Merge branch 'codex/cw-7519-intercom-stalled-retry-15m' into codex/cw-7615-intercom-bulk-message-writes

## Description

Reduces sustained load during large Intercom imports by limiting
conversation list pages to 10 while retaining 50-contact pages. Cursor
and provider total-count behavior remain unchanged.

The one-minute progress heartbeat now lives in parent PR #15050 because
stalled-import detection must be safe when that PR is deployed
independently. This child PR therefore contains only the smaller-page
delta.

This is Phase 1, Task 2 of the [Intercom import optimization plan
(CW-7615)](https://linear.app/chatwoot/issue/CW-7615/optimize-intercom-import-reliability-and-bulk-message-ingestion).

This PR is stacked on #15050 and should be reviewed as the two-file
delta from `codex/cw-7519-intercom-stalled-retry-15m`.

## Closes

-
[CW-7615](https://linear.app/chatwoot/issue/CW-7615/optimize-intercom-import-reliability-and-bulk-message-ingestion)

## Type of change

- [x] Bug fix (non-breaking change which fixes an issue)

## How to test

1. Start an Intercom import containing contacts and conversations across
multiple source pages.
2. Confirm contact list requests retain a page size of 50.
3. Confirm conversation list requests use a page size of 10.
4. Confirm page cursors and displayed provider totals continue advancing
normally.
5. Confirm the parent PR heartbeat keeps long conversations fresh while
these shorter pages are processed.

## Checklist

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have added tests that prove the change is effective
- [x] New and existing focused tests pass locally with my changes

app/controllers/api/v1/accounts/data_imports_controller.rb

@@ -4,7 +4,7 @@ class Api::V1::Accounts::DataImportsController < Api::V1::Accounts::BaseControll
   DATA_IMPORT_FEATURE = 'data_import'.freeze
 
   before_action :ensure_data_import_feature_enabled
-  before_action :set_data_import, only: [:show, :start, :abandon, :error_logs, :skip_logs]
+  before_action :set_data_import, only: [:show, :start, :retry_import, :abandon, :error_logs, :skip_logs]
   before_action :check_authorization
 
   def index
@@ -59,6 +59,24 @@ class Api::V1::Accounts::DataImportsController < Api::V1::Accounts::BaseControll
     render_show
   end
 
+  def retry_import
+    retry_service = DataImports::Intercom::RetryService.new(account: Current.account, data_import: @data_import)
+    retry_result = retry_service.perform
+    @data_import = retry_service.data_import
+
+    case retry_result
+    when :enqueue
+      DataImports::Intercom::ImportJob.perform_later(@data_import, @data_import.active_intercom_import_run_id)
+      render_show
+    when :not_stalled
+      render json: { message: 'This Intercom import is no longer stalled.' }, status: :unprocessable_entity
+    when :active_import_exists
+      render json: { message: 'Another Intercom import is already in progress.' }, status: :unprocessable_entity
+    when :access_token_missing
+      render json: { message: 'The Intercom access key for this import is unavailable.' }, status: :unprocessable_entity
+    end
+  end
+
   def abandon
     @data_import.abandon!
     render_show

app/javascript/dashboard/api/dataImports.js

@@ -11,6 +11,10 @@ class DataImportsAPI extends ApiClient {
     return axios.post(`${this.url}/${id}/start`);
   }
 
+  retry(id) {
+    return axios.post(`${this.url}/${id}/retry`);
+  }
+
   abandon(id) {
     return axios.post(`${this.url}/${id}/abandon`);
   }

app/javascript/dashboard/i18n/locale/en/settings.json

@@ -462,6 +462,7 @@
       "STATUS": "Status",
       "IMPORTED": "Imported",
       "CREATED": "Created",
+      "RETRY": "Retry",
       "ABANDON": "Abandon"
     },
     "DETAIL": {
@@ -508,6 +509,8 @@
     },
     "ALERTS": {
       "IMPORT_STARTED": "Intercom import has started.",
+      "IMPORT_RETRIED": "Intercom import has been queued to resume.",
+      "IMPORT_RETRY_FAILED": "Could not retry the Intercom import.",
       "IMPORT_ABANDONED": "Intercom import has been abandoned.",
       "IMPORT_FAILED": "Could not start the Intercom import."
     }

app/javascript/dashboard/routes/dashboard/settings/data/Show.vue

@@ -26,6 +26,7 @@ const dataImport = ref(null);
 const isLoading = ref(true);
 const isRefreshing = ref(false);
 const isPolling = ref(false);
+const isRetrying = ref(false);
 const isAbandoning = ref(false);
 const isDownloadingErrorLogs = ref(false);
 const isDownloadingSkipLogs = ref(false);
@@ -35,6 +36,7 @@ const errorsOpen = ref(true);
 const skipLogsOpen = ref(true);
 let pollTimer;
 let isPageActive = false;
+let importRequestVersion = 0;
 
 const hasActiveImport = computed(() => isActiveImport(dataImport.value));
 
@@ -50,6 +52,7 @@ const fetchImport = async ({
   manual = false,
   requestedSkipLogsType = selectedSkipLogsType.value,
 } = {}) => {
+  const requestVersion = importRequestVersion;
   if (showLoader) {
     isLoading.value = true;
   } else if (manual) {
@@ -60,6 +63,8 @@ const fetchImport = async ({
     const response = await DataImportsAPI.show(route.params.dataImportId, {
       skip_logs_type: requestedSkipLogsType || undefined,
     });
+    if (requestVersion !== importRequestVersion) return;
+
     dataImport.value = response.data;
     selectedSkipLogsType.value =
       response.data.skip_logs_filters?.selected_source_object_type ||
@@ -105,6 +110,13 @@ const refreshImportInBackground = async () => {
   }
 };
 
+const startPolling = () => {
+  stopPolling();
+  if (!isPageActive || !hasActiveImport.value) return;
+
+  pollTimer = window.setInterval(refreshImportInBackground, POLL_INTERVAL_MS);
+};
+
 const abandonImport = async () => {
   isAbandoning.value = true;
   try {
@@ -117,6 +129,22 @@ const abandonImport = async () => {
   }
 };
 
+const retryImport = async () => {
+  isRetrying.value = true;
+  importRequestVersion += 1;
+  stopPolling();
+  try {
+    const response = await DataImportsAPI.retry(dataImport.value.id);
+    dataImport.value = response.data;
+    useAlert(t('DATA_IMPORTS.ALERTS.IMPORT_RETRIED'));
+  } catch {
+    useAlert(t('DATA_IMPORTS.ALERTS.IMPORT_RETRY_FAILED'));
+  } finally {
+    isRetrying.value = false;
+    if (hasActiveImport.value) startPolling();
+  }
+};
+
 const downloadCsv = (response, filename) => {
   const url = window.URL.createObjectURL(
     new Blob([response.data], { type: 'text/csv' })
@@ -150,13 +178,6 @@ const downloadSkipLogs = async () => {
   }
 };
 
-const startPolling = () => {
-  stopPolling();
-  if (!isPageActive || !hasActiveImport.value) return;
-
-  pollTimer = window.setInterval(refreshImportInBackground, POLL_INTERVAL_MS);
-};
-
 const handleVisibilityChange = () => {
   if (isPageActive && !document.hidden && hasActiveImport.value) {
     refreshImportInBackground();
@@ -197,9 +218,11 @@ onBeforeUnmount(() => {
       <ImportDetailHeader
         :data-import="dataImport"
         :is-refreshing="isRefreshing"
+        :is-retrying="isRetrying"
         :is-abandoning="isAbandoning"
         :is-polling="isPolling"
         @refresh="fetchImport({ manual: true })"
+        @retry="retryImport"
         @abandon="abandonImport"
       />
     </template>

app/javascript/dashboard/routes/dashboard/settings/data/components/ImportDetailHeader.vue

