feat(mito): Implement file cache (GreptimeTeam#3022)

* feat: recover cache

* feat: moka features

* test: tests for file cache

* chore: suppress warninig

* fix: parse_inde_key consider suffix

* feat: update cache

* feat: expose cache file path

* feat: use cache_path in test

src/mito2/Cargo.toml

@@ -43,7 +43,7 @@ index.workspace = true
 lazy_static = "1.4"
 log-store = { workspace = true, optional = true }
 memcomparable = "0.2"
-moka = { workspace = true, features = ["sync"] }
+moka = { workspace = true, features = ["sync", "future"] }
 num_cpus = "1.13"
 object-store.workspace = true
 parquet = { workspace = true, features = ["async"] }

src/mito2/src/cache.rs

@@ -15,6 +15,9 @@
 //! Cache for the engine.
 
 mod cache_size;
+// TODO(yingwen): Remove this after the write cache is ready.
+#[allow(unused)]
+pub(crate) mod file_cache;
 #[cfg(test)]
 pub(crate) mod test_util;
 
@@ -38,6 +41,8 @@ const SST_META_TYPE: &str = "sst_meta";
 const VECTOR_TYPE: &str = "vector";
 // Metrics type key for pages.
 const PAGE_TYPE: &str = "page";
+// Metrics type key for files on the local store.
+const FILE_TYPE: &str = "file";
 
 /// Manages cached data for the engine.
 pub struct CacheManager {