chore(cubestore): Reset gauge metrics on shutdown (#7447)

Author: ovr

rust/cubestore/cubestore/src/cachestore/cache_rocksstore.rs

@@ -352,7 +352,15 @@ impl RocksCacheStore {
         Ok(())
     }
 
+    fn send_zero_gauge_stats(&self) {
+        app_metrics::CACHESTORE_ROCKSDB_ESTIMATE_LIVE_DATA_SIZE.report(0);
+        app_metrics::CACHESTORE_ROCKSDB_LIVE_SST_FILES_SIZE.report(0);
+        app_metrics::CACHESTORE_ROCKSDB_CF_DEFAULT_SIZE.report(0);
+    }
+
     pub async fn stop_processing_loops(&self) {
+        self.send_zero_gauge_stats();
+
         self.cache_eviction_manager.stop_processing_loops();
         self.upload_loop.stop();
         self.metrics_loop.stop();

rust/cubestore/cubestore/src/cachestore/scheduler.rs

@@ -2,7 +2,7 @@ use crate::cachestore::CacheStore;
 use crate::config::ConfigObj;
 use crate::metastore::MetaStoreEvent;
 use crate::shared::deadline_queue::DeadlineQueue;
-use crate::CubeError;
+use crate::{app_metrics, CubeError};
 use datafusion::cube_ext;
 use log::error;
 use std::sync::Arc;
@@ -130,7 +130,13 @@ impl CacheStoreSchedulerImpl {
         }
     }
 
+    fn send_zero_gauge_stats(&self) {
+        app_metrics::CACHESTORE_SCHEDULER_GC_QUEUE.report(0);
+    }
+
     pub fn stop_processing_loops(&self) -> Result<(), CubeError> {
+        self.send_zero_gauge_stats();
+
         self.cancel_token.cancel();
         Ok(())
     }

rust/cubestore/cubestore/src/sql/cache.rs

@@ -209,6 +209,13 @@ impl SqlResultCache {
     }
 }
 
+impl Drop for SqlResultCache {
+    fn drop(&mut self) {
+        app_metrics::DATA_QUERIES_CACHE_SIZE.report(0);
+        app_metrics::DATA_QUERIES_CACHE_WEIGHT.report(0);
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use crate::queryplanner::serialized_plan::SerializedPlan;