Repository: risingwavelabs/risingwave
File: src/meta/src/rpc/metrics.rs (Rust)

Code before:
        ).unwrap();

        let total_object_size = register_int_gauge_with_registry!(
            "storage_total_object_size",
            "Total size of objects that includes dangling objects. Note that the metric is updated right before full GC. So subsequent full GC may reduce the actual value significantly, without updating the metric.",
            registry
        ).unwrap();

        let table_change_log_object_count = register_int_gauge_vec_with_registry!(
            "storage_table_change_log_object_count",
            "per table change log object count",
            &["table_id"],
            registry
        )
        .unwrap();

        let table_change_log_object_size = register_int_gauge_vec_with_registry!(
            "storage_table_change_log_object_size",
            "per table change log object size",
            &["table_id"],
            registry
        )
        .unwrap();

        let crossdb_changelog_min_epoch = register_int_gauge_vec_with_registry!(
            "crossdb_changelog_min_epoch",
            "min epoch currently retained in table change log",
            &["table_id"],
            registry
        )
        .unwrap();

        let time_travel_object_count = register_int_gauge_with_registry!(
            "storage_time_travel_object_count",
            "total number of objects that is referenced by time travel.",
            registry
        )
        .unwrap();

        let delta_log_count = register_int_gauge_with_registry!(
            "storage_delta_log_count",
            "total number of hummock version delta log",
            registry
        )
        .unwrap();

        let opts = histogram_opts!(
            "storage_version_checkpoint_latency",
            "hummock version checkpoint latency",
            exponential_buckets(0.1, 1.5, 20).unwrap()
        );

Review comment (suggestion):
Table change log is not dedicated for cross db query. May change  the name to `table_change_log_min_epoch`

Code after:
        ).unwrap();

        let total_object_size = register_int_gauge_with_registry!(
            "storage_total_object_size",
            "Total size of objects that includes dangling objects. Note that the metric is updated right before full GC. So subsequent full GC may reduce the actual value significantly, without updating the metric.",
            registry
        ).unwrap();

        let table_change_log_object_count = register_int_gauge_vec_with_registry!(
            "storage_table_change_log_object_count",
            "per table change log object count",
            &["table_id"],
            registry
        )
        .unwrap();

        let table_change_log_object_size = register_int_gauge_vec_with_registry!(
            "storage_table_change_log_object_size",
            "per table change log object size",
            &["table_id"],
            registry
        )
        .unwrap();

        let table_change_log_min_epoch = register_int_gauge_vec_with_registry!(
            "storage_table_change_log_min_epoch",
            "min epoch currently retained in table change log",
            &["table_id"],
            registry
        )
        .unwrap();

        let time_travel_object_count = register_int_gauge_with_registry!(
            "storage_time_travel_object_count",
            "total number of objects that is referenced by time travel.",
            registry
        )
        .unwrap();

        let delta_log_count = register_int_gauge_with_registry!(
            "storage_delta_log_count",
            "total number of hummock version delta log",
            registry
        )
        .unwrap();

        let opts = histogram_opts!(
            "storage_version_checkpoint_latency",
            "hummock version checkpoint latency",
            exponential_buckets(0.1, 1.5, 20).unwrap()
        );