@@ -21,6 +21,10 @@ const props = defineProps({
     type: Boolean,
     default: false,
   },
+  isRetrying: {
+    type: Boolean,
+    default: false,
+  },
   isAbandoning: {
     type: Boolean,
     default: false,
@@ -31,7 +35,7 @@ const props = defineProps({
   },
 });
 
-defineEmits(['refresh', 'abandon']);
+defineEmits(['refresh', 'retry', 'abandon']);
 
 const { t } = useI18n();
 
@@ -90,11 +94,23 @@ const canAbandonImport = computed(() => isAbandonableImport(props.dataImport));
             :title="$t('DATA_IMPORTS.MONITOR.REFRESH')"
             @click="$emit('refresh')"
           />
+          <Button
+            v-if="dataImport?.stalled"
+            outline
+            slate
+            size="sm"
+            icon="i-lucide-rotate-ccw"
+            :is-loading="isRetrying"
+            :disabled="isAbandoning"
+            :label="$t('DATA_IMPORTS.TABLE.RETRY')"
+            @click="$emit('retry')"
+          />
           <Button
             v-if="canAbandonImport"
             ruby
             size="sm"
             :is-loading="isAbandoning"
+            :disabled="isRetrying"
             :label="$t('DATA_IMPORTS.TABLE.ABANDON')"
             @click="$emit('abandon')"
           />

app/javascript/dashboard/routes/dashboard/settings/data/specs/ImportDetailHeader.spec.js

@@ -0,0 +1,85 @@
+import { mount } from '@vue/test-utils';
+import ImportDetailHeader from '../components/ImportDetailHeader.vue';
+
+vi.mock('vue-i18n', () => ({
+  useI18n: () => ({ t: key => key }),
+}));
+
+const ButtonStub = {
+  name: 'Button',
+  props: {
+    label: { type: String, default: '' },
+    icon: { type: String, default: '' },
+    isLoading: { type: Boolean, default: false },
+  },
+  emits: ['click'],
+  template: `
+    <button
+      :data-label="label"
+      :data-icon="icon"
+      :data-loading="isLoading"
+      @click="$emit('click')"
+    >
+      {{ label }}
+    </button>
+  `,
+};
+
+const BaseSettingsHeaderStub = {
+  template: `
+    <section>
+      <slot name="title" />
+      <slot name="description" />
+    </section>
+  `,
+};
+
+const mountHeader = props =>
+  mount(ImportDetailHeader, {
+    props,
+    global: {
+      stubs: {
+        Button: ButtonStub,
+        BaseSettingsHeader: BaseSettingsHeaderStub,
+      },
+      mocks: {
+        $t: key => key,
+      },
+    },
+  });
+
+describe('ImportDetailHeader', () => {
+  const activeImport = {
+    id: 1,
+    name: 'Intercom import',
+    data_type: 'intercom',
+    source_provider: 'intercom',
+    status: 'processing',
+    stalled: true,
+  };
+
+  it('shows Retry between Refresh and Abandon for stalled imports', async () => {
+    const wrapper = mountHeader({ dataImport: activeImport });
+    const buttons = wrapper.findAll('button');
+
+    expect(buttons.map(button => button.attributes('data-label'))).toEqual([
+      '',
+      'DATA_IMPORTS.TABLE.RETRY',
+      'DATA_IMPORTS.TABLE.ABANDON',
+    ]);
+
+    await buttons[1].trigger('click');
+
+    expect(wrapper.emitted('retry')).toHaveLength(1);
+  });
+
+  it('hides Retry when the server does not report the import as stalled', () => {
+    const wrapper = mountHeader({
+      dataImport: { ...activeImport, stalled: false },
+    });
+
+    expect(
+      wrapper.find('[data-label="DATA_IMPORTS.TABLE.RETRY"]').exists()
+    ).toBe(false);
+  });
+});

app/javascript/dashboard/routes/dashboard/settings/data/specs/showActions.spec.js

@@ -0,0 +1,161 @@
+import { flushPromises, mount } from '@vue/test-utils';
+import { KeepAlive, defineComponent, h, nextTick } from 'vue';
+import { useAlert } from 'dashboard/composables';
+import DataImportsAPI from 'dashboard/api/dataImports';
+import Show from '../Show.vue';
+import { POLL_INTERVAL_MS } from '../importStatus';
+
+vi.mock('dashboard/api/dataImports', () => ({
+  default: {
+    show: vi.fn(),
+    retry: vi.fn(),
+  },
+}));
+
+vi.mock('dashboard/composables', () => ({
+  useAlert: vi.fn(),
+}));
+
+vi.mock('vue-i18n', () => ({
+  useI18n: () => ({ t: key => key }),
+}));
+
+vi.mock('vue-router', async importOriginal => ({
+  ...(await importOriginal()),
+  useRoute: () => ({ params: { dataImportId: 1 } }),
+}));
+
+const SettingsLayoutStub = {
+  template: `
+    <main>
+      <slot name="header" />
+      <slot name="body" />
+    </main>
+  `,
+};
+
+const ImportDetailHeaderStub = {
+  name: 'ImportDetailHeader',
+  props: {
+    dataImport: {
+      type: Object,
+      default: null,
+    },
+  },
+  emits: ['retry'],
+  template: `
+    <button
+      v-if="dataImport?.stalled"
+      data-test="retry"
+      @click="$emit('retry')"
+    />
+  `,
+};
+
+const deferredRequest = () => {
+  let resolve;
+  const promise = new Promise(resolvePromise => {
+    resolve = resolvePromise;
+  });
+  return { promise, resolve };
+};
+
+const mountShow = () => {
+  const Host = defineComponent({
+    render() {
+      return h(KeepAlive, null, { default: () => h(Show) });
+    },
+  });
+
+  return mount(Host, {
+    global: {
+      stubs: {
+        SettingsLayout: SettingsLayoutStub,
+        ImportDetailHeader: ImportDetailHeaderStub,
+        ImportSummaryTiles: true,
+        ImportProgress: true,
+        ImportErrorsSection: true,
+        ImportSkipLogsSection: true,
+      },
+      mocks: {
+        $t: key => key,
+      },
+    },
+  });
+};
+
+describe('data import detail actions', () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    DataImportsAPI.show.mockResolvedValue({
+      data: {
+        id: 1,
+        status: 'processing',
+        stalled: true,
+        skip_logs_filters: {},
+      },
+    });
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+    vi.clearAllMocks();
+  });
+
+  it('retries a stalled import and replaces the page state', async () => {
+    DataImportsAPI.retry.mockResolvedValue({
+      data: {
+        id: 1,
+        status: 'pending',
+        stalled: false,
+        skip_logs_filters: {},
+      },
+    });
+    const wrapper = mountShow();
+    await nextTick();
+    await flushPromises();
+
+    await wrapper.find('[data-test="retry"]').trigger('click');
+    await flushPromises();
+
+    expect(DataImportsAPI.retry).toHaveBeenCalledWith(1);
+    expect(useAlert).toHaveBeenCalledWith('DATA_IMPORTS.ALERTS.IMPORT_RETRIED');
+    wrapper.unmount();
+  });
+
+  it('ignores an older poll response after retry succeeds', async () => {
+    const pollRequest = deferredRequest();
+    DataImportsAPI.retry.mockResolvedValue({
+      data: {
+        id: 1,
+        status: 'pending',
+        stalled: false,
+        skip_logs_filters: {},
+      },
+    });
+    const wrapper = mountShow();
+    await nextTick();
+    await flushPromises();
+
+    DataImportsAPI.show.mockReturnValueOnce(pollRequest.promise);
+    await vi.advanceTimersByTimeAsync(POLL_INTERVAL_MS);
+    expect(DataImportsAPI.show).toHaveBeenCalledTimes(2);
+
+    await wrapper.find('[data-test="retry"]').trigger('click');
+    await flushPromises();
+    expect(wrapper.find('[data-test="retry"]').exists()).toBe(false);
+
+    pollRequest.resolve({
+      data: {
+        id: 1,
+        status: 'processing',
+        stalled: true,
+        skip_logs_filters: {},
+      },
+    });
+    await flushPromises();
+
+    expect(wrapper.find('[data-test="retry"]').exists()).toBe(false);
+    wrapper.unmount();
+  });
+});

