diff --git a/src/libstore/build/derivation-goal.hh b/src/libstore/build/derivation-goal.hh
index 4976207e0..8ee0be9e1 100644
--- a/src/libstore/build/derivation-goal.hh
+++ b/src/libstore/build/derivation-goal.hh
@@ -40,9 +40,8 @@ struct InitialOutput {
     std::optional<InitialOutputStatus> known;
 };
 
-class DerivationGoal : public Goal
+struct DerivationGoal : public Goal
 {
-private:
     /* Whether to use an on-disk .drv file. */
     bool useDerivation;
 
@@ -246,7 +245,6 @@ private:
 
     friend struct RestrictedStore;
 
-public:
     DerivationGoal(const StorePath & drvPath,
         const StringSet & wantedOutputs, Worker & worker,
         BuildMode buildMode = bmNormal);
@@ -264,17 +262,11 @@ public:
 
     void work() override;
 
-    StorePath getDrvPath()
-    {
-        return drvPath;
-    }
-
     /* Add wanted outputs to an already existing derivation goal. */
     void addWantedOutputs(const StringSet & outputs);
 
     BuildResult getResult() { return result; }
 
-private:
     /* The states. */
     void getDerivation();
     void loadDerivation();
@@ -318,8 +310,6 @@ private:
     /* Run the builder's process. */
     void runChild();
 
-    friend int childEntry(void *);
-
     /* Check that the derivation outputs all exist and register them
        as valid. */
     void registerOutputs();
diff --git a/src/libstore/build/local-store-build.cc b/src/libstore/build/local-store-build.cc
index a05fb5805..c91cda2fd 100644
--- a/src/libstore/build/local-store-build.cc
+++ b/src/libstore/build/local-store-build.cc
@@ -5,25 +5,10 @@
 
 namespace nix {
 
-static void primeCache(Store & store, const std::vector<StorePathWithOutputs> & paths)
-{
-    StorePathSet willBuild, willSubstitute, unknown;
-    uint64_t downloadSize, narSize;
-    store.queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
-
-    if (!willBuild.empty() && 0 == settings.maxBuildJobs && getMachines().empty())
-        throw Error(
-            "%d derivations need to be built, but neither local builds ('--max-jobs') "
-            "nor remote builds ('--builders') are enabled", willBuild.size());
-}
-
-
 void LocalStore::buildPaths(const std::vector<StorePathWithOutputs> & drvPaths, BuildMode buildMode)
 {
     Worker worker(*this);
 
-    primeCache(*this, drvPaths);
-
     Goals goals;
     for (auto & path : drvPaths) {
         if (path.path.isDerivation())
@@ -44,9 +29,8 @@ void LocalStore::buildPaths(const std::vector<StorePathWithOutputs> & drvPaths,
                 ex = i->ex;
         }
         if (i->exitCode != Goal::ecSuccess) {
-            DerivationGoal * i2 = dynamic_cast<DerivationGoal *>(i.get());
-            if (i2) failed.insert(i2->getDrvPath());
-            else failed.insert(dynamic_cast<SubstitutionGoal *>(i.get())->getStorePath());
+            if (auto i2 = dynamic_cast<DerivationGoal *>(i.get())) failed.insert(i2->drvPath);
+            else if (auto i2 = dynamic_cast<SubstitutionGoal *>(i.get())) failed.insert(i2->storePath);
         }
     }
 
@@ -84,8 +68,6 @@ void LocalStore::ensurePath(const StorePath & path)
     /* If the path is already valid, we're done. */
     if (isValidPath(path)) return;
 
-    primeCache(*this, {{path}});
-
     Worker worker(*this);
     GoalPtr goal = worker.makeSubstitutionGoal(path);
     Goals goals = {goal};
diff --git a/src/libstore/build/substitution-goal.hh b/src/libstore/build/substitution-goal.hh
index 3ae9a9e6b..dee2cecbf 100644
--- a/src/libstore/build/substitution-goal.hh
+++ b/src/libstore/build/substitution-goal.hh
@@ -8,11 +8,8 @@ namespace nix {
 
 class Worker;
 
-class SubstitutionGoal : public Goal
+struct SubstitutionGoal : public Goal
 {
-    friend class Worker;
-
-private:
     /* The store path that should be realised through a substitute. */
     StorePath storePath;
 
@@ -56,7 +53,6 @@ private:
     /* Content address for recomputing store path */
     std::optional<ContentAddress> ca;
 
-public:
     SubstitutionGoal(const StorePath & storePath, Worker & worker, RepairFlag repair = NoRepair, std::optional<ContentAddress> ca = std::nullopt);
     ~SubstitutionGoal();
 
@@ -82,8 +78,6 @@ public:
     /* Callback used by the worker to write to the log. */
     void handleChildOutput(int fd, const string & data) override;
     void handleEOF(int fd) override;
-
-    StorePath getStorePath() { return storePath; }
 };
 
 }
diff --git a/src/libstore/build/worker.cc b/src/libstore/build/worker.cc
index 17c10cd71..1f8999a4b 100644
--- a/src/libstore/build/worker.cc
+++ b/src/libstore/build/worker.cc
@@ -207,7 +207,26 @@ void Worker::waitForAWhile(GoalPtr goal)
 
 void Worker::run(const Goals & _topGoals)
 {
-    for (auto & i : _topGoals) topGoals.insert(i);
+    std::vector<nix::StorePathWithOutputs> topPaths;
+
+    for (auto & i : _topGoals) {
+        topGoals.insert(i);
+        if (auto goal = dynamic_cast<DerivationGoal *>(i.get())) {
+            topPaths.push_back({goal->drvPath, goal->wantedOutputs});
+        } else if (auto goal = dynamic_cast<SubstitutionGoal *>(i.get())) {
+            topPaths.push_back({goal->storePath});
+        }
+    }
+
+    /* Call queryMissing() efficiently query substitutes. */
+    StorePathSet willBuild, willSubstitute, unknown;
+    uint64_t downloadSize, narSize;
+    store.queryMissing(topPaths, willBuild, willSubstitute, unknown, downloadSize, narSize);
+
+    if (!willBuild.empty() && 0 == settings.maxBuildJobs && getMachines().empty())
+        throw Error(
+            "%d derivations need to be built, but neither local builds ('--max-jobs') "
+            "nor remote builds ('--builders') are enabled", willBuild.size());
 
     debug("entered goal loop");