fix: tweak rocksdb options

Author: Ludo Galabru

components/chainhook-event-observer/src/hord/db/mod.rs

@@ -415,15 +415,26 @@ fn get_default_hord_db_file_path_rocks_db(base_dir: &PathBuf) -> PathBuf {
     destination_path
 }
 
+fn rocks_db_default_options() -> rocksdb::Options {
+    let mut opts = rocksdb::Options::default();
+    opts.create_if_missing(true);
+    // Per rocksdb documentation:
+    // If cache_index_and_filter_blocks is false (which is default), 
+    // the number of index/filter blocks is controlled by option max_open_files. 
+    // If you are certain that your ulimit will always be bigger than number of files in the database, 
+    // we recommend setting max_open_files to -1, which means infinity. 
+    // This option will preload all filter and index blocks and will not need to maintain LRU of files. 
+    // Setting max_open_files to -1 will get you the best possible performance.
+    opts.set_max_open_files(-1);
+    opts
+}
+
 pub fn open_readonly_hord_db_conn_rocks_db(
     base_dir: &PathBuf,
     _ctx: &Context,
 ) -> Result<DB, String> {
     let path = get_default_hord_db_file_path_rocks_db(&base_dir);
-    let mut opts = rocksdb::Options::default();
-    opts.create_if_missing(true);
-    opts.set_max_open_files(5000);
-    // opts.set_disable_auto_compactions(true);
+    let opts = rocks_db_default_options();
     let db = DB::open_for_read_only(&opts, path, false)
         .map_err(|e| format!("unable to open blocks_db: {}", e.to_string()))?;
     Ok(db)
@@ -434,10 +445,7 @@ pub fn open_readwrite_hord_db_conn_rocks_db(
     _ctx: &Context,
 ) -> Result<DB, String> {
     let path = get_default_hord_db_file_path_rocks_db(&base_dir);
-    let mut opts = rocksdb::Options::default();
-    opts.create_if_missing(true);
-    opts.set_max_open_files(5000);
-    // opts.set_disable_auto_compactions(true);
+    let opts = rocks_db_default_options();
     let db = DB::open(&opts, path)
         .map_err(|e| format!("unable to open blocks_db: {}", e.to_string()))?;
     Ok(db)