backend/src/main/java/org/raddatz/familienarchiv/service/OcrTrainingService.java

@@ -13,11 +13,13 @@ import org.springframework.boot.context.event.ApplicationReadyEvent;
 import org.springframework.context.event.EventListener;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
+import org.springframework.transaction.support.TransactionTemplate;
 
 import java.io.ByteArrayOutputStream;
 import java.time.Instant;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.UUID;
 
 @Service
@@ -31,6 +33,7 @@ public class OcrTrainingService {
     private final OcrClient ocrClient;
     private final OcrHealthClient ocrHealthClient;
     private final TranscriptionBlockRepository blockRepository;
+    private final TransactionTemplate txTemplate;
 
     public record TrainingInfoResponse(
             int availableBlocks,
@@ -46,8 +49,10 @@ public class OcrTrainingService {
     // Python OCR service after each run. The DB-level RUNNING constraint (V30 partial unique
     // index) prevents concurrent training API calls, but cannot prevent two OCR service replicas
     // from diverging on model state. Deploy as a single instance only. See ADR-001.
-    @Transactional
     public OcrTrainingRun triggerTraining(UUID triggeredBy) {
+        // Short transaction: guard check + create RUNNING row, then commit immediately.
+        // The DB connection is released before the OCR HTTP call, which can take several minutes.
+        OcrTrainingRun run = Objects.requireNonNull(txTemplate.execute(status -> {
             if (trainingRunRepository.findFirstByStatus(TrainingStatus.RUNNING).isPresent()) {
                 throw DomainException.conflict(ErrorCode.TRAINING_ALREADY_RUNNING,
                         "A training run is already in progress");
@@ -64,19 +69,20 @@ public class OcrTrainingService {
                     .distinct()
                     .count();
 
-        OcrTrainingRun run = OcrTrainingRun.builder()
+            OcrTrainingRun newRun = OcrTrainingRun.builder()
                     .status(TrainingStatus.RUNNING)
                     .blockCount(eligibleBlocks.size())
                     .documentCount((int) documentCount)
                     .modelName("german_kurrent")
                     .triggeredBy(triggeredBy)
                     .build();
-        run = trainingRunRepository.save(run);
+            return trainingRunRepository.save(newRun);
+        }));
 
         String runId = run.getId().toString();
         MDC.put("trainingRunId", runId);
         log.info("Started training run {} with {} blocks from {} documents",
-                runId, eligibleBlocks.size(), documentCount);
+                runId, run.getBlockCount(), run.getDocumentCount());
 
         try {
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -86,29 +92,34 @@ public class OcrTrainingService {
             log.info("[trainingRun={}] Sending {} bytes to OCR service", runId, zipBytes.length);
             OcrClient.TrainingResult result = ocrClient.trainModel(zipBytes);
 
+            return Objects.requireNonNull(txTemplate.execute(status -> {
                 run.setStatus(TrainingStatus.DONE);
                 run.setCompletedAt(Instant.now());
                 run.setCer(result.cer());
                 run.setLoss(result.loss());
                 run.setAccuracy(result.accuracy());
                 run.setEpochs(result.epochs());
-            run = trainingRunRepository.save(run);
+                OcrTrainingRun updated = trainingRunRepository.save(run);
                 log.info("[trainingRun={}] Training completed — cer={} epochs={}", runId, result.cer(), result.epochs());
+                return updated;
+            }));
         } catch (Exception e) {
+            return Objects.requireNonNull(txTemplate.execute(status -> {
                 run.setStatus(TrainingStatus.FAILED);
                 run.setErrorMessage(e.getMessage());
                 run.setCompletedAt(Instant.now());
-            run = trainingRunRepository.save(run);
+                OcrTrainingRun failed = trainingRunRepository.save(run);
                 log.error("[trainingRun={}] Training failed: {}", runId, e.getMessage(), e);
+                return failed;
+            }));
         } finally {
             MDC.remove("trainingRunId");
         }
-
-        return run;
     }
 
-    @Transactional
     public OcrTrainingRun triggerSegTraining(UUID triggeredBy) {
+        // Same pattern as triggerTraining: narrow transactions around DB writes only.
+        OcrTrainingRun run = Objects.requireNonNull(txTemplate.execute(status -> {
             if (trainingRunRepository.findFirstByStatus(TrainingStatus.RUNNING).isPresent()) {
                 throw DomainException.conflict(ErrorCode.TRAINING_ALREADY_RUNNING,
                         "A training run is already in progress");
@@ -125,19 +136,20 @@ public class OcrTrainingService {
                     .distinct()
                     .count();
 
