Add histogram max (#133)

librocksdb_sys/crocksdb/c.cc

@@ -2386,7 +2386,8 @@ unsigned char crocksdb_options_statistics_get_histogram(
     double* percentile95,
     double* percentile99,
     double* average,
-    double* standard_deviation) {
+    double* standard_deviation,
+    double* max) {
   rocksdb::Statistics* statistics = opt->rep.statistics.get();
   if (statistics) {
     crocksdb_histogramdata_t data;
@@ -2396,6 +2397,7 @@ unsigned char crocksdb_options_statistics_get_histogram(
     *percentile99 = data.rep.percentile99;
     *average = data.rep.average;
     *standard_deviation = data.rep.standard_deviation;
+    *max = data.rep.max;
     return 1;
   }
   return 0;

librocksdb_sys/crocksdb/crocksdb/c.h

@@ -801,7 +801,8 @@ extern C_ROCKSDB_LIBRARY_API unsigned char crocksdb_options_statistics_get_histo
     double* percentile95,
     double* percentile99,
     double* average,
-    double* standard_deviation);
+    double* standard_deviation,
+    double* max);
 
 extern C_ROCKSDB_LIBRARY_API void crocksdb_options_set_max_write_buffer_number(
     crocksdb_options_t*, int);

librocksdb_sys/src/lib.rs

@@ -438,6 +438,7 @@ extern "C" {
         percentile99: *mut c_double,
         average: *mut c_double,
         standard_deviation: *mut c_double,
+        max: *mut c_double,
     ) -> bool;
     pub fn crocksdb_options_set_stats_dump_period_sec(options: *mut Options, v: usize);
     pub fn crocksdb_options_set_num_levels(options: *mut Options, v: c_int);

src/rocksdb_options.rs

@@ -38,6 +38,7 @@ pub struct HistogramData {
     pub percentile99: f64,
     pub average: f64,
     pub standard_deviation: f64,
+    pub max: f64,
 }
 
 pub struct BlockBasedOptions {
@@ -570,6 +571,7 @@ impl DBOptions {
                 &mut data.percentile99,
                 &mut data.average,
                 &mut data.standard_deviation,
+                &mut data.max,
             );
             if !ret {
                 return None;

tests/test_rocksdb_options.rs

@@ -73,6 +73,10 @@ fn test_enable_statistics() {
     opts.enable_statistics();
     opts.set_stats_dump_period_sec(60);
     assert!(opts.get_statistics().is_some());
+    assert!(
+        opts.get_statistics_histogram(HistogramType::SeekMicros)
+            .is_some()
+    );
     assert!(
         opts.get_statistics_histogram_string(HistogramType::SeekMicros)
             .is_some()