app/models/data_import.rb

@@ -33,6 +33,7 @@
 #
 class DataImport < ApplicationRecord
   ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY = 'active_intercom_import_run_id'.freeze
+  INTERCOM_STALLED_AFTER = 15.minutes
   LEGACY_DATA_TYPES = ['contacts'].freeze
   INTEGRATION_DATA_TYPES = ['intercom'].freeze
   IMPORT_TYPES = %w[contacts conversations].freeze
@@ -71,6 +72,10 @@ class DataImport < ApplicationRecord
     failed? || abandoned?
   end
 
+  def stalled?
+    intercom_import? && (pending? || processing?) && updated_at <= INTERCOM_STALLED_AFTER.ago
+  end
+
   def abandonable?
     intercom_import? && (pending? || processing?)
   end

app/policies/data_import_policy.rb

@@ -19,6 +19,10 @@ class DataImportPolicy < ApplicationPolicy
     show?
   end
 
+  def retry_import?
+    show?
+  end
+
   def abandon?
     show?
   end

app/services/data_imports/intercom/importer.rb

@@ -1,5 +1,7 @@
 # rubocop:disable Metrics/ClassLength, Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity, Metrics/MethodLength, Rails/SkipsModelValidations
 class DataImports::Intercom::Importer
+  class InvalidMessagePayloadError < StandardError; end
+
   PageResult = Struct.new(:next_cursor, keyword_init: true) do
     def done?
       next_cursor.blank?
@@ -7,13 +9,29 @@ class DataImports::Intercom::Importer
   end
 
   DEFAULT_IMPORT_TYPES = %w[contacts conversations].freeze
+  CONTACTS_PER_PAGE = 50
+  CONVERSATIONS_PER_PAGE = 10
+  MESSAGES_PER_BATCH = 100
+  HEARTBEAT_INTERVAL = 1.minute
+  QUERY_TIMEOUT_RETRY_LIMIT = 1
+  QUERY_TIMEOUT_RETRY_DELAY_RANGE = (0.2..0.5)
   PROVIDER = 'intercom'.freeze
   ALREADY_IMPORTED_ERROR_CODE = 'DataImports::Intercom::AlreadyImported'.freeze
   SKIPPED_MESSAGE_ERROR_CODE = 'DataImports::Intercom::SkippedMessage'.freeze
   TRUNCATED_PARTS_ERROR_CODE = 'DataImports::Intercom::TruncatedConversationParts'.freeze
+  MESSAGE_MAPPING_UNIQUE_INDEX = :idx_data_import_mappings_on_account_and_source
   E164_REGEX = /\A\+[1-9]\d{1,14}\z/
   INTERCOM_NUMBER_REGEX = /\A[1-9]\d{1,14}\z/
-  REGULAR_MESSAGE_PART_TYPES = %w[comment note source].freeze
+
+  MessageBatchResult = Struct.new(
+    :imported_entries,
+    :skipped_entries,
+    :current_entries,
+    :previous_entries,
+    :messages,
+    :failed_entries,
+    keyword_init: true
+  )
 
   def initialize(data_import:, run_id: nil)
     @data_import = data_import
@@ -22,6 +40,7 @@ class DataImports::Intercom::Importer
     @client = DataImports::Intercom::Client.new(access_token: data_import.access_token)
     @placeholder_inboxes = DataImports::Intercom::PlaceholderInboxBuilder.new(account: @account)
     @stats = default_stats.deep_merge(data_import.stats || {})
+    @dirty_stat_groups = {}
   end
 
   def perform
@@ -44,8 +63,9 @@ class DataImports::Intercom::Importer
   def finish!
     return if @data_import.reload.abandoned?
 
-    has_failures = @data_import.import_errors.non_skip_logs.exists? || @data_import.import_errors.failed.exists?
-    status = has_failures ? :completed_with_errors : :completed
+    error_count = @data_import.import_errors.non_skip_logs.count + @data_import.import_errors.failed.count
+    @stats['errors']['count'] = error_count
+    status = error_count.positive? ? :completed_with_errors : :completed
     @data_import.update!(
       status: status,
       completed_at: Time.current,
@@ -56,14 +76,16 @@ class DataImports::Intercom::Importer
   end
 
   def fail!(error)
-    return if @data_import.reload.abandoned?
+    @data_import.with_lock do
+      next if @data_import.abandoned? || stale_import_run?
 
-    record_run_error(error)
-    @data_import.update!(status: :failed, last_error_at: Time.current)
+      record_run_error(error)
+      @data_import.update!(status: :failed, last_error_at: Time.current)
+    end
   end
 
   def import_contacts_page(starting_after: cursor_for('contacts'))
-    response = @client.list_contacts(starting_after: starting_after)
+    response = @client.list_contacts(starting_after: starting_after, per_page: CONTACTS_PER_PAGE)
     update_stat_total('contacts', response['total_count']) if response['total_count'].present?
     Array(response['data'] || response['contacts']).each do |contact|
       break if import_stopped?
@@ -72,13 +94,14 @@ class DataImports::Intercom::Importer
     end
     return PageResult.new(next_cursor: nil) if import_stopped?
 
+    reconcile_dirty_stats
     next_cursor = response.dig('pages', 'next', 'starting_after')
     update_cursor('contacts', next_cursor)
     PageResult.new(next_cursor: next_cursor)
   end
 
   def import_conversations_page(starting_after: cursor_for('conversations'))
-    response = @client.list_conversations(starting_after: starting_after)
+    response = @client.list_conversations(starting_after: starting_after, per_page: CONVERSATIONS_PER_PAGE)
     update_stat_total('conversations', response['total_count']) if response['total_count'].present?
     Array(response['data'] || response['conversations']).each do |conversation_summary|
       break if import_stopped?
@@ -87,6 +110,7 @@ class DataImports::Intercom::Importer
     end
     return PageResult.new(next_cursor: nil) if import_stopped?
 
