commit the delete query for each user in the loop to reduce lock time

packages/db/migrations/0181.do.batch_delete_trash_items.sql

@@ -4,7 +4,9 @@
 
 BEGIN;
 
-CREATE OR REPLACE FUNCTION batch_delete_trash_items()
+CREATE OR REPLACE PROCEDURE batch_delete_trash_items(
+    minimum_items INT
+)
 RETURNS VOID AS $$
 DECLARE
     user_record RECORD;
@@ -17,14 +19,32 @@ DECLARE
         status = 'ACTIVE';
 BEGIN
     FOR user_record IN user_cursor LOOP
+        BEGIN;
+        
         -- For Row Level Security
         PERFORM omnivore.set_claims(user_record.id, 'omnivore_user');
 
+        -- keep the minimum number of items in trash
         DELETE FROM omnivore.library_item
         WHERE
             user_id = user_record.id
             AND state = 'DELETED'
-            AND deleted_at < NOW() - INTERVAL '14 days';
+            AND deleted_at < NOW() - INTERVAL '14 days'
+            AND id NOT IN (
+                SELECT
+                    id
+                FROM
+                    omnivore.library_item
+                WHERE
+                    user_id = user_record.id
+                    AND state = 'DELETED'
+                    AND deleted_at < NOW() - INTERVAL '14 days'
+                ORDER BY
+                    deleted_at DESC
+                LIMIT minimum_items
+            );
+
+        COMMIT;
     END LOOP;
 END;
 $$ LANGUAGE plpgsql;

packages/db/migrations/0181.undo.batch_delete_trash_items.sql

@@ -4,6 +4,6 @@
 
 BEGIN;
 
-DROP FUNCTION IF EXISTS batch_delete_trash_items();
+DROP PROCEDURE IF EXISTS batch_delete_trash_items();
 
 COMMIT;