Re-enable cluster state transition optimization

Made side effects of replica resurrection bug more likely to be observed,
but not in itself a believed root cause of any issues.

1 files changed, 11 insertions, 1 deletions

diff --git a/storage/src/vespa/storage/distributor/bucketdbupdater.cpp b/storage/src/vespa/storage/distributor/bucketdbupdater.cpp
index b089d3ab83f..33fa80ab484 100644
--- a/storage/src/vespa/storage/distributor/bucketdbupdater.cpp
+++ b/storage/src/vespa/storage/distributor/bucketdbupdater.cpp
@@ -128,7 +128,7 @@ BucketDBUpdater::recheckBucketInfo(uint32_t nodeIdx,
 void
 BucketDBUpdater::removeSuperfluousBuckets(
         const lib::ClusterStateBundle& newState,
-        [[maybe_unused]] bool is_distribution_config_change)
+        bool is_distribution_config_change)
 {
     const bool move_to_read_only_db = shouldDeferStateEnabling();
     const char* up_states = _distributorComponent.getDistributor().getStorageNodeUpStates();
@@ -137,6 +137,16 @@ BucketDBUpdater::removeSuperfluousBuckets(
         const auto& oldClusterState(elem.second->getClusterState());
         const auto& new_cluster_state = newState.getDerivedClusterState(elem.first);
 
+        // Running a full DB sweep is expensive, so if the cluster state transition does
+        // not actually indicate that buckets should possibly be removed, we elide it entirely.
+        if (!is_distribution_config_change
+            && db_pruning_may_be_elided(oldClusterState, *new_cluster_state, up_states))
+        {
+            LOG(debug, "Eliding DB pruning for state transition '%s' -> '%s'",
+                oldClusterState.toString().c_str(), new_cluster_state->toString().c_str());
+            continue;
+        }
+
         auto& bucketDb(elem.second->getBucketDatabase());
         auto& readOnlyDb(_distributorComponent.getReadOnlyBucketSpaceRepo().get(elem.first).getBucketDatabase());