fix: set burst_size of _write_token_bucket in fds_service to double m…

…ax (#755)

src/block_service/fds/fds_service.cpp

@@ -119,22 +119,15 @@ const std::string fds_service::FILE_MD5_KEY = "content-md5";
 
 fds_service::fds_service()
 {
-    /// In normal scenario, the sst file size of level 0 is write_buffer_size * [0.75, 1.25]
-    /// And in BULK_LOAD scenario, it is 4 * write_buffer_size * [0.75, 1.25].
-    /// In rdsn, we can't get the scenario, so if we take BULK_LOAD scenario into consideration,
-    /// we must set max_sst_file_size to 4 * write_buffer_size * [0.75, 1.25], which is too big.
-    /// So in this implementation, we don't take BULK_LOAD scenario into consideration.
-    uint64_t max_sst_file_size = std::max(FLAGS_rocksdb_target_file_size_base,
-                                          (uint64_t)1.25 * FLAGS_rocksdb_write_buffer_size);
-
     /// For write operation, we can't send a file in batches. Because putContent interface of fds
     /// will overwrite what was sent before for the same file. So we must send a file as a whole.
     /// If file size > burst size, the file will be rejected by the token bucket.
-    ///  Here we set burst_size = max_sst_file_size + 3MB, a litte greater than max_sst_file_size
-    uint32_t burst_size =
-        std::max(2.0 * (FLAGS_fds_write_limit_rate << 20), max_sst_file_size + 3e6);
-    _write_token_bucket.reset(new folly::TokenBucket(FLAGS_fds_write_limit_rate << 20, burst_size));
-    burst_size = 2 * FLAGS_fds_read_limit_rate << 20;
+    ///  Here we set burst_size to max value of double, in order to make file not rejected by the
+    ///  token bucket
+    _write_token_bucket.reset(new folly::TokenBucket(FLAGS_fds_write_limit_rate << 20,
+                                                     std::numeric_limits<double>::max()));
+
+    uint32_t burst_size = 2 * FLAGS_fds_read_limit_rate << 20;
     _read_token_bucket.reset(new folly::TokenBucket(FLAGS_fds_read_limit_rate << 20, burst_size));
 }
 
@@ -444,7 +437,6 @@ error_code fds_file_object::get_content_in_batches(uint64_t start,
                                                    /*out*/ std::ostream &os,
                                                    /*out*/ uint64_t &transfered_bytes)
 {
-    // the max batch size is 1MB
     const uint64_t BATCH_SIZE = std::min(FLAGS_fds_read_limit_rate, FLAGS_fds_read_batch_size)
                                 << 20;
     error_code err = ERR_OK;