+    reconcile_dirty_stats
     next_cursor = response.dig('pages', 'next', 'starting_after')
     update_cursor('conversations', next_cursor)
     PageResult.new(next_cursor: next_cursor)
@@ -153,8 +177,9 @@ class DataImports::Intercom::Importer
     mapped_conversation = mapping&.chatwoot_record
     if mapped_conversation && mapping.data_import_id != @data_import.id
       skip_already_imported_item(item, mapping, already_handled: already_handled)
-      import_source_message(conversation, mapped_conversation, contact)
-      import_conversation_parts(conversation, mapped_conversation, contact)
+      reconcile_item_stats('conversation') if already_handled
+      return unless import_conversation_messages(conversation, mapped_conversation, contact)
+
       update_conversation_activity(mapped_conversation)
       return
     end
@@ -164,17 +189,21 @@ class DataImports::Intercom::Importer
       record_mapping('conversation', source_id, chatwoot_conversation, metadata: conversation_metadata(conversation, inbox, source_type))
     end
     item.update!(status: :imported, chatwoot_record_type: 'Conversation', chatwoot_record_id: chatwoot_conversation.id)
-    increment_stat('conversations', 'imported') unless already_handled
+    if already_handled
+      reconcile_item_stats('conversation')
+    else
+      increment_stat('conversations', 'imported')
+    end
+
+    return unless import_conversation_messages(conversation, chatwoot_conversation, contact)
 
-    import_source_message(conversation, chatwoot_conversation, contact)
-    import_conversation_parts(conversation, chatwoot_conversation, contact)
     update_conversation_activity(chatwoot_conversation)
   rescue StandardError => e
     raise if e.is_a?(DataImports::Intercom::Client::Error)
 
     fail_item(item, e)
   ensure
-    persist_stats
+    persist_stats unless @import_stopped
   end
 
   def import_stopped?
@@ -184,38 +213,49 @@ class DataImports::Intercom::Importer
     @import_stopped = @data_import.abandoned? || @data_import.completed? || @data_import.completed_with_errors? || stale_import_run?
   end
 
+  def continue_import_with_heartbeat?
+    return false if import_stopped?
+    return true if @data_import.updated_at > HEARTBEAT_INTERVAL.ago
+
+    @data_import.touch if @data_import.updated_at <= HEARTBEAT_INTERVAL.ago
+    true
+  end
+
   def stale_import_run?
     active_run_id = @data_import.active_intercom_import_run_id
     @run_id.present? && active_run_id.present? && active_run_id != @run_id
   end
 
   def import_contact(contact_payload, required_for_conversation: false)
-    source_id = source_id_for(contact_payload)
-    if source_id.present? && (mapping = find_mapping('contact', source_id)) && (mapped_contact = mapping.chatwoot_record)
-      return reuse_mapped_contact(contact_payload, source_id, mapping, mapped_contact)
-    end
+    item = nil
+    with_query_timeout_retry do
+      source_id = source_id_for(contact_payload)
+      if source_id.present? && (mapping = find_mapping('contact', source_id)) && (mapped_contact = mapping.chatwoot_record)
+        return reuse_mapped_contact(contact_payload, source_id, mapping, mapped_contact)
+      end
 
-    contact_payload = retrieve_contact_payload(contact_payload)
-    source_id = source_id_for(contact_payload)
-    already_handled = item_handled?('contact', source_id)
-    item = import_item('contact', source_id, contact_payload)
-    mapping = find_mapping('contact', source_id)
+      contact_payload = retrieve_contact_payload(contact_payload)
+      source_id = source_id_for(contact_payload)
+      already_handled = item_handled?('contact', source_id)
+      item = import_item('contact', source_id, contact_payload)
+      mapping = find_mapping('contact', source_id)
 
-    mapped_contact = mapping&.chatwoot_record
-    if mapped_contact && mapping.data_import_id != @data_import.id
-      skip_already_imported_item(item, mapping, already_handled: already_handled)
-      return mapped_contact
-    end
+      mapped_contact = mapping&.chatwoot_record
+      if mapped_contact && mapping.data_import_id != @data_import.id
+        skip_already_imported_item(item, mapping, already_handled: already_handled)
+        return mapped_contact
+      end
 
-    contact = Contact.transaction do
-      imported_contact = mapped_contact || find_existing_contact(contact_payload) || create_contact(contact_payload)
-      update_existing_contact(imported_contact, contact_payload)
-      record_mapping('contact', source_id, imported_contact, metadata: contact_metadata(contact_payload))
-      item.update!(status: :imported, chatwoot_record_type: 'Contact', chatwoot_record_id: imported_contact.id)
-      imported_contact
+      contact = Contact.transaction do
+        imported_contact = mapped_contact || find_existing_contact(contact_payload) || create_contact(contact_payload)
+        update_existing_contact(imported_contact, contact_payload)
+        record_mapping('contact', source_id, imported_contact, metadata: contact_metadata(contact_payload))
+        item.update!(status: :imported, chatwoot_record_type: 'Contact', chatwoot_record_id: imported_contact.id)
+        imported_contact
+      end
+      increment_stat('contacts', 'imported') unless already_handled
+      contact
     end
-    increment_stat('contacts', 'imported') unless already_handled
-    contact
   rescue StandardError => e
     raise if e.is_a?(DataImports::Intercom::Client::Error)
 
@@ -369,66 +409,291 @@ class DataImports::Intercom::Importer
     end
   end
 
-  def import_source_message(conversation, chatwoot_conversation, contact)
-    source = conversation['source'].to_h
-    return unless source_message_importable?(source)
-
-    message_source_id = "conversation:#{source_id_for(conversation)}:source:#{source['id'].presence || 'initial'}"
-    source_part = source.merge('part_type' => 'source', 'created_at' => conversation['created_at'])
-    if (mapping = find_mapping('message', message_source_id)) && message_mapping_handled?(mapping, source_part)
-      if mapping.data_import_id == @data_import.id
-        reconcile_current_run_message_mapping(chatwoot_conversation, mapping, source_part)
-        return
-      end
-
-      skip_existing_message_mapping(chatwoot_conversation, mapping, source_part)
-      return
-    end
-
-    create_message(chatwoot_conversation, contact, source_part, message_source_id)
-  rescue StandardError => e
-    fail_message(chatwoot_conversation, message_source_id, source_part, e)
-  end
-
-  def import_conversation_parts(conversation, chatwoot_conversation, contact)
+  def import_conversation_messages(conversation, chatwoot_conversation, contact)
     parts_payload = conversation['conversation_parts'].to_h
     parts = Array(parts_payload['conversation_parts'])
+    batch_builder = DataImports::Intercom::MessageBatchBuilder.new(
+      data_import: @data_import,
+      conversation: chatwoot_conversation,
+      source_conversation: conversation
+    )
+    batch = begin
+      with_query_timeout_retry { batch_builder.perform }
+    rescue ActiveRecord::QueryCanceled
+      nil
+    end
+    return import_conversation_messages_individually(conversation, chatwoot_conversation, contact, batch_builder, parts.size) if batch.nil?
+
     record_truncated_conversation_parts(conversation, parts.size)
 
-    parts.each do |part|
-      message_source_id = "conversation:#{source_id_for(conversation)}:part:#{part['id']}"
-      if (mapping = find_mapping('message', message_source_id)) && message_mapping_handled?(mapping, part)
-        if mapping.data_import_id == @data_import.id
-          reconcile_current_run_message_mapping(chatwoot_conversation, mapping, part)
+    batch.entries.each_slice(MESSAGES_PER_BATCH) do |entries|
+      return false unless continue_import_with_heartbeat?
+
+      import_message_batch(chatwoot_conversation, contact, batch_builder, entries)
+      return false if @import_stopped
+    end
+    return false if import_stopped?
+
+    true
+  end
+
+  def import_message_batch(conversation, contact, batch_builder, entries)
+    result = bulk_message_batch_result(conversation, contact, batch_builder, entries)
+    return if result.blank?
+
+    result.current_entries.each do |entry|
+      reconcile_bulk_message_entry(conversation, entry) do
+        reconcile_current_run_message_mapping(conversation, entry.mapping, entry.part)
+      end
+    end
+    result.previous_entries.each do |entry|
+      reconcile_bulk_message_entry(conversation, entry) do
+        skip_existing_message_mapping(conversation, entry.mapping, entry.part)
+      end
+    end
+    result.skipped_entries.each do |entry|
+      reconcile_bulk_message_entry(conversation, entry) { record_bulk_skipped_message(conversation, entry) }
+    end
+    Array(result.failed_entries).each { |entry, error| fail_message(conversation, entry.source_id, entry.part, error) }
+    increment_stat('messages', 'imported', result.imported_entries.size)
+    result.messages.each { |message| reindex_message_for_search(message) }
+  end
+
+  def bulk_message_batch_result(conversation, contact, batch_builder, entries)
+    with_query_timeout_retry do
+      bulk_write_message_entries(conversation, contact, batch_builder, entries)
+    end
+  rescue ActiveRecord::ActiveRecordError
+    fallback_message_entries(conversation, contact, batch_builder, entries) unless @import_stopped
+    nil
+  end
+
+  def fallback_message_entries(conversation, contact, batch_builder, entries)
+    entries.each do |entry|
+      break unless continue_import_with_heartbeat?
+
+      message = fallback_message_entry(conversation, contact, batch_builder, entry)
+      reindex_message_for_search(message) if message.is_a?(Message)
+    end
+  end
+
+  def fallback_message_entry(conversation, contact, batch_builder, entry)
+    with_query_timeout_retry do
+      @data_import.with_lock do
+        if inactive_import_run?
+          @import_stopped = true
           next
         end
 
