternalSstIngestion,
+    // total number of compaction reasons, new reasons must be added above this.
+    NumOfReasons,
+}
+
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 #[repr(C)]
 pub enum DBInfoLogLevel {
@@ -1488,6 +1526,9 @@ extern "C" {
     pub fn crocksdb_compactionjobinfo_total_output_bytes(
         info: *const DBCompactionJobInfo,
     ) -> uint64_t;
+    pub fn crocksdb_compactionjobinfo_compaction_reason(
+        info: *const DBCompactionJobInfo,
+    ) -> CompactionReason;
 
     pub fn crocksdb_externalfileingestioninfo_cf_name(
         info: *const DBIngestionInfo,

src/event_listener.rs

@@ -12,8 +12,8 @@
 // limitations under the License.
 
 use crocksdb_ffi::{
-    self, DBCompactionJobInfo, DBEventListener, DBFlushJobInfo, DBIngestionInfo, DBInstance,
-    DBWriteStallInfo, WriteStallCondition,
+    self, CompactionReason, DBCompactionJobInfo, DBEventListener, DBFlushJobInfo, DBIngestionInfo,
+    DBInstance, DBWriteStallInfo, WriteStallCondition,
 };
 use libc::c_void;
 use std::path::Path;
@@ -116,6 +116,10 @@ impl CompactionJobInfo {
     pub fn total_output_bytes(&self) -> u64 {
         unsafe { crocksdb_ffi::crocksdb_compactionjobinfo_total_output_bytes(&self.0) }
     }
+
+    pub fn compaction_reason(&self) -> CompactionReason {
+        unsafe { crocksdb_ffi::crocksdb_compactionjobinfo_compaction_reason(&self.0) }
+    }
 }
 
 pub struct IngestionInfo(DBIngestionInfo);

src/lib.rs

@@ -25,9 +25,9 @@ pub use event_listener::{
     CompactionJobInfo, EventListener, FlushJobInfo, IngestionInfo, WriteStallInfo,
 };
 pub use librocksdb_sys::{
-    self as crocksdb_ffi, new_bloom_filter, CompactionPriority, DBBottommostLevelCompaction,
-    DBCompactionStyle, DBCompressionType, DBEntryType, DBInfoLogLevel, DBRecoveryMode,
-    DBStatisticsHistogramType, DBStatisticsTickerType, WriteStallCondition,
+    self as crocksdb_ffi, new_bloom_filter, CompactionPriority, CompactionReason,
+    DBBottommostLevelCompaction, DBCompactionStyle, DBCompressionType, DBEntryType, DBInfoLogLevel,
+    DBRecoveryMode, DBStatisticsHistogramType, DBStatisticsTickerType, WriteStallCondition,
 };
 pub use merge_operator::MergeOperands;
 pub use metadata::{ColumnFamilyMetaData, LevelMetaData, SstFileMetaData};

tests/test_event_listener.rs

@@ -27,6 +27,7 @@ struct EventCounter {
     output_records: Arc<AtomicUsize>,
     input_bytes: Arc<AtomicUsize>,
     output_bytes: Arc<AtomicUsize>,
+    manual_compaction: Arc<AtomicUsize>,
 }
 
 impl Drop for EventCounter {
@@ -75,6 +76,10 @@ impl EventListener for EventCounter {
             .fetch_add(info.total_input_bytes() as usize, Ordering::SeqCst);
         self.output_bytes
             .fetch_add(info.total_output_bytes() as usize, Ordering::SeqCst);
+
+        if info.compaction_reason() == CompactionReason::ManualCompaction {
+            self.manual_compaction.fetch_add(1, Ordering::SeqCst);
+        }
     }
 
     fn on_external_file_ingested(&self, info: &IngestionInfo) {
@@ -199,6 +204,7 @@ fn test_event_listener_basic() {
     assert!(
         counter.input_bytes.load(Ordering::SeqCst) > counter.output_bytes.load(Ordering::SeqCst)
     );
+    assert_eq!(counter.manual_compaction.load(Ordering::SeqCst), 1);
 }
 
 #[test]