Attempt to avoid issues with the guix-daemon WAL

guix-data-service/jobs/load-new-guix-revision.scm

@@ -1445,6 +1445,16 @@
       (lambda (filename)
         (put-message channel filename))))
 
+  (define lock-num
+    ;; I'm seeing problems with the guix-dameon WAL growing excessively, which
+    ;; I think is happening when processing revivions involving lots of new
+    ;; derivations. So limit the concurrency here in the hope that this'll
+    ;; help.
+    (with-time-logging "getting 'inferior-package-derivations lock"
+      (lock-advisory-session-lock
+       conn
+       'inferior-package-derivations)))
+
   (simple-format #t "debug: extract-information-from: ~A\n" store-path)
 
   (letpar& ((inferior-lint-checkers-and-warnings-data
@@ -1524,6 +1534,7 @@
                                                   pkg-to-replacement-hash-table))))))))
 
     (destroy-resource-pool inf-and-store-pool)
+    (unlock-advisory-session-lock conn lock-num)
 
     (simple-format
      #t "debug: finished loading information from inferior\n")