-        skip_existing_message_mapping(chatwoot_conversation, mapping, part)
+        refreshed_entry = batch_builder.refresh([entry]).entries.first
+        import_message(conversation, contact, refreshed_entry, reindex: false)
+      end
+    end
+  rescue ActiveRecord::ActiveRecordError => e
+    fail_message(conversation, entry.source_id, entry.part, e)
+  end
+
+  def bulk_write_message_entries(conversation, contact, batch_builder, entries)
+    @data_import.with_lock do
+      if inactive_import_run?
+        @import_stopped = true
         next
       end
 
-      create_message(chatwoot_conversation, contact, part, message_source_id)
-    rescue StandardError => e
-      fail_message(chatwoot_conversation, message_source_id, part, e)
+      refreshed_entries = batch_builder.refresh(entries).entries
+      persist_message_entries(conversation, contact, refreshed_entries)
     end
   end
 
-  def create_message(conversation, contact, part, message_source_id)
-    content = content_for(part)
-    return record_skipped_message(conversation, message_source_id, part) if content.blank?
+  def inactive_import_run?
+    @data_import.abandoned? || @data_import.failed? || @data_import.completed? ||
+      @data_import.completed_with_errors? || stale_import_run?
+  end
 
-    attrs = message_attributes(conversation, contact, part, message_source_id, content)
-    message = nil
-    Message.transaction do
-      message = conversation.messages.find_by(source_id: attrs[:source_id])
-      unless message
-        result = Message.insert_all!([attrs], returning: %w[id])
-        message = Message.find(result.rows.first.first)
-      end
-      record_mapping('message', message_source_id, message, metadata: message_metadata(part))
+  def persist_message_entries(conversation, contact, entries)
+    grouped_entries = entries.group_by(&:classification)
+    writable_entries = entries.select do |entry|
+      %i[repairable_stale_mapping existing_message new_message].include?(entry.classification)
     end
+    content_by_source_id = {}
+    attributes_by_source_id = {}
+    failed_entries = []
+    writable_entries.select! do |entry|
+      validate_message_payload!(entry.part)
+      content = content_for(entry.part)
+      content_by_source_id[entry.source_id] = content
+      if content.present? && entry.message.blank?
+        attributes_by_source_id[entry.source_id] = message_attributes(conversation, contact, entry.part, entry.source_id, content)
+      end
+      true
+    rescue InvalidMessagePayloadError => e
+      failed_entries << [entry, e]
+      false
+    end
+    skipped_entries, imported_entries = writable_entries.partition { |entry| content_by_source_id[entry.source_id].blank? }
+    messages = insert_messages(imported_entries, attributes_by_source_id)
+    upsert_message_mappings(conversation, imported_entries, skipped_entries, messages)
+
+    MessageBatchResult.new(
+      imported_entries: imported_entries,
+      skipped_entries: skipped_entries,
+      current_entries: grouped_entries.fetch(:current_import, []),
+      previous_entries: grouped_entries.fetch(:previous_import, []),
+      messages: messages,
+      failed_entries: failed_entries
+    )
+  end
+
+  def insert_messages(entries, attributes_by_source_id)
+    new_entries = entries.reject(&:message)
+    if new_entries.present?
+      attributes = new_entries.map { |entry| attributes_by_source_id.fetch(entry.source_id) }
+      result = Message.insert_all!(attributes, returning: %w[id source_id])
+      inserted_messages = Message.where(id: result.pluck('id')).index_by(&:source_id)
+    end
+
+    entries.map do |entry|
+      entry.message || inserted_messages.fetch("intercom:#{entry.source_id}")
+    end
+  end
+
+  def validate_message_payload!(part)
+    raise InvalidMessagePayloadError, 'Intercom message payload must be an object' unless part.is_a?(Hash)
+
+    %w[author assigned_to event_details].each do |field|
+      value = part[field]
+      next if value.nil? || value.is_a?(Hash)
+
+      raise InvalidMessagePayloadError, "Intercom message #{field} must be an object"
+    end
+
+    participant = part.dig('event_details', 'participant')
+    unless participant.nil? || participant.is_a?(Hash)
+      raise InvalidMessagePayloadError, 'Intercom message event_details.participant must be an object'
+    end
+
+    %w[created_at updated_at].each do |field|
+      value = part[field]
+      valid_timestamp = value.nil? || value.is_a?(Integer) || value.is_a?(Float) ||
+                        (value.is_a?(String) && (value.blank? || value.match?(/\A-?\d+(?:\.\d+)?\z/)))
+      raise InvalidMessagePayloadError, "Intercom message #{field} must be a Unix timestamp" unless valid_timestamp
+
+      timestamp_for(value) if value.present?
+    rescue RangeError
+      raise InvalidMessagePayloadError, "Intercom message #{field} must be a Unix timestamp"
+    end
+
+    %w[body subject].each do |field|
+      value = part[field]
+      next unless value.is_a?(String) && !value.valid_encoding?
+
+      raise InvalidMessagePayloadError, "Intercom message #{field} must use valid encoding"
+    end
+  end
+
+  def upsert_message_mappings(conversation, imported_entries, skipped_entries, messages)
+    now = Time.current
+    mapping_attributes = imported_entries.zip(messages).map do |entry, message|
+      message_mapping_attributes(entry, 'Message', message.id, message_metadata(entry.part), now)
+    end
+    mapping_attributes.concat(skipped_entries.filter_map do |entry|
+      next if entry.mapping
+
+      metadata = message_metadata(entry.part).merge(skipped: true, reason: 'blank_or_unsupported_intercom_part')
+      message_mapping_attributes(entry, 'Conversation', conversation.id, metadata, now)
+    end)
+    return if mapping_attributes.empty?
+
+    DataImportMapping.upsert_all(
+      mapping_attributes,
+      unique_by: MESSAGE_MAPPING_UNIQUE_INDEX,
+      update_only: %i[data_import_id chatwoot_record_type chatwoot_record_id metadata updated_at],
+      record_timestamps: false
+    )
+  end
+
+  def message_mapping_attributes(entry, record_type, record_id, metadata, now)
+    {
+      account_id: @account.id,
+      data_import_id: @data_import.id,
+      source_provider: PROVIDER,
+      source_object_type: 'message',
+      source_object_id: entry.source_id,
+      chatwoot_record_type: record_type,
+      chatwoot_record_id: record_id,
+      metadata: metadata,
+      created_at: entry.mapping&.created_at || now,
+      updated_at: now
+    }
+  end
+
+  def record_bulk_skipped_message(conversation, entry)
+    already_recorded = skip_log_recorded?('message', entry.source_id, SKIPPED_MESSAGE_ERROR_CODE)
+    record_skipped_message_log(conversation, entry.source_id, entry.part)
+    increment_stat('messages', 'skipped') unless already_recorded
+  end
+
+  def reconcile_bulk_message_entry(conversation, entry, &)
+    with_query_timeout_retry(&)
+  rescue StandardError => e
+    fail_message(conversation, entry.source_id, entry.part, e)
+  end
+
+  def import_conversation_messages_individually(conversation, chatwoot_conversation, contact, batch_builder, parts_count)
+    source_entries, part_entries = batch_builder.unprepared_entries.partition { |entry| entry[:part]['part_type'] == 'source' }
+    source_entries.each { |entry| import_unprepared_message(chatwoot_conversation, contact, batch_builder, entry) }
+    record_truncated_conversation_parts(conversation, parts_count)
+
+    part_entries.each do |entry|
+      return false unless continue_import_with_heartbeat?
+
+      import_unprepared_message(chatwoot_conversation, contact, batch_builder, entry)
+    end
+    return false if import_stopped?
+
+    true
+  end
+
+  def import_unprepared_message(conversation, contact, batch_builder, source_entry)
+    entry = with_query_timeout_retry { batch_builder.perform([source_entry]).entries.first }
+    import_message(conversation, contact, entry)
+  rescue StandardError => e
+    fail_message(conversation, source_entry[:source_id], source_entry[:part], e)
+  end
+
+  def import_message(conversation, contact, entry, reindex: true)
+    message = with_query_timeout_retry do
+      Message.transaction(requires_new: true) do
+        case entry.classification
+        when :current_import
+          reconcile_current_run_message_mapping(conversation, entry.mapping, entry.part)
+        when :previous_import
+          skip_existing_message_mapping(conversation, entry.mapping, entry.part)
+        when :repairable_stale_mapping, :existing_message, :new_message
+          create_message(conversation, contact, entry)
+        else
+          raise ArgumentError, "Unsupported Intercom message classification: #{entry.classification}"
+        end
+      end
+    end
+    reindex_message_for_search(message) if reindex && message.is_a?(Message)
+    message
+  rescue StandardError => e
+    fail_message(conversation, entry.source_id, entry.part, e)
+  end
+
+  def create_message(conversation, contact, entry)
+    content = content_for(entry.part)
+    return record_skipped_message(conversation, entry) if content.blank?
+
+    attrs = message_attributes(conversation, contact, entry.part, entry.source_id, content)
+    message = entry.message
+    unless message
+      result = Message.insert_all!([attrs], returning: %w[id])
+      message = Message.find(result.rows.first.first)
+    end
+    record_message_mapping(entry, message)
     increment_stat('messages', 'imported')
-    reindex_message_for_search(message)
     message
   end
 
