Fix and test when disable statistics (#172)

librocksdb_sys/crocksdb/c.cc

@@ -1607,7 +1607,10 @@ size_t crocksdb_options_get_block_cache_usage(crocksdb_options_t *opt) {
   if (opt && opt->rep.table_factory != nullptr) {
     void* table_opt = opt->rep.table_factory->GetOptions();
     if (table_opt && strcmp(opt->rep.table_factory->Name(), block_base_table_str) == 0) {
-      return static_cast<BlockBasedTableOptions*>(table_opt)->block_cache->GetUsage();
+      auto opts = static_cast<BlockBasedTableOptions*>(table_opt);
+      if (opts->block_cache) {
+        return opts->block_cache->GetUsage();
+      }
     }
   }
   return 0;
@@ -1966,7 +1969,10 @@ void crocksdb_options_enable_statistics(crocksdb_options_t* opt, unsigned char v
 }
 
 void crocksdb_options_reset_statistics(crocksdb_options_t* opt) {
-  opt->rep.statistics->Reset();
+  auto statistics = opt->rep.statistics.get();
+  if (statistics) {
+    statistics->Reset();
+  }
 }
 
 void crocksdb_options_set_num_levels(crocksdb_options_t* opt, int n) {

tests/test_rocksdb_options.rs

@@ -369,6 +369,16 @@ fn test_get_block_cache_usage() {
     assert!(db.get_options().get_block_cache_usage() > 0);
 }
 
+#[test]
+fn test_disable_block_cache() {
+    let mut cf_opts = ColumnFamilyOptions::new();
+    assert_eq!(cf_opts.get_block_cache_usage(), 0);
+    let mut block_opts = BlockBasedOptions::new();
+    block_opts.set_no_block_cache(true);
+    cf_opts.set_block_based_table_factory(&block_opts);
+    assert_eq!(cf_opts.get_block_cache_usage(), 0);
+}
+
 #[test]
 fn test_set_level_compaction_dynamic_level_bytes() {
     let path = TempDir::new("_rust_rocksdb_level_compaction_dynamic_level_bytes").expect("");

tests/test_statistics.rs

@@ -52,3 +52,35 @@ fn test_db_statistics() {
         .unwrap();
     assert_eq!(get_micros.max, 0.0);
 }
+
+#[test]
+fn test_disable_db_statistics() {
+    let path = TempDir::new("_rust_rocksdb_statistics").expect("");
+    let mut opts = DBOptions::new();
+    opts.create_if_missing(true);
+    opts.enable_statistics(false);
+    let db = DB::open(opts, path.path().to_str().unwrap()).unwrap();
+    let wopts = WriteOptions::new();
+
+    db.put_opt(b"k0", b"a", &wopts).unwrap();
+    db.put_opt(b"k1", b"b", &wopts).unwrap();
+    db.put_opt(b"k2", b"c", &wopts).unwrap();
+    db.flush(true /* sync */).unwrap(); // flush memtable to sst file.
+    assert_eq!(db.get(b"k0").unwrap().unwrap(), b"a");
+    assert_eq!(db.get(b"k1").unwrap().unwrap(), b"b");
+    assert_eq!(db.get(b"k2").unwrap().unwrap(), b"c");
+
+    assert_eq!(db.get_statistics_ticker_count(TickerType::BlockCacheHit), 0);
+    assert_eq!(
+        db.get_and_reset_statistics_ticker_count(TickerType::BlockCacheHit),
+        0
+    );
+    assert!(
+        db.get_statistics_histogram_string(HistogramType::GetMicros)
+            .is_none()
+    );
+    assert!(
+        db.get_statistics_histogram(HistogramType::GetMicros)
+            .is_none()
+    );
+}