fix(indexing): Memory management improvements

src/main/java/org/folio/search/service/InstanceChildrenResourceService.java

@@ -93,6 +93,16 @@ public void persistChildrenOnReindex(String tenantId, ResourceType resourceType,
         .tenant(tenantId)
         ._new(instance))
       .toList();
-    persistChildren(tenantId, resourceType, events);
+
+    var extractors = resourceExtractors.get(resourceType);
+    if (extractors == null) {
+      return;
+    }
+
+    var shared = consortiumTenantProvider.isCentralTenant(tenantId);
+
+    // Process child resources normally
+    extractors.forEach(resourceExtractor ->
+      resourceExtractor.persistChildren(tenantId, shared, events));
   }
 }

src/main/java/org/folio/search/service/converter/MultiTenantSearchDocumentConverter.java

@@ -57,6 +57,29 @@ public Map<String, List<SearchDocumentBody>> convert(Collection<ResourceEvent> r
       .collect(groupingBy(SearchDocumentBody::getResource));
   }
 
+  /**
+   * Converts {@link ResourceEvent} objects to a flat list of {@link SearchDocumentBody} objects.
+   * All events are expected to carry the same tenant ID that matches the current execution context —
+   * per-tenant grouping and context switching are therefore skipped entirely.
+   *
+   * @param resourceEvents list with {@link ResourceEvent} objects, all belonging to the current tenant
+   * @return flat {@link List} of {@link SearchDocumentBody} objects
+   */
+  public List<SearchDocumentBody> convertForReindex(Collection<ResourceEvent> resourceEvents) {
+    log.debug("convertForReindex:: by [resourceEvents.size: {}]", collectionToLogMsg(resourceEvents, true));
+
+    if (CollectionUtils.isEmpty(resourceEvents)) {
+      return List.of();
+    }
+
+    return resourceEvents.stream()
+      .flatMap(this::populateResourceEvents)
+      .map(event -> event.getId() != null ? event : event.id(getResourceEventId(event)))
+      .map(searchDocumentConverter::convert)
+      .flatMap(Optional::stream)
+      .toList();
+  }
+
   private List<SearchDocumentBody> convertForTenant(Entry<String, List<ResourceEvent>> entry) {
     var convert = (Supplier<List<SearchDocumentBody>>) () ->
       entry.getValue().stream()

src/main/java/org/folio/search/service/converter/SearchDocumentConverter.java

@@ -82,8 +82,11 @@ private SearchDocumentBody convert(ConversionContext context) {
     var baseFields = convertMapUsingResourceFields(getNewAsMap(resourceEvent), resourceDescriptionFields, context);
     var searchFields = searchFieldsProcessor.getSearchFields(context);
     var resultDocument = mergeSafely(baseFields, searchFields);
-    return SearchDocumentBody.of(searchDocumentBodyConverter.apply(resultDocument),
-      indexingDataFormat, resourceEvent, INDEX);
+    // Release the large _new Map before serialization — resultDocument is already a fully independent copy.
+    // ResourceEvent is still referenced by SearchDocumentBody for id/tenant/resource metadata only.
+    resourceEvent.setNew(null);
+    var documentBody = searchDocumentBodyConverter.apply(resultDocument);
+    return SearchDocumentBody.of(documentBody, indexingDataFormat, resourceEvent, INDEX);
   }
 
   private List<String> getResourceLanguages(List<String> languageSource, Map<String, Object> resourceData) {

src/main/java/org/folio/search/service/converter/preprocessor/extractor/impl/CallNumberResourceExtractor.java

@@ -2,26 +2,24 @@
 
 import static org.apache.commons.collections4.MapUtils.getMap;
 import static org.apache.commons.collections4.MapUtils.getString;
-import static org.folio.search.model.entity.CallNumberEntity.CALL_NUMBER_MAX_LENGTH;
+import static org.apache.commons.lang3.StringUtils.truncate;
 import static org.folio.search.utils.SearchConverterUtils.getNewAsMap;
 import static org.folio.search.utils.SearchUtils.prepareForExpectedFormat;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 import java.util.Set;
 import lombok.extern.log4j.Log4j2;
 import org.apache.commons.lang3.StringUtils;
 import org.folio.search.domain.dto.ResourceEvent;
 import org.folio.search.domain.dto.TenantConfiguredFeature;
-import org.folio.search.model.entity.CallNumberEntity;
-import org.folio.search.model.entity.InstanceCallNumberEntity;
 import org.folio.search.model.types.ResourceType;
 import org.folio.search.service.FeatureConfigService;
 import org.folio.search.service.converter.preprocessor.extractor.ChildResourceExtractor;
 import org.folio.search.service.reindex.jdbc.CallNumberRepository;
-import org.folio.search.utils.JsonConverter;
+import org.folio.search.utils.ShaUtils;
 import org.springframework.context.annotation.Lazy;
 import org.springframework.stereotype.Component;
 
@@ -36,14 +34,16 @@ public class CallNumberResourceExtractor extends ChildResourceExtractor {
   public static final String SUFFIX_FIELD = "suffix";
   public static final String TYPE_ID_FIELD = "typeId";
 