@@ -440,13 +705,12 @@ class DataImports::Intercom::Importer
     Rails.logger.warn("Intercom import message reindex failed for message #{message.id}: #{e.class} - #{e.message}")
   end
 
-  def record_skipped_message(conversation, message_source_id, part)
-    mapping = find_mapping('message', message_source_id)
-    if mapping
-      already_recorded = skip_log_recorded?('message', message_source_id, SKIPPED_MESSAGE_ERROR_CODE)
-      record_skipped_message_log(conversation, message_source_id, part)
+  def record_skipped_message(conversation, entry)
+    if entry.mapping
+      already_recorded = skip_log_recorded?('message', entry.source_id, SKIPPED_MESSAGE_ERROR_CODE)
+      record_skipped_message_log(conversation, entry.source_id, entry.part)
       increment_stat('messages', 'skipped') unless already_recorded
-      return mapping.chatwoot_record
+      return entry.message
     end
 
     DataImportMapping.create!(
@@ -454,15 +718,30 @@ class DataImports::Intercom::Importer
       data_import: @data_import,
       source_provider: PROVIDER,
       source_object_type: 'message',
-      source_object_id: message_source_id,
+      source_object_id: entry.source_id,
       chatwoot_record_type: 'Conversation',
       chatwoot_record_id: conversation.id,
-      metadata: message_metadata(part).merge(skipped: true, reason: 'blank_or_unsupported_intercom_part')
+      metadata: message_metadata(entry.part).merge(skipped: true, reason: 'blank_or_unsupported_intercom_part')
     )
-    record_skipped_message_log(conversation, message_source_id, part)
+    record_skipped_message_log(conversation, entry.source_id, entry.part)
     increment_stat('messages', 'skipped')
   end
 
+  def record_message_mapping(entry, message)
+    (entry.mapping || DataImportMapping.new(
+      account: @account,
+      source_provider: PROVIDER,
+      source_object_type: 'message',
+      source_object_id: entry.source_id
+    )).tap do |mapping|
+      mapping.data_import = @data_import
+      mapping.chatwoot_record_type = 'Message'
+      mapping.chatwoot_record_id = message.id
+      mapping.metadata = message_metadata(entry.part)
+      mapping.save!
+    end
+  end
+
   def message_attributes(conversation, contact, part, message_source_id, content)
     message_type = message_type_for(part)
     created_at = timestamp_for(part['created_at'])
@@ -503,8 +782,7 @@ class DataImports::Intercom::Importer
   end
 
   def activity_part?(part)
-    part_type = part['part_type'].to_s
-    part_type.present? && REGULAR_MESSAGE_PART_TYPES.exclude?(part_type)
+    DataImports::Intercom::MessageBatchBuilder.activity_part?(part)
   end
 
   def message_content(part)
@@ -629,7 +907,7 @@ class DataImports::Intercom::Importer
     )
     item = import_item('contact', source_id, contact_payload) unless item&.imported?
     item.update!(status: :imported, chatwoot_record_type: 'Contact', chatwoot_record_id: mapped_contact.id)
-    reconcile_item_stats('contact')
+    mark_stat_group_dirty('contacts')
   end
 
   def reconcile_item_stats(source_object_type)
@@ -637,34 +915,37 @@ class DataImports::Intercom::Importer
     group = stat_group_for(source_object_type)
     @stats[group]['imported'] = items.imported.count
     @stats[group]['skipped'] = items.skipped.count
-    persist_stats
   end
 
   def reconcile_current_run_message_mapping(conversation, mapping, part)
     record_skipped_message_log(conversation, mapping.source_object_id, part) if mapping.metadata['skipped']
+    mark_stat_group_dirty('messages')
+  end
 
+  def reconcile_message_stats
     mappings = @data_import.mappings.where(source_provider: PROVIDER, source_object_type: 'message')
     skipped_mappings = mappings.where("metadata ->> 'skipped' = ?", 'true').count
     message_logs = @data_import.import_errors.where(source_object_type: 'message')
     @stats['messages']['imported'] = mappings.count - skipped_mappings
     @stats['messages']['skipped'] = message_logs.where("details ->> 'kind' = ?", 'skipped').count
-    persist_stats
   end
 
   def skip_already_imported_item(item, mapping, already_handled:)
-    item.update!(
-      status: :skipped,
-      chatwoot_record_type: mapping.chatwoot_record_type,
-      chatwoot_record_id: mapping.chatwoot_record_id,
-      last_error_code: ALREADY_IMPORTED_ERROR_CODE,
-      last_error_message: 'Already imported in a previous import.'
-    )
-    record_already_imported_log(
-      data_import_item: item,
-      source_object_type: item.source_object_type,
-      source_object_id: item.source_object_id,
-      mapping: mapping
-    )
+    DataImportItem.transaction do
+      item.update!(
+        status: :skipped,
+        chatwoot_record_type: mapping.chatwoot_record_type,
+        chatwoot_record_id: mapping.chatwoot_record_id,
+        last_error_code: ALREADY_IMPORTED_ERROR_CODE,
+        last_error_message: 'Already imported in a previous import.'
+      )
+      record_already_imported_log(
+        data_import_item: item,
+        source_object_type: item.source_object_type,
+        source_object_id: item.source_object_id,
+        mapping: mapping
+      )
+    end
     increment_stat(stat_group_for(item.source_object_type), 'skipped') unless already_handled
   end
 
