Simplify DB::open to use the shared block cache

  Address review feedback: remove the Option<&Cache> parameter and the
  owned_cache lifetime workaround.

Author: EddieHouston

src/new_index/db.rs

@@ -90,11 +90,7 @@ pub enum DBFlush {
 }
 
 impl DB {
-    pub fn open(path: &Path, config: &Config, verify_compat: bool) -> DB {
-        Self::open_with_cache(path, config, verify_compat, None)
-    }
-
-    pub fn open_with_cache(path: &Path, config: &Config, verify_compat: bool, shared_cache: Option<&rocksdb::Cache>) -> DB {
+    pub fn open(path: &Path, config: &Config, verify_compat: bool, shared_cache: &rocksdb::Cache) -> DB {
         debug!("opening DB at {:?}", path);
         let mut db_opts = rocksdb::Options::default();
         db_opts.create_if_missing(true);
@@ -152,16 +148,7 @@ impl DB {
 
         // Configure block cache and table options
         let mut block_opts = rocksdb::BlockBasedOptions::default();
-        let owned_cache: rocksdb::Cache;
-        let cache = match shared_cache {
-            Some(c) => c,
-            None => {
-                let cache_size_bytes = config.db_block_cache_mb * 1024 * 1024;
-                owned_cache = rocksdb::Cache::new_lru_cache(cache_size_bytes);
-                &owned_cache
-            }
-        };
-        block_opts.set_block_cache(cache);
+        block_opts.set_block_cache(shared_cache);
         // When --cache-index-filter-blocks is passed, store index and filter blocks
         // inside the block cache so their memory is bounded by --db-block-cache-mb.
         // Without this (the default), RocksDB keeps them on the heap where they may

src/new_index/schema.rs

@@ -68,17 +68,17 @@ impl Store {
         // needs without being artificially capped at 1/3 of the total.
         let cache_size_bytes = config.db_block_cache_mb * 1024 * 1024;
         let shared_cache = rocksdb::Cache::new_lru_cache(cache_size_bytes);
-        info!("shared LRU block cache: db_block_cache_mb='{}'", config.db_block_cache_mb);
+        debug!("shared LRU block cache: db_block_cache_mb='{}'", config.db_block_cache_mb);
 
-        let txstore_db = DB::open_with_cache(&path.join("txstore"), config, verify_compat, Some(&shared_cache));
+        let txstore_db = DB::open(&path.join("txstore"), config, verify_compat, &shared_cache);
         let added_blockhashes = load_blockhashes(&txstore_db, &BlockRow::done_filter());
         debug!("{} blocks were added", added_blockhashes.len());
 
-        let history_db = DB::open_with_cache(&path.join("history"), config, verify_compat, Some(&shared_cache));
+        let history_db = DB::open(&path.join("history"), config, verify_compat, &shared_cache);
         let indexed_blockhashes = load_blockhashes(&history_db, &BlockRow::done_filter());
         debug!("{} blocks were indexed", indexed_blockhashes.len());
 
-        let cache_db = DB::open_with_cache(&path.join("cache"), config, verify_compat, Some(&shared_cache));
+        let cache_db = DB::open(&path.join("cache"), config, verify_compat, &shared_cache);
 
         let db_metrics = Arc::new(RocksDbMetrics::new(&metrics));
         txstore_db.start_stats_exporter(Arc::clone(&db_metrics), "txstore_db");