Move backfilling in to the server module and use the connection pool

To avoid using the old PostgreSQL connection per thread code.

guix-data-service/model/guix-revision-package-derivation.scm

@@ -166,10 +166,8 @@ VALUES ($1, $2, $3, $4, $5)"
             (loop (append level-counts (list count))))))))
    system-ids-and-targets))
 
-(define (backfill-guix-revision-package-derivation-distribution-counts)
+(define (backfill-guix-revision-package-derivation-distribution-counts conn)
   (define revision-ids
-    (with-thread-postgresql-connection
-     (lambda (conn)
     (map
      car
      (exec-query
@@ -180,20 +178,17 @@ VALUES ($1, $2, $3, $4, $5)"
 EXCEPT
   SELECT guix_revision_id
   FROM guix_revision_package_derivation_distribution_counts
-ORDER BY id DESC")))))
+ORDER BY id DESC")))
 
-  (n-par-for-each
-   4
+  (for-each
    (lambda (revision-id)
      (simple-format #t "backfilling guix_revision_package_derivation_distribution_counts for revision ~A\n" revision-id)
-     (with-thread-postgresql-connection
-      (lambda (conn)
      (with-postgresql-transaction
       conn
       (lambda (conn)
         (insert-guix-revision-package-derivation-distribution-counts
          conn
-            revision-id))))))
+         revision-id))))
    revision-ids))
 
 (define* (get-sql-to-select-package-and-related-derivations-for-revision

guix-data-service/web/server.scm

@@ -35,6 +35,7 @@
   #:use-module (guix-data-service database)
   #:use-module (guix-data-service web controller)
   #:use-module (guix-data-service web util)
+  #:use-module (guix-data-service model guix-revision-package-derivation)
   #:export (%guix-data-service-metrics-registry
 
             start-guix-data-service-web-server))
@@ -120,6 +121,12 @@
 
                (resource-pool-default-timeout 5))
 
+            (spawn-fiber
+             (lambda ()
+               (with-resource-from-pool (connection-pool) conn
+                 (backfill-guix-revision-package-derivation-distribution-counts
+                  conn))))
+
             (let ((render-metrics
                    (make-render-metrics registry)))
 

scripts/guix-data-service.in

@@ -197,13 +197,6 @@
           (lambda (port)
             (simple-format port "~A\n" (getpid)))))
 
-      (call-with-new-thread
-       (lambda ()
-         (with-postgresql-connection-per-thread
-          "backfill"
-          (lambda ()
-            (backfill-guix-revision-package-derivation-distribution-counts)))))
-
       (start-substitute-query-threads)
 
       (call-with-new-thread