@@ -676,13 +957,12 @@ class DataImports::Intercom::Importer
       already_recorded = skip_log_recorded?('message', mapping.source_object_id, ALREADY_IMPORTED_ERROR_CODE)
       record_already_imported_log(source_object_type: 'message', source_object_id: mapping.source_object_id, mapping: mapping)
     end
-    increment_stat('messages', 'skipped') unless already_recorded
-  end
-
-  def message_mapping_handled?(mapping, part)
-    return false if mapping.metadata['skipped'] && activity_part?(part)
-
-    mapping.metadata['skipped'] || mapping.chatwoot_record.present?
+    if already_recorded
+      message_logs = @data_import.import_errors.where(source_object_type: 'message')
+      @stats['messages']['skipped'] = message_logs.where("details ->> 'kind' = ?", 'skipped').count
+    else
+      increment_stat('messages', 'skipped')
+    end
   end
 
   def fail_item(item, error)
@@ -782,7 +1062,7 @@ class DataImports::Intercom::Importer
   end
 
   def source_message_importable?(source)
-    source['body'].present? || source['subject'].present? || source['attachments'].present?
+    DataImports::Intercom::MessageBatchBuilder.source_message_importable?(source)
   end
 
   def skipped_message_log_message(part)
@@ -930,9 +1210,45 @@ class DataImports::Intercom::Importer
     @import_types ||= (@data_import.import_types.presence || DEFAULT_IMPORT_TYPES)
   end
 
-  def increment_stat(group, key)
+  def increment_stat(group, key, amount = 1)
     @stats[group] ||= {}
-    @stats[group][key] = @stats[group][key].to_i + 1
+    @stats[group][key] = @stats[group][key].to_i + amount
+  end
+
+  def mark_stat_group_dirty(group)
+    @dirty_stat_groups[group] = true
+  end
+
+  def reconcile_dirty_stats
+    return if @dirty_stat_groups.empty?
+
+    with_query_timeout_retry do
+      @dirty_stat_groups.each_key do |group|
+        case group
+        when 'contacts'
+          reconcile_item_stats('contact')
+        when 'messages'
+          reconcile_message_stats
+        else
+          raise ArgumentError, "Unsupported Intercom import stat group: #{group}"
+        end
+      end
+      persist_stats
+    end
+    @dirty_stat_groups.clear
+  end
+
+  def with_query_timeout_retry
+    retries = 0
+    begin
+      yield
+    rescue ActiveRecord::QueryCanceled
+      raise if retries >= QUERY_TIMEOUT_RETRY_LIMIT
+
+      retries += 1
+      sleep(rand(QUERY_TIMEOUT_RETRY_DELAY_RANGE))
+      retry
+    end
   end
 
   def update_stat_total(group, total)

app/services/data_imports/intercom/message_batch_builder.rb

@@ -0,0 +1,144 @@
+class DataImports::Intercom::MessageBatchBuilder
+  PROVIDER = 'intercom'.freeze
+  REGULAR_PART_TYPES = %w[comment note source].freeze
+
+  Entry = Struct.new(:source_id, :part, :position, :mapping, :message, :classification, keyword_init: true) do
+    def source?
+      part['part_type'] == 'source'
+    end
+  end
+
+  Batch = Struct.new(:items, keyword_init: true) do
+    def entries
+      items
+    end
+
+    def source_entries
+      items.select(&:source?)
+    end
+
+    def part_entries
+      items.reject(&:source?)
+    end
+  end
+
+  def self.activity_part?(part)
+    part_type = part['part_type'].to_s
+    part_type.present? && REGULAR_PART_TYPES.exclude?(part_type)
+  end
+
+  def self.source_message_importable?(source)
+    source['body'].present? || source['subject'].present? || source['attachments'].present?
+  end
+
+  def initialize(data_import:, conversation:, source_conversation:)
+    @data_import = data_import
+    @account = data_import.account
+    @conversation = conversation
+    @source_conversation = source_conversation
+  end
+
+  def perform(source_entries = unprepared_entries)
+    classify(source_entries)
+  end
+
+  def refresh(entries)
+    classify(entries.map do |entry|
+      { source_id: entry.source_id, part: entry.part, position: entry.position }
+    end)
+  end
+
+  def unprepared_entries
+    ordered_source_entries.map.with_index { |entry, position| entry.merge(position: position) }
+  end
+
+  private
+
+  def classify(source_entries)
+    return Batch.new(items: []) if source_entries.empty?
+
+    mappings = message_mappings(source_entries)
+    messages = messages_for(source_entries, mappings)
+
+    Batch.new(items: source_entries.map.with_index do |source_entry, position|
+      build_entry(source_entry, source_entry.fetch(:position, position), mappings, messages)
+    end)
+  end
+
+  def ordered_source_entries
+    entries = []
+    source = @source_conversation['source'].to_h
+    if self.class.source_message_importable?(source)
+      entries << {
+        source_id: "conversation:#{source_conversation_id}:source:#{source['id'].presence || 'initial'}",
+        part: source.merge('part_type' => 'source', 'created_at' => @source_conversation['created_at'])
+      }
+    end
+
+    conversation_parts.each do |part|
+      entries << { source_id: "conversation:#{source_conversation_id}:part:#{part['id']}", part: part }
+    end
+    entries
+  end
+
+  def conversation_parts
+    Array(@source_conversation.dig('conversation_parts', 'conversation_parts'))
+  end
+
+  def source_conversation_id
+    @source_conversation['id'].presence || @source_conversation['external_id'].presence || @source_conversation['email'].presence
+  end
+
+  def message_mappings(source_entries)
+    DataImportMapping.where(
+      account: @account,
+      source_provider: PROVIDER,
+      source_object_type: 'message',
+      source_object_id: source_entries.pluck(:source_id)
+    ).index_by(&:source_object_id)
+  end
+
+  def messages_for(source_entries, mappings)
+    mapped_message_ids = mappings.values.filter_map do |mapping|
+      mapping.chatwoot_record_id if mapping.chatwoot_record_type == 'Message'
+    end
+    chatwoot_source_ids = source_entries.map { |entry| "intercom:#{entry[:source_id]}" }
+    messages = Message.where(id: mapped_message_ids).or(
+      Message.where(conversation_id: @conversation.id, source_id: chatwoot_source_ids)
+    ).to_a
+
+    {
+      by_id: messages.index_by(&:id),
+      by_source_id: messages.index_by(&:source_id)
+    }
+  end
+
+  def build_entry(source_entry, position, mappings, messages)
+    source_id = source_entry[:source_id]
+    mapping = mappings[source_id]
+    mapped_message = messages[:by_id][mapping.chatwoot_record_id] if mapping&.chatwoot_record_type == 'Message'
+    existing_message = messages[:by_source_id]["intercom:#{source_id}"]
+
+    Entry.new(
+      source_id: source_id,
+      part: source_entry[:part],
+      position: position,
+      mapping: mapping,
+      message: mapped_message || existing_message,
+      classification: classification_for(mapping, mapped_message, existing_message, source_entry[:part])
+    )
+  end
+
+  def classification_for(mapping, mapped_message, existing_message, part)
+    return existing_message.present? ? :existing_message : :new_message if mapping.blank?
+    return :repairable_stale_mapping unless mapping_handled?(mapping, mapped_message, part)
+
+    mapping.data_import_id == @data_import.id ? :current_import : :previous_import
+  end
+
+  def mapping_handled?(mapping, mapped_message, part)
+    return false if mapping.metadata['skipped'] && self.class.activity_part?(part)
+
+    mapping.metadata['skipped'] || mapped_message.present?
+  end
+end

