diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 8861274a2..008451666 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -258,6 +258,86 @@ StorePath Store::addToStore(
     return addToStoreFromDump(*source, name, method, hashAlgo, repair, references);
 }
 
+void Store::addMultipleToStore(
+    std::vector<std::pair<ValidPathInfo, std::unique_ptr<Source>>> & pathsToCopy,
+    Activity & act,
+    RepairFlag repair,
+    CheckSigsFlag checkSigs)
+{
+    std::atomic<size_t> nrDone{0};
+    std::atomic<size_t> nrFailed{0};
+    std::atomic<uint64_t> bytesExpected{0};
+    std::atomic<uint64_t> nrRunning{0};
+
+    using PathWithInfo = std::pair<ValidPathInfo, std::unique_ptr<Source>>;
+
+    std::map<StorePath, PathWithInfo*> infosMap;
+    StorePathSet storePathsToAdd;
+    for (auto & thingToAdd : pathsToCopy) {
+        infosMap.insert_or_assign(thingToAdd.first.path, &thingToAdd);
+        storePathsToAdd.insert(thingToAdd.first.path);
+    }
+
+    auto showProgress = [&]() {
+        act.progress(nrDone, pathsToCopy.size(), nrRunning, nrFailed);
+    };
+
+    ThreadPool pool;
+
+    processGraph<StorePath>(pool,
+        storePathsToAdd,
+
+        [&](const StorePath & path) {
+            auto & [info, source] = *infosMap.at(path);
+            /* auto storePathForDst = info.storePath; */
+            /* if (info->ca && info->references.empty()) { */
+            /*     storePathForDst = dstStore.makeFixedOutputPathFromCA(storePath.name(), *info->ca); */
+            /*     if (dstStore.storeDir == srcStore.storeDir) */
+            /*         assert(storePathForDst == storePath); */
+            /*     if (storePathForDst != storePath) */
+            /*         debug("replaced path '%s' to '%s' for substituter '%s'", */
+            /*             srcStore.printStorePath(storePath), */
+            /*             dstStore.printStorePath(storePathForDst), */
+            /*             dstStore.getUri()); */
+            /* } */
+            /* pathsMap.insert_or_assign(storePath, storePathForDst); */
+
+            if (isValidPath(info.path)) {
+                nrDone++;
+                showProgress();
+                return StorePathSet();
+            }
+
+            bytesExpected += info.narSize;
+            act.setExpected(actCopyPath, bytesExpected);
+
+            return info.references;
+        },
+
+        [&](const StorePath & path) {
+            checkInterrupt();
+
+            auto & [info, source] = *infosMap.at(path);
+
+            if (!isValidPath(info.path)) {
+                MaintainCount<decltype(nrRunning)> mc(nrRunning);
+                showProgress();
+                try {
+                    addToStore(info, *source, repair, checkSigs);
+                } catch (Error &e) {
+                    nrFailed++;
+                    if (!settings.keepGoing)
+                        throw e;
+                    printMsg(lvlError, "could not copy %s: %s", printStorePath(path), e.what());
+                    showProgress();
+                    return;
+                }
+            }
+
+            nrDone++;
+            showProgress();
+        });
+}
 
 void Store::addMultipleToStore(
     Source & source,
@@ -998,106 +1078,39 @@ std::map<StorePath, StorePath> copyPaths(
 
     Activity act(*logger, lvlInfo, actCopyPaths, fmt("copying %d paths", missing.size()));
 
-    auto sorted = srcStore.topoSortPaths(missing);
-    std::reverse(sorted.begin(), sorted.end());
+    /* auto sorted = srcStore.topoSortPaths(missing); */
+    /* std::reverse(sorted.begin(), sorted.end()); */
 
-    auto source = sinkToSource([&](Sink & sink) {
-        sink << sorted.size();
-        for (auto & storePath : sorted) {
-            auto srcUri = srcStore.getUri();
-            auto dstUri = dstStore.getUri();
-            auto storePathS = srcStore.printStorePath(storePath);
-            Activity act(*logger, lvlInfo, actCopyPath,
-                makeCopyPathMessage(srcUri, dstUri, storePathS),
-                {storePathS, srcUri, dstUri});
-            PushActivity pact(act.id);
+    /* auto source = sinkToSource([&](Sink & sink) { */
+    /*     sink << sorted.size(); */
+    /*     for (auto & storePath : sorted) { */
+    /*         auto srcUri = srcStore.getUri(); */
+    /*         auto dstUri = dstStore.getUri(); */
+    /*         auto storePathS = srcStore.printStorePath(storePath); */
+    /*         Activity act(*logger, lvlInfo, actCopyPath, */
+    /*             makeCopyPathMessage(srcUri, dstUri, storePathS), */
+    /*             {storePathS, srcUri, dstUri}); */
+    /*         PushActivity pact(act.id); */
 