-  private final JsonConverter jsonConverter;
+  private static final int CALL_NUMBER_MAX_LENGTH = 50;
+  private static final int CALL_NUMBER_PREFIX_MAX_LENGTH = 20;
+  private static final int CALL_NUMBER_SUFFIX_MAX_LENGTH = 25;
+  private static final int CALL_NUMBER_TYPE_MAX_LENGTH = 40;
+
   private final FeatureConfigService featureConfigService;
 
   public CallNumberResourceExtractor(CallNumberRepository repository,
-                                     JsonConverter jsonConverter,
                                      FeatureConfigService featureConfigService) {
     super(repository);
-    this.jsonConverter = jsonConverter;
     this.featureConfigService = featureConfigService;
   }
 
@@ -57,14 +57,12 @@ protected List<Map<String, Object>> constructRelations(boolean shared, ResourceE
                                                          List<Map<String, Object>> entities) {
     var resourceMap = getNewAsMap(event);
     return entities.stream()
-      .map(entity -> InstanceCallNumberEntity.builder()
-        .callNumberId(getString(entity, "id"))
-        .itemId(getString(resourceMap, "id"))
-        .instanceId(getString(resourceMap, "instanceId"))
-        .locationId(getString(resourceMap, "effectiveLocationId"))
-        .tenantId(event.getTenant())
-        .build())
-      .map(jsonConverter::convertToMap)
+      .map(entity -> Map.<String, Object>of(
+        "callNumberId", getString(entity, "id"),
+        "itemId", getString(resourceMap, "id"),
+        "instanceId", getString(resourceMap, "instanceId"),
+        "locationId", getString(resourceMap, "effectiveLocationId"),
+        "tenantId", event.getTenant()))
       .toList();
   }
 
@@ -73,9 +71,24 @@ protected Map<String, Object> constructEntity(Map<String, Object> entityProperti
     if (entityProperties == null || !featureConfigService.isEnabled(TenantConfiguredFeature.BROWSE_CALL_NUMBERS)) {
       return Collections.emptyMap();
     }
-    return toCallNumberEntity(entityProperties)
-      .map(jsonConverter::convertToMap)
-      .orElse(Collections.emptyMap());
+    var callNumberComponents = getCallNumberComponents(entityProperties);
+    var callNumber = prepareForExpectedFormat(
+      getString(callNumberComponents, CALL_NUMBER_FIELD), CALL_NUMBER_MAX_LENGTH);
+    if (StringUtils.isBlank(callNumber)) {
+      return Collections.emptyMap();
+    }
+    var callNumberPrefix = truncate(getString(callNumberComponents, PREFIX_FIELD), CALL_NUMBER_PREFIX_MAX_LENGTH);
+    var callNumberSuffix = truncate(getString(callNumberComponents, SUFFIX_FIELD), CALL_NUMBER_SUFFIX_MAX_LENGTH);
+    var callNumberTypeId = truncate(getString(callNumberComponents, TYPE_ID_FIELD), CALL_NUMBER_TYPE_MAX_LENGTH);
+    var id = ShaUtils.sha(callNumber, callNumberPrefix, callNumberSuffix, callNumberTypeId);
+
+    var entity = new HashMap<String, Object>();
+    entity.put("id", id);
+    entity.put("callNumber", callNumber);
+    entity.put("callNumberPrefix", callNumberPrefix);
+    entity.put("callNumberSuffix", callNumberSuffix);
+    entity.put("callNumberTypeId", callNumberTypeId);
+    return entity;
   }
 
   @Override
@@ -88,22 +101,6 @@ protected Set<Map<String, Object>> getChildResources(Map<String, Object> event)
     return Set.of(event);
   }
 
-  private Optional<CallNumberEntity> toCallNumberEntity(Map<String, Object> entityProperties) {
-    var callNumberComponents = getCallNumberComponents(entityProperties);
-    var callNumber = prepareForExpectedFormat(getString(callNumberComponents, CALL_NUMBER_FIELD),
-      CALL_NUMBER_MAX_LENGTH);
-    if (StringUtils.isNotBlank(callNumber)) {
-      var callNumberEntity = CallNumberEntity.builder()
-        .callNumber(callNumber)
-        .callNumberPrefix(getString(callNumberComponents, PREFIX_FIELD))
-        .callNumberSuffix(getString(callNumberComponents, SUFFIX_FIELD))
-        .callNumberTypeId(getString(callNumberComponents, TYPE_ID_FIELD))
-        .build();
-      return Optional.of(callNumberEntity);
-    }
-    return Optional.empty();
-  }
-
   @SuppressWarnings("unchecked")
   private Map<String, Object> getCallNumberComponents(Map<String, Object> entityProperties) {
     return (Map<String, Object>) getMap(entityProperties, EFFECTIVE_CALL_NUMBER_COMPONENTS_FIELD,

src/main/java/org/folio/search/service/reindex/ReindexOrchestrationService.java

@@ -1,6 +1,5 @@
 package org.folio.search.service.reindex;
 