-        OcrTrainingRun run = OcrTrainingRun.builder()
+            OcrTrainingRun newRun = OcrTrainingRun.builder()
                     .status(TrainingStatus.RUNNING)
                     .blockCount(segBlocks.size())
                     .documentCount((int) documentCount)
                     .modelName("blla")
                     .triggeredBy(triggeredBy)
                     .build();
-        run = trainingRunRepository.save(run);
+            return trainingRunRepository.save(newRun);
+        }));
 
         String runId = run.getId().toString();
         MDC.put("trainingRunId", runId);
         log.info("Started segmentation training run {} with {} segments from {} documents",
-                runId, segBlocks.size(), documentCount);
+                runId, run.getBlockCount(), run.getDocumentCount());
 
         try {
             ByteArrayOutputStream baos = new ByteArrayOutputStream();
@@ -147,24 +159,28 @@ public class OcrTrainingService {
             log.info("[trainingRun={}] Sending {} bytes to OCR service for segtrain", runId, zipBytes.length);
             OcrClient.TrainingResult result = ocrClient.segtrainModel(zipBytes);
 
+            return Objects.requireNonNull(txTemplate.execute(status -> {
                 run.setStatus(TrainingStatus.DONE);
                 run.setCompletedAt(Instant.now());
                 run.setLoss(result.loss());
                 run.setAccuracy(result.accuracy());
                 run.setEpochs(result.epochs());
-            run = trainingRunRepository.save(run);
+                OcrTrainingRun updated = trainingRunRepository.save(run);
                 log.info("[trainingRun={}] Segmentation training completed — epochs={}", runId, result.epochs());
+                return updated;
+            }));
         } catch (Exception e) {
+            return Objects.requireNonNull(txTemplate.execute(status -> {
                 run.setStatus(TrainingStatus.FAILED);
                 run.setErrorMessage(e.getMessage());
                 run.setCompletedAt(Instant.now());
-            run = trainingRunRepository.save(run);
+                OcrTrainingRun failed = trainingRunRepository.save(run);
                 log.error("[trainingRun={}] Segmentation training failed: {}", runId, e.getMessage(), e);
+                return failed;
+            }));
         } finally {
             MDC.remove("trainingRunId");
         }
-
-        return run;
     }
 
     public TrainingInfoResponse getTrainingInfo() {
@@ -174,7 +190,7 @@ public class OcrTrainingService {
                 .distinct()
                 .count();
 
-        int totalOcrBlocks = blockRepository.findAll().size();
+        int totalOcrBlocks = (int) blockRepository.count();
         int availableSegBlocks = segmentationTrainingExportService.querySegmentationBlocks().size();
 
         List<OcrTrainingRun> recentRuns = trainingRunRepository.findTop5ByOrderByCreatedAtDesc();

backend/src/test/java/org/raddatz/familienarchiv/service/OcrTrainingServiceTest.java

@@ -9,6 +9,8 @@ import org.raddatz.familienarchiv.model.TrainingStatus;
 import org.raddatz.familienarchiv.model.TranscriptionBlock;
 import org.raddatz.familienarchiv.repository.OcrTrainingRunRepository;
 import org.raddatz.familienarchiv.repository.TranscriptionBlockRepository;
+import org.springframework.transaction.support.TransactionCallback;
+import org.springframework.transaction.support.TransactionTemplate;
 
 import java.time.Instant;
 import java.util.List;
@@ -29,6 +31,7 @@ class OcrTrainingServiceTest {
     OcrClient ocrClient;
     OcrHealthClient healthClient;
     TranscriptionBlockRepository blockRepository;
+    TransactionTemplate txTemplate;
     OcrTrainingService service;
 
     @BeforeEach
@@ -39,10 +42,17 @@ class OcrTrainingServiceTest {
         ocrClient = mock(OcrClient.class);
         healthClient = mock(OcrHealthClient.class);
         blockRepository = mock(TranscriptionBlockRepository.class);
+        txTemplate = mock(TransactionTemplate.class);
 
-        service = new OcrTrainingService(runRepository, exportService, segExportService, ocrClient, healthClient, blockRepository);
+        // Execute transaction callbacks inline so unit tests run without a real DataSource
+        when(txTemplate.execute(any())).thenAnswer(inv -> {
+            TransactionCallback<?> callback = inv.getArgument(0);
+            return callback.doInTransaction(null);
+        });
 
-        when(blockRepository.findAll()).thenReturn(List.of());
+        service = new OcrTrainingService(runRepository, exportService, segExportService, ocrClient, healthClient, blockRepository, txTemplate);
+
+        when(blockRepository.count()).thenReturn(0L);
         when(runRepository.findTop5ByOrderByCreatedAtDesc()).thenReturn(List.of());
         when(segExportService.querySegmentationBlocks()).thenReturn(List.of());
     }