Tweak backfilling the blocked builds

guix-data-service/model/blocked-builds.scm

@@ -291,18 +291,18 @@ FROM latest_build_status
          (map car (exec-query conn query '()))))
     (chunk-for-each!
      (lambda (ids)
-       (with-postgresql-transaction
-        conn
-        (lambda (conn)
-          (exec-query
-           conn
-           "LOCK TABLE blocked_builds IN SHARE MODE")
+       (with-time-logging "processing chunk"
+         (with-postgresql-transaction
+          conn
+          (lambda (conn)
+            (exec-query
+             conn
+             "LOCK TABLE blocked_builds IN SHARE MODE")
 
-          (handle-populating-blocked-builds-for-build-failures
-           conn
-           (map string->number ids))
-          (simple-format #t "processed chunk...\n"))))
-     1000
+            (handle-populating-blocked-builds-for-build-failures
+             conn
+             (map string->number ids))))))
+     500
      build-ids)))
 
 (define* (select-blocking-builds conn revision-commit