-import java.util.Collection;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.log4j.Log4j2;
 import org.apache.logging.log4j.message.FormattedMessage;
@@ -75,7 +74,7 @@ public boolean process(ReindexRecordsEvent event) {
   private FolioIndexOperationResponse fetchRecordsAndIndexForUploadRange(ReindexRangeIndexEvent event) {
     try {
       var resourceEvents = uploadRangeService.fetchRecordRange(event);
-      var documents = documentConverter.convert(resourceEvents).values().stream().flatMap(Collection::stream).toList();
+      var documents = documentConverter.convertForReindex(resourceEvents);
       return elasticRepository.indexResources(documents);
     } catch (Exception ex) {
       throw handleReindexUploadFailure(event, ex.getMessage());

src/main/java/org/folio/search/service/reindex/jdbc/CallNumberRepository.java

@@ -258,10 +258,6 @@ protected RowMapper<Map<String, Object>> rowToMapMapper() {
   protected RowMapper<Map<String, Object>> rowToMapMapper2() {
     return (rs, rowNum) -> {
       var callNumberMap = getCallNumberMap(rs);
-      var maps = jsonConverter.fromJsonToListOfMaps(getInstances(rs)).stream().filter(Objects::nonNull).toList();
-      if (!maps.isEmpty()) {
-        callNumberMap.put(SUB_RESOURCE_INSTANCES_FIELD, maps);
-      }
       callNumberMap.put(LAST_UPDATED_DATE_FIELD, rs.getTimestamp("last_updated_date"));
       return callNumberMap;
     };
@@ -278,8 +274,7 @@ private Map<String, Object> getCallNumberMap(ResultSet rs) throws SQLException {
     callNumberMap.put(CALL_NUMBER_PREFIX_FIELD, getCallNumberPrefix(rs));
     callNumberMap.put(CALL_NUMBER_SUFFIX_FIELD, callNumberSuffix);
     callNumberMap.put(CALL_NUMBER_TYPE_ID_FIELD, getCallNumberTypeId(rs));
-    var subResources = jsonConverter.toJson(parseInstanceSubResources(getInstances(rs)));
-    var maps = jsonConverter.fromJsonToListOfMaps(subResources).stream().filter(Objects::nonNull).toList();
+    var maps = jsonConverter.fromJsonToListOfMaps(getInstances(rs)).stream().filter(Objects::nonNull).toList();
     if (!maps.isEmpty()) {
       callNumberMap.put(SUB_RESOURCE_INSTANCES_FIELD, maps);
     }

src/main/java/org/folio/search/service/reindex/jdbc/ClassificationRepository.java

@@ -179,19 +179,7 @@ protected String getFetchBySql() {
 
   @Override
   protected RowMapper<Map<String, Object>> rowToMapMapper() {
-    return (rs, rowNum) -> {
-      Map<String, Object> classification = new HashMap<>();
-      classification.put("id", getId(rs));
-      classification.put(CLASSIFICATION_NUMBER_ENTITY_FIELD, getNumber(rs));
-      classification.put("typeId", getTypeId(rs));
-
-      var maps = jsonConverter.fromJsonToListOfMaps(getInstances(rs)).stream().filter(Objects::nonNull).toList();
-      if (!maps.isEmpty()) {
-        classification.put(SUB_RESOURCE_INSTANCES_FIELD, maps);
-      }
-
-      return classification;
-    };
+    return (rs, rowNum) -> buildClassificationMap(rs);
   }
 
   @Override
@@ -238,21 +226,26 @@ public void saveAll(ChildResourceEntityBatch entityBatch) {
 
   protected RowMapper<Map<String, Object>> rowToMapMapper2() {
     return (rs, rowNum) -> {
-      Map<String, Object> classification = new HashMap<>();
-      classification.put("id", getId(rs));
-      classification.put(CLASSIFICATION_NUMBER_ENTITY_FIELD, getNumber(rs));
-      classification.put("typeId", getTypeId(rs));
+      var classification = buildClassificationMap(rs);
       classification.put(LAST_UPDATED_DATE_FIELD, rs.getTimestamp("last_updated_date"));
-
-      var maps = jsonConverter.fromJsonToListOfMaps(getInstances(rs)).stream().filter(Objects::nonNull).toList();
-      if (!maps.isEmpty()) {
-        classification.put(SUB_RESOURCE_INSTANCES_FIELD, maps);
-      }
-
       return classification;
     };
   }
 
+  private Map<String, Object> buildClassificationMap(ResultSet rs) throws SQLException {
+    Map<String, Object> classification = new HashMap<>();
+    classification.put("id", getId(rs));
+    classification.put(CLASSIFICATION_NUMBER_ENTITY_FIELD, getNumber(rs));
+    classification.put("typeId", getTypeId(rs));
+
+    var maps = jsonConverter.fromJsonToListOfMaps(getInstances(rs)).stream().filter(Objects::nonNull).toList();
+    if (!maps.isEmpty()) {
+      classification.put(SUB_RESOURCE_INSTANCES_FIELD, maps);
+    }
+
+    return classification;
+  }
+
   private String getId(ResultSet rs) throws SQLException {
     return rs.getString("id");
   }