Use a single level hash_map with a compund key.

3 files changed, 25 insertions, 32 deletions

diff --git a/storage/src/vespa/storage/distributor/distributor_stripe.cpp b/storage/src/vespa/storage/distributor/distributor_stripe.cpp
index b686c6bc80c..243b3c5ecb2 100644
--- a/storage/src/vespa/storage/distributor/distributor_stripe.cpp
+++ b/storage/src/vespa/storage/distributor/distributor_stripe.cpp
@@ -604,11 +604,9 @@ PerNodeBucketSpacesStats
 toBucketSpacesStats(const NodeMaintenanceStatsTracker &maintenanceStats)
 {
     PerNodeBucketSpacesStats result;
-    for (const auto &nodeEntry : maintenanceStats.perNodeStats()) {
-        for (const auto &bucketSpaceEntry : nodeEntry.second) {
-            auto bucketSpace = document::FixedBucketSpaces::to_string(bucketSpaceEntry.first);
-            result[nodeEntry.first][bucketSpace] = toBucketSpaceStats(bucketSpaceEntry.second);
-        }
+    for (const auto &entry : maintenanceStats.perNodeStats()) {
+        auto bucketSpace = document::FixedBucketSpaces::to_string(entry.first.bucketSpace());
+        result[entry.first.node()][bucketSpace] = toBucketSpaceStats(entry.second);
     }
     return result;
 }
diff --git a/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.cpp b/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.cpp
index 62ba3742627..b10f5abd0f1 100644
--- a/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.cpp
+++ b/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.cpp
@@ -9,35 +9,15 @@ namespace storage::distributor {
 
 const NodeMaintenanceStats NodeMaintenanceStatsTracker::_emptyNodeMaintenanceStats;
 
-namespace {
-
-void
-merge_bucket_spaces_stats(NodeMaintenanceStatsTracker::BucketSpacesStats& dest,
-                          const NodeMaintenanceStatsTracker::BucketSpacesStats& src)
-{
-    for (const auto& entry : src) {
-        auto bucket_space = entry.first;
-        dest[bucket_space].merge(entry.second);
-    }
-}
-
-}
-
 NodeMaintenanceStats &
 NodeMaintenanceStatsTracker::stats(uint16_t node, document::BucketSpace bucketSpace) {
-    return _node_stats[node][bucketSpace];
+    return _node_stats[BucketSpaceAndNode(node, bucketSpace)];
 }
 
 const NodeMaintenanceStats &
 NodeMaintenanceStatsTracker::stats(uint16_t node, document::BucketSpace bucketSpace) const noexcept {
-    auto nodeItr = _node_stats.find(node);
-    if (nodeItr != _node_stats.end()) {
-        auto bucketSpaceItr = nodeItr->second.find(bucketSpace);
-        if (bucketSpaceItr != nodeItr->second.end()) {
-            return bucketSpaceItr->second;
-        }
-    }
-    return _emptyNodeMaintenanceStats;
+    auto nodeItr = _node_stats.find(BucketSpaceAndNode(node, bucketSpace));
+    return (nodeItr != _node_stats.end()) ? nodeItr->second : _emptyNodeMaintenanceStats;
 }
 
 const NodeMaintenanceStats&
@@ -55,8 +35,8 @@ void
 NodeMaintenanceStatsTracker::merge(const NodeMaintenanceStatsTracker& rhs)
 {
     for (const auto& entry : rhs._node_stats) {
-        auto node_index = entry.first;
-        merge_bucket_spaces_stats(_node_stats[node_index], entry.second);
+        auto key = entry.first;
+        _node_stats[key].merge(entry.second);
     }
     _max_observed_time_since_last_gc = std::max(_max_observed_time_since_last_gc,
                                                 rhs._max_observed_time_since_last_gc);
diff --git a/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.h b/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.h
index 1d3423b2716..a5cb12de9a4 100644
--- a/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.h
+++ b/storage/src/vespa/storage/distributor/maintenance/node_maintenance_stats_tracker.h
@@ -51,8 +51,23 @@ std::ostream& operator<<(std::ostream&, const NodeMaintenanceStats&);
 class NodeMaintenanceStatsTracker
 {
 public:
-    using BucketSpacesStats = vespalib::hash_map<document::BucketSpace, NodeMaintenanceStats, document::BucketSpace::hash>;
-    using PerNodeStats = vespalib::hash_map<uint16_t, BucketSpacesStats>;
+    class BucketSpaceAndNode {
+    public:
+        BucketSpaceAndNode(uint16_t node_in, document::BucketSpace bucketSpace_in) noexcept
+            : _bucketSpace(bucketSpace_in),
+              _node(node_in)
+        {}
+        uint32_t hash() const noexcept { return (uint32_t(_node) << 2) | (_bucketSpace.getId() & 0x3); }
+        bool operator == (const BucketSpaceAndNode & b) const noexcept {
+            return (_bucketSpace == b._bucketSpace) && (_node == b._node);
+        }
+        document::BucketSpace bucketSpace() const noexcept { return _bucketSpace; }
+        uint16_t node() const noexcept { return _node; }
+    private:
+        document::BucketSpace _bucketSpace;
+        uint16_t              _node;
+    };
+    using PerNodeStats = vespalib::hash_map<BucketSpaceAndNode, NodeMaintenanceStats>;
 
 private:
     PerNodeStats         _node_stats;