From 3ee44245563f6293f1df64c3ca28e31119210394 Mon Sep 17 00:00:00 2001
From: Marcel <marcel@familienarchiv>
Date: Fri, 17 Apr 2026 21:21:12 +0200
Subject: [PATCH] perf(ocr): resolve person names in single batch query in
 getTrainingInfo

Replace the per-run getById loop with a single getAllById call on distinct
person IDs, eliminating the N+1 query when training history contains multiple
sender model runs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 .../service/OcrTrainingService.java           | 17 +++++-----
 .../service/OcrTrainingServiceTest.java       | 32 +++++++++++++++++++
 2 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/backend/src/main/java/org/raddatz/familienarchiv/service/OcrTrainingService.java b/backend/src/main/java/org/raddatz/familienarchiv/service/OcrTrainingService.java
index f61fcb46..08e9706a 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/service/OcrTrainingService.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/service/OcrTrainingService.java
@@ -202,16 +202,15 @@ public class OcrTrainingService {
         List<OcrTrainingRun> recentRuns = trainingRunRepository.findTop20ByOrderByCreatedAtDesc();
         OcrTrainingRun lastRun = recentRuns.isEmpty() ? null : recentRuns.get(0);
 
+        List<UUID> distinctPersonIds = recentRuns.stream()
+                .map(OcrTrainingRun::getPersonId)
+                .filter(Objects::nonNull)
+                .distinct()
+                .collect(java.util.stream.Collectors.toList());
         Map<String, String> personNames = new HashMap<>();
-        for (OcrTrainingRun run : recentRuns) {
-            if (run.getPersonId() != null && !personNames.containsKey(run.getPersonId().toString())) {
-                try {
-                    personNames.put(run.getPersonId().toString(),
-                            personService.getById(run.getPersonId()).getDisplayName());
-                } catch (Exception e) {
-                    log.debug("Could not resolve display name for person {}: {}", run.getPersonId(), e.getMessage());
-                }
-            }
+        if (!distinctPersonIds.isEmpty()) {
+            personService.getAllById(distinctPersonIds)
+                    .forEach(p -> personNames.put(p.getId().toString(), p.getDisplayName()));
         }
 
         return new TrainingInfoResponse(
diff --git a/backend/src/test/java/org/raddatz/familienarchiv/service/OcrTrainingServiceTest.java b/backend/src/test/java/org/raddatz/familienarchiv/service/OcrTrainingServiceTest.java
index a887a490..2e09eb69 100644
--- a/backend/src/test/java/org/raddatz/familienarchiv/service/OcrTrainingServiceTest.java
+++ b/backend/src/test/java/org/raddatz/familienarchiv/service/OcrTrainingServiceTest.java
@@ -4,6 +4,7 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.raddatz.familienarchiv.exception.DomainException;
 import org.raddatz.familienarchiv.model.OcrTrainingRun;
+import org.raddatz.familienarchiv.model.Person;
 import org.raddatz.familienarchiv.model.TrainingStatus;
 import org.raddatz.familienarchiv.model.TranscriptionBlock;
 import org.raddatz.familienarchiv.repository.OcrTrainingRunRepository;
@@ -232,6 +233,37 @@ class OcrTrainingServiceTest {
                 run.getStatus() == TrainingStatus.FAILED && run.getErrorMessage() != null));
     }
 
+    // ─── getTrainingInfo: batch person name resolution ────────────────────────
+
+    @Test
+    void getTrainingInfo_resolves_person_names_in_single_batch_call() {
+        UUID personA = UUID.randomUUID();
+        UUID personB = UUID.randomUUID();
+        List<OcrTrainingRun> runs = List.of(
+                OcrTrainingRun.builder().id(UUID.randomUUID()).status(TrainingStatus.DONE)
+                        .personId(personA).blockCount(5).documentCount(1).modelName("sender_a").build(),
+                OcrTrainingRun.builder().id(UUID.randomUUID()).status(TrainingStatus.DONE)
+                        .personId(personB).blockCount(5).documentCount(1).modelName("sender_b").build(),
+                OcrTrainingRun.builder().id(UUID.randomUUID()).status(TrainingStatus.DONE)
+                        .personId(personA).blockCount(5).documentCount(1).modelName("sender_a").build()
+        );
+        when(runRepository.findTop20ByOrderByCreatedAtDesc()).thenReturn(runs);
+        when(exportService.queryEligibleBlocks()).thenReturn(List.of());
+
+        Person pa = Person.builder().id(personA).firstName("Anna").lastName("Müller").build();
+        Person pb = Person.builder().id(personB).firstName("Karl").lastName("Bauer").build();
+        when(personService.getAllById(argThat(ids -> ids.size() == 2 && ids.containsAll(List.of(personA, personB)))))
+                .thenReturn(List.of(pa, pb));
+        when(healthClient.isHealthy()).thenReturn(true);
+
+        OcrTrainingService.TrainingInfoResponse info = service.getTrainingInfo();
+
+        verify(personService, never()).getById(any());
+        verify(personService, times(1)).getAllById(any());
+        assertThat(info.personNames()).containsKey(personA.toString());
+        assertThat(info.personNames()).containsKey(personB.toString());
+    }
+
     // ─── Orphan recovery ──────────────────────────────────────────────────────
 
     @Test