Optimize storage parameters for spatialDB

Summary: We need to start compression at level 1, while OptimizeForLevelComapaction() only sets up rocksdb to start compressing at level 2. I also adjusted some other things.

Test Plan: compiles

Reviewers: yinwang

Reviewed By: yinwang

Differential Revision: https://reviews.facebook.net/D22203

utilities/spatialdb/spatial_db.cc

@@ -552,8 +552,18 @@ class SpatialDBImpl : public SpatialDB {
 namespace {
 Options GetRocksDBOptionsFromOptions(const SpatialDBOptions& options) {
   Options rocksdb_options;
-  rocksdb_options.OptimizeLevelStyleCompaction();
   rocksdb_options.IncreaseParallelism(options.num_threads);
+  rocksdb_options.write_buffer_size = 256 * 1024 * 1024;          // 256MB
+  rocksdb_options.max_bytes_for_level_base = 1024 * 1024 * 1024;  // 1 GB
+  // only compress levels >= 1
+  rocksdb_options.compression_per_level.resize(rocksdb_options.num_levels);
+  for (int i = 0; i < rocksdb_options.num_levels; ++i) {
+    if (i == 0) {
+      rocksdb_options.compression_per_level[i] = kNoCompression;
+    } else {
+      rocksdb_options.compression_per_level[i] = kLZ4Compression;
+    }
+  }
   rocksdb_options.block_cache = NewLRUCache(options.cache_size);
   if (options.bulk_load) {
     rocksdb_options.PrepareForBulkLoad();