Add `read_amp_bytes_per_bit` option (#136)

librocksdb_sys/crocksdb/c.cc

@@ -1563,6 +1563,11 @@ void crocksdb_block_based_options_set_pin_l0_filter_and_index_blocks_in_cache(
   options->rep.pin_l0_filter_and_index_blocks_in_cache = v;
 }
 
+void crocksdb_block_based_options_set_read_amp_bytes_per_bit(
+    crocksdb_block_based_table_options_t* options, int v) {
+  options->rep.read_amp_bytes_per_bit = v;
+}
+
 void crocksdb_options_set_block_based_table_factory(
     crocksdb_options_t *opt,
     crocksdb_block_based_table_options_t* table_options) {

librocksdb_sys/crocksdb/crocksdb/c.h

@@ -594,6 +594,9 @@ crocksdb_block_based_options_set_cache_index_and_filter_blocks(
 extern C_ROCKSDB_LIBRARY_API void
 crocksdb_block_based_options_set_pin_l0_filter_and_index_blocks_in_cache(
     crocksdb_block_based_table_options_t*, unsigned char);
+extern C_ROCKSDB_LIBRARY_API void
+crocksdb_block_based_options_set_read_amp_bytes_per_bit(
+    crocksdb_block_based_table_options_t*, int);
 extern C_ROCKSDB_LIBRARY_API void crocksdb_options_set_block_based_table_factory(
     crocksdb_options_t* opt, crocksdb_block_based_table_options_t* table_options);
 

librocksdb_sys/src/lib.rs

@@ -351,6 +351,10 @@ extern "C" {
         block_options: *mut DBBlockBasedTableOptions,
         v: c_uchar,
     );
+    pub fn crocksdb_block_based_options_set_read_amp_bytes_per_bit(
+        block_options: *mut DBBlockBasedTableOptions,
+        v: c_int,
+    );
     pub fn crocksdb_options_increase_parallelism(options: *mut Options, threads: c_int);
     pub fn crocksdb_options_optimize_level_style_compaction(
         options: *mut Options,

src/rocksdb_options.rs

@@ -119,6 +119,15 @@ impl BlockBasedOptions {
                 v as u8);
         }
     }
+
+    pub fn set_read_amp_bytes_per_bit(&mut self, v: u32) {
+        unsafe {
+            crocksdb_ffi::crocksdb_block_based_options_set_read_amp_bytes_per_bit(
+                self.inner,
+                v as c_int,
+            )
+        }
+    }
 }
 
 pub struct RateLimiter {

tests/test_rocksdb_options.rs

@@ -562,3 +562,31 @@ fn test_read_options() {
     }
     assert!(key_count == 3);
 }
+
+#[test]
+fn test_block_based_options() {
+    let path = TempDir::new("_rust_rocksdb_block_based_options").expect("");
+    let path_str = path.path().to_str().unwrap();
+
+    let mut opts = DBOptions::new();
+    opts.create_if_missing(true);
+    opts.enable_statistics();
+    opts.set_stats_dump_period_sec(60);
+    let mut bopts = BlockBasedOptions::new();
+    bopts.set_read_amp_bytes_per_bit(16);
+    let mut cfopts = ColumnFamilyOptions::new();
+    cfopts.set_block_based_table_factory(&bopts);
+
+    let db = DB::open_cf(opts.clone(), path_str, vec!["default"], vec![cfopts]).unwrap();
+    db.put(b"a", b"a").unwrap();
+    db.flush(true).unwrap();
+    db.get(b"a").unwrap();
+    assert_ne!(
+        opts.get_statistics_ticker_count(TickerType::ReadAmpTotalReadBytes),
+        0
+    );
+    assert_ne!(
+        opts.get_statistics_ticker_count(TickerType::ReadAmpEstimateUsefulBytes),
+        0
+    );
+}