diff --git a/guix-data-service/jobs/load-new-guix-revision.scm b/guix-data-service/jobs/load-new-guix-revision.scm
index e1700ad..f9b35e9 100644
--- a/guix-data-service/jobs/load-new-guix-revision.scm
+++ b/guix-data-service/jobs/load-new-guix-revision.scm
@@ -1224,17 +1224,40 @@ SELECT 1 FROM derivation_source_file_nars WHERE derivation_source_file_id = $1"
               '()
               derivations)))
         (unless (null? input-derivations)
-          ;; Ensure all the input derivations exist
-          (chunk-for-each!
-           (lambda (chunk)
-             (insert-missing-derivations
-              postgresql-connection-pool
-              call-with-utility-thread
-              derivation-ids-hash-table
-              chunk
-              #:log-tag log-tag))
-           1000
-           input-derivations)))))
+          (let loop ((chunk '())
+                     (count 0)
+                     (rest input-derivations))
+            (if (null? rest)
+                (unless (null? chunk)
+                  (insert-missing-derivations
+                   postgresql-connection-pool
+                   call-with-utility-thread
+                   derivation-ids-hash-table
+                   chunk
+                   #:log-tag log-tag))
+                (if (= count 1000)
+                    (begin
+                      (simple-format #t "debug: inserting ~A input derivations\n"
+                                     count)
+                      (insert-missing-derivations
+                       postgresql-connection-pool
+                       call-with-utility-thread
+                       derivation-ids-hash-table
+                       chunk
+                       #:log-tag log-tag)
+                      (loop '()
+                            0
+                            rest))
+                    (let ((drv (car rest)))
+                      (if (hash-ref derivation-ids-hash-table
+                                    (derivation-file-name
+                                     drv))
+                          (loop chunk
+                                count
+                                (cdr rest))
+                          (loop (cons drv chunk)
+                                (+ 1 count)
+                                (cdr rest)))))))))))
 
   (let ((derivations
          derivation-ids
@@ -1739,6 +1762,38 @@ WHERE builder != 'builtin:download'
       (for-each fix-derivation
                 broken-derivations))))
 
+(define (flatten-derivation-graph derivations
+                                  derivation-ids-hash-table)
+  (define seen-hash-table
+    (make-hash-table))
+
+  (define (flatten-inputs derivation result)
+    (fold
+     (lambda (input result)
+       (let ((drv (derivation-input-derivation input)))
+         (if (or (hash-ref derivation-ids-hash-table
+                           (derivation-file-name drv))
+                 (hash-ref seen-hash-table
+                           drv))
+             result
+             (begin
+               (hash-set! seen-hash-table drv #t)
+               (cons drv
+                     (flatten-inputs drv result))))))
+     result
+     (derivation-inputs derivation)))
+
+  (reverse!
+   (fold
+    (lambda (derivation result)
+      (let ((flat-inputs
+             (flatten-inputs derivation
+                             result)))
+        (cons derivation
+              flat-inputs)))
+    '()
+    derivations)))
+
 (define* (derivation-file-names->derivation-ids postgresql-connection-pool
                                                 call-with-utility-thread
                                                 read-derivations/serialised
@@ -1777,12 +1832,21 @@ WHERE builder != 'builtin:download'
           (let ((chunk-counter 0))
             (chunk-for-each!
              (lambda (missing-derivation-file-names-chunk)
-               (let ((missing-derivations-chunk
-                      (read-derivations/serialised
-                       missing-derivation-file-names-chunk)))
+               (simple-format
+                #t "debug: derivation-file-names->derivation-ids: processing chunk ~A (~A)\n"
+                chunk-counter
+                log-tag)
+               (let* ((missing-derivations-chunk
+                       (read-derivations/serialised
+                        missing-derivation-file-names-chunk))
+                      (flat-missing-derivations
+                       (with-time-logging "flattening missing derivations"
+                         (flatten-derivation-graph
+                          missing-derivations-chunk
+                          derivation-ids-hash-table))))
                  (simple-format
-                  #t "debug: derivation-file-names->derivation-ids: processing chunk ~A (~A)\n"
-                  chunk-counter
+                  #t "debug: derivation-file-names->derivation-ids: processing ~A flat missing derivations (~A)\n"
+                  (length flat-missing-derivations)
                   log-tag)
                  (set! chunk-counter (+ 1 chunk-counter))
                  (insert-missing-derivations postgresql-connection-pool