From a381ca7ef80446c37101718e776a539f430ff354 Mon Sep 17 00:00:00 2001
From: Jan <jan.weber@avatic.de>
Date: Wed, 28 Jan 2026 11:21:00 +0100
Subject: [PATCH] Improved `removeOld` method in `BulkOperationRepository` to
 fix subquery limitations in MySQL and optimize deletion logic.

---
 .../bulk/BulkOperationRepository.java         | 47 ++++++++++---------
 1 file changed, 26 insertions(+), 21 deletions(-)

diff --git a/src/main/java/de/avatic/lcc/repositories/bulk/BulkOperationRepository.java b/src/main/java/de/avatic/lcc/repositories/bulk/BulkOperationRepository.java
index b11362c..d70deb3 100644
--- a/src/main/java/de/avatic/lcc/repositories/bulk/BulkOperationRepository.java
+++ b/src/main/java/de/avatic/lcc/repositories/bulk/BulkOperationRepository.java
@@ -69,14 +69,27 @@ public class BulkOperationRepository {
 
     @Transactional
     public void removeOld(Integer userId) {
-        // First, update sys_error records to set bulk_operation_id to NULL
-        // for bulk operations that will be deleted (all but the 10 newest for the current user)
-
-        // Build subquery to get the 10 newest operations
-        String newestSubquery = "SELECT id FROM bulk_operation WHERE user_id = ? AND state NOT IN ('SCHEDULED', 'PROCESSING') ORDER BY created_at DESC ";
-        String newestWithLimit = newestSubquery + dialectProvider.buildPaginationClause(10, 0);
+        // First, fetch the IDs of the 10 newest operations to keep
+        // (MySQL doesn't support LIMIT in IN/NOT IN subqueries)
+        String fetchNewestSql = "SELECT id FROM bulk_operation WHERE user_id = ? AND state NOT IN ('SCHEDULED', 'PROCESSING') ORDER BY created_at DESC " +
+            dialectProvider.buildPaginationClause(10, 0);
         Object[] paginationParams = dialectProvider.getPaginationParameters(10, 0);
+        Object[] fetchParams = new Object[]{userId, paginationParams[0], paginationParams[1]};
 
+        List<Integer> newestIds = jdbcTemplate.queryForList(fetchNewestSql, Integer.class, fetchParams);
+
+        // If there are 10 or fewer operations, nothing to delete
+        if (newestIds.size() <= 10) {
+            return;
+        }
+
+        // Build comma-separated list of IDs to keep
+        String idsToKeep = newestIds.stream()
+                    .map(String::valueOf)
+                    .reduce((a, b) -> a + "," + b)
+                    .orElse("0");
+
+        // Update sys_error records to set bulk_operation_id to NULL for operations that will be deleted
         String updateErrorsSql = String.format("""
                 UPDATE sys_error
                 SET bulk_operation_id = NULL
@@ -84,29 +97,21 @@ public class BulkOperationRepository {
                     SELECT id FROM bulk_operation
                     WHERE user_id = ?
                     AND state NOT IN ('SCHEDULED', 'PROCESSING')
-                    AND id NOT IN (
-                        %s
-                    )
+                    AND id NOT IN (%s)
                 )
-                """, newestWithLimit);
+                """, idsToKeep);
 
-        // Combine params: userId for outer query, userId + pagination params for subquery
-        Object[] updateParams = new Object[]{userId, userId, paginationParams[0], paginationParams[1]};
-        jdbcTemplate.update(updateErrorsSql, updateParams);
+        jdbcTemplate.update(updateErrorsSql, userId);
 
-        // Then delete the old bulk_operation entries (keeping only the 10 newest for the current user)
+        // Delete the old bulk_operation entries (keeping only the 10 newest for the current user)
         String deleteBulkSql = String.format("""
                 DELETE FROM bulk_operation
                 WHERE user_id = ?
                 AND state NOT IN ('SCHEDULED', 'PROCESSING')
-                AND id NOT IN (
-                    %s
-                )
-                """, newestWithLimit);
+                AND id NOT IN (%s)
+                """, idsToKeep);
 
-        // Combine params: userId for WHERE clause, userId + pagination params for subquery
-        Object[] deleteParams = new Object[]{userId, userId, paginationParams[0], paginationParams[1]};
-        jdbcTemplate.update(deleteBulkSql, deleteParams);
+        jdbcTemplate.update(deleteBulkSql, userId);
     }
 
     @Transactional