From 0ef0586b0d604c7111ad538318e461c9eb9f8e7e Mon Sep 17 00:00:00 2001
From: Mark Elvers <mark.elvers@tunbury.org>
Date: Wed, 26 Apr 2023 11:12:37 +0100
Subject: [PATCH] Prune one at a time up to the limit

---
 lib/db_store.ml | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/db_store.ml b/lib/db_store.ml
index 17978e33..b542e8f3 100644
--- a/lib/db_store.ml
+++ b/lib/db_store.ml
@@ -142,10 +142,9 @@ module Make (Raw : S.STORE) = struct
     in
     aux id
 
-  let prune_batch ?(log=ignore) t ~before limit =
-    let items = Dao.lru t.dao ~before limit in
+  let prune_lru ?(log=ignore) t ~before =
+    let items = Dao.lru t.dao ~before 1 in
     let n = List.length items in
-    Log.info (fun f -> f "Pruning %d items (of %d requested)" n limit);
     items |> Lwt_list.iter_s (fun id ->
         log id;
         Raw.delete t.raw id >|= fun () ->
@@ -155,16 +154,18 @@ module Make (Raw : S.STORE) = struct
     Lwt.return n
 
   let prune ?log t ~before limit =
+    Log.info (fun f -> f "Pruning %d items" limit);
     let rec aux acc limit =
       if limit = 0 then Lwt.return acc  (* Pruned everything we wanted to *)
       else (
-        prune_batch ?log t ~before limit >>= function
+        prune_lru ?log t ~before >>= function
         | 0 -> Lwt.return acc           (* Nothing left to prune *)
         | n -> aux (acc + n) (limit - n)
       )
     in
     aux 0 limit >>= fun n ->
     Raw.complete_deletes t.raw >>= fun () ->
+    Log.info (fun f -> f "Pruned %d items" n);
     Lwt.return n
 
   let wrap raw =