feat: support cache for batch_get in CachedMetaKvBackend (#3277)

* feat: support cache for batch_get in CachedMetaKvBackend.

* add doc of CachedMetaKvBackend

* fix: cr

* fix: correct some words

* fix cr

config/frontend.example.toml

@@ -69,6 +69,13 @@ timeout = "3s"
 ddl_timeout = "10s"
 connect_timeout = "1s"
 tcp_nodelay = true
+# The configuration about the cache of the Metadata.
+# default: 100000
+metadata_cache_max_capacity = 100000
+# default: 10m
+metadata_cache_ttl = "10m"
+# default: 5m
+metadata_cache_tti = "5m"
 
 # Log options, see `standalone.example.toml`
 # [logging]

src/catalog/src/kvbackend.rs

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-pub use client::{CachedMetaKvBackend, MetaKvBackend};
+pub use client::{CachedMetaKvBackend, CachedMetaKvBackendBuilder, MetaKvBackend};
 
 mod client;
 mod manager;