-            auto info = srcStore.queryPathInfo(storePath);
-            info->write(sink, srcStore, 16);
-            srcStore.narFromPath(storePath, sink);
-        }
-    });
+    /*         auto info = srcStore.queryPathInfo(storePath); */
+    /*         info->write(sink, srcStore, 16); */
+    /*         srcStore.narFromPath(storePath, sink); */
+    /*     } */
+    /* }); */
 
-    dstStore.addMultipleToStore(*source, repair, checkSigs);
+    std::vector<std::pair<ValidPathInfo, std::unique_ptr<Source>>> pathsToCopy;
+
+    for (auto & missingPath : missing) {
+        auto info = srcStore.queryPathInfo(missingPath);
+        auto source = sinkToSource([&](Sink & sink) {
+            srcStore.narFromPath(missingPath, sink);
+        });
+        pathsToCopy.push_back(std::pair{*info, std::move(source)});
+    }
+
+    dstStore.addMultipleToStore(pathsToCopy, act, repair, checkSigs);
 
     #if 0
-    std::atomic<size_t> nrDone{0};
-    std::atomic<size_t> nrFailed{0};
-    std::atomic<uint64_t> bytesExpected{0};
-    std::atomic<uint64_t> nrRunning{0};
-
-    auto showProgress = [&]() {
-        act.progress(nrDone, missing.size(), nrRunning, nrFailed);
-    };
-
-    ThreadPool pool;
-
-    processGraph<StorePath>(pool,
-        StorePathSet(missing.begin(), missing.end()),
-
-        [&](const StorePath & storePath) {
-            auto info = srcStore.queryPathInfo(storePath);
-            auto storePathForDst = storePath;
-            if (info->ca && info->references.empty()) {
-                storePathForDst = dstStore.makeFixedOutputPathFromCA(storePath.name(), *info->ca);
-                if (dstStore.storeDir == srcStore.storeDir)
-                    assert(storePathForDst == storePath);
-                if (storePathForDst != storePath)
-                    debug("replaced path '%s' to '%s' for substituter '%s'",
-                        srcStore.printStorePath(storePath),
-                        dstStore.printStorePath(storePathForDst),
-                        dstStore.getUri());
-            }
-            pathsMap.insert_or_assign(storePath, storePathForDst);
-
-            if (dstStore.isValidPath(storePath)) {
-                nrDone++;
-                showProgress();
-                return StorePathSet();
-            }
-
-            bytesExpected += info->narSize;
-            act.setExpected(actCopyPath, bytesExpected);
-
-            return info->references;
-        },
-
-        [&](const StorePath & storePath) {
-            checkInterrupt();
-
-            auto info = srcStore.queryPathInfo(storePath);
-
-            auto storePathForDst = storePath;
-            if (info->ca && info->references.empty()) {
-                storePathForDst = dstStore.makeFixedOutputPathFromCA(storePath.name(), *info->ca);
-                if (dstStore.storeDir == srcStore.storeDir)
-                    assert(storePathForDst == storePath);
-                if (storePathForDst != storePath)
-                    debug("replaced path '%s' to '%s' for substituter '%s'",
-                        srcStore.printStorePath(storePath),
-                        dstStore.printStorePath(storePathForDst),
-                        dstStore.getUri());
-            }
-            pathsMap.insert_or_assign(storePath, storePathForDst);
-
-            if (!dstStore.isValidPath(storePathForDst)) {
-                MaintainCount<decltype(nrRunning)> mc(nrRunning);
-                showProgress();
-                try {
-                    copyStorePath(srcStore, dstStore, storePath, repair, checkSigs);
-                } catch (Error &e) {
-                    nrFailed++;
-                    if (!settings.keepGoing)
-                        throw e;
-                    printMsg(lvlError, "could not copy %s: %s", dstStore.printStorePath(storePath), e.what());
-                    showProgress();
-                    return;
-                }
-            }
-
-            nrDone++;
-            showProgress();
-        });
     #endif
 
     return pathsMap;
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 0c8a4db56..d934979cf 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "nar-info.hh"
 #include "realisation.hh"
 #include "path.hh"
 #include "derived-path.hh"
@@ -364,6 +365,12 @@ public:
         Source & source,
         RepairFlag repair = NoRepair,
         CheckSigsFlag checkSigs = CheckSigs);
+    virtual void addMultipleToStore(
+        std::vector<std::pair<ValidPathInfo, std::unique_ptr<Source>>> & pathsToCopy,
+        Activity & act,
+        RepairFlag repair = NoRepair,
+        CheckSigsFlag checkSigs = CheckSigs
+    );
 
     /* Copy the contents of a path to the store and register the
        validity the resulting path.  The resulting path is returned.