app/services/data_imports/intercom/retry_service.rb

@@ -0,0 +1,28 @@
+class DataImports::Intercom::RetryService
+  attr_reader :data_import
+
+  def initialize(account:, data_import:)
+    @account = account
+    @data_import = data_import
+  end
+
+  def perform
+    @account.with_lock do
+      @data_import.with_lock do
+        next :not_stalled unless @data_import.stalled?
+        next :active_import_exists if another_active_import?
+        next :access_token_missing if @data_import.access_token.blank?
+
+        @data_import.assign_active_intercom_import_run_id
+        @data_import.update!(status: :pending)
+        :enqueue
+      end
+    end
+  end
+
+  private
+
+  def another_active_import?
+    @account.data_imports.active_intercom.where.not(id: @data_import.id).exists?
+  end
+end

app/views/api/v1/accounts/data_imports/_data_import.json.jbuilder

@@ -5,6 +5,7 @@ json.source_type data_import.source_type
 json.source_provider data_import.source_provider
 json.import_types data_import.import_types
 json.status data_import.status
+json.stalled data_import.stalled?
 json.total_records data_import.total_records
 json.processed_records data_import.processed_records
 json.stats data_import.stats

config/routes.rb

@@ -230,6 +230,7 @@ Rails.application.routes.draw do
             end
             member do
               post :start
+              post :retry, action: :retry_import
               post :abandon
               get :error_logs
               get :skip_logs

spec/models/data_import_spec.rb

@@ -64,4 +64,36 @@ RSpec.describe DataImport do
       expect(data_import.abandoned_at).to be_nil
     end
   end
+
+  describe '#stalled?' do
+    let(:account) { create(:account) }
+
+    it 'identifies active Intercom imports without updates for fifteen minutes', :aggregate_failures do
+      freeze_time do
+        processing_import = create(:data_import, :intercom, account: account, status: :processing)
+        pending_import = create(:data_import, :intercom, account: account, status: :pending)
+        processing_import.update!(updated_at: 15.minutes.ago)
+        pending_import.update!(updated_at: 15.minutes.ago)
+
+        expect(processing_import.reload).to be_stalled
+        expect(pending_import.reload).to be_stalled
+      end
+    end
+
+    it 'does not identify recent or terminal Intercom imports as stalled', :aggregate_failures do
+      recent_import = create(:data_import, :intercom, account: account, status: :processing)
+      completed_import = create(:data_import, :intercom, account: account, status: :completed)
+      completed_import.update!(updated_at: 1.hour.ago)
+
+      expect(recent_import).not_to be_stalled
+      expect(completed_import.reload).not_to be_stalled
+    end
+
+    it 'does not identify legacy imports as stalled' do
+      legacy_import = create(:data_import, account: account, status: :processing)
+      legacy_import.update!(updated_at: 1.hour.ago)
+
+      expect(legacy_import.reload).not_to be_stalled
+    end
+  end
 end

spec/requests/api/v1/accounts/data_imports_spec.rb

@@ -209,6 +209,63 @@ RSpec.describe 'Data Imports API', type: :request do
     end
   end
 
+  describe 'POST /api/v1/accounts/:account_id/data_imports/:id/retry' do
+    let(:data_import) { create(:data_import, :intercom, account: account, status: :processing, started_at: 2.hours.ago) }
+
+    it 'resumes a stalled import with a new run identifier while preserving progress', :aggregate_failures do
+      started_at = data_import.started_at
+      data_import.update!(
+        cursor: { 'conversations' => { 'starting_after' => 'cursor-1' } },
+        stats: { 'conversations' => { 'imported' => 20 } },
+        source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'previous-run' },
+        updated_at: 16.minutes.ago
+      )
+
+      expect do
+        post retry_api_v1_account_data_import_url(account_id: account.id, id: data_import.id),
+             headers: admin.create_new_auth_token,
+             as: :json
+      end.to have_enqueued_job(DataImports::Intercom::ImportJob).with(data_import, a_kind_of(String))
+
+      expect(response).to have_http_status(:ok)
+      expect(response.parsed_body).to include('status' => 'pending', 'stalled' => false)
+      expect(data_import.reload.started_at).to eq(started_at)
+      expect(data_import.cursor.dig('conversations', 'starting_after')).to eq('cursor-1')
+      expect(data_import.stats.dig('conversations', 'imported')).to eq(20)
+      expect(data_import.active_intercom_import_run_id).not_to eq('previous-run')
+    end
+
+    it 'rejects duplicate retries after the import becomes active again' do
+      data_import.update!(updated_at: 16.minutes.ago)
+      post retry_api_v1_account_data_import_url(account_id: account.id, id: data_import.id),
+           headers: admin.create_new_auth_token,
+           as: :json
+
+      expect do
+        post retry_api_v1_account_data_import_url(account_id: account.id, id: data_import.id),
+             headers: admin.create_new_auth_token,
+             as: :json
+      end.not_to have_enqueued_job(DataImports::Intercom::ImportJob)
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(response.parsed_body['message']).to eq('This Intercom import is no longer stalled.')
+    end
+
+    it 'rejects retry while another Intercom import is active' do
+      data_import.update!(updated_at: 16.minutes.ago)
+      create(:data_import, :intercom, account: account, status: :processing)
+
+      expect do
+        post retry_api_v1_account_data_import_url(account_id: account.id, id: data_import.id),
+             headers: admin.create_new_auth_token,
+             as: :json
+      end.not_to have_enqueued_job(DataImports::Intercom::ImportJob)
+
+      expect(response).to have_http_status(:unprocessable_entity)
+      expect(response.parsed_body['message']).to eq('Another Intercom import is already in progress.')
+    end
+  end
+
   describe 'POST /api/v1/accounts/:account_id/data_imports/:id/abandon' do
     let(:data_import) { create(:data_import, :intercom, account: account) }
 
@@ -283,6 +340,7 @@ RSpec.describe 'Data Imports API', type: :request do
         'id' => data_import.id,
         'name' => 'July Intercom migration',
         'source_provider' => 'intercom',
+        'stalled' => false,
         'import_errors_count' => 1,
         'skip_logs_count' => 1
       )

spec/services/data_imports/intercom/importer_spec.rb

@@ -66,12 +66,12 @@ RSpec.describe DataImports::Intercom::Importer do
   before do
     account.enable_features!('data_import')
     allow(DataImports::Intercom::Client).to receive(:new).with(access_token: 'intercom-token').and_return(client)
-    allow(client).to receive(:list_contacts).with(starting_after: nil).and_return(
+    allow(client).to receive(:list_contacts).with(starting_after: nil, per_page: 50).and_return(
       'data' => [contact_payload],
       'total_count' => 1,
       'pages' => { 'next' => nil }
     )
-    allow(client).to receive(:list_conversations).with(starting_after: nil).and_return(
+    allow(client).to receive(:list_conversations).with(starting_after: nil, per_page: 10).and_return(
       'conversations' => [{ 'id' => 'conversation_1' }],
       'total_count' => 1,
       'pages' => { 'next' => nil }
@@ -116,6 +116,275 @@ RSpec.describe DataImports::Intercom::Importer do
     expect(DataImportMapping.where(data_import: data_import).count).to eq(5)
   end
 
+  it 'writes a normal conversation with one message insert and one mapping upsert', :aggregate_failures do
+    importer = described_class.new(data_import: data_import)
+    message_batch_sizes = []
+    mapping_batch_sizes = []
+    mapping_upsert_options = []
+    allow(Message).to receive(:insert_all!).and_wrap_original do |method, records, **kwargs|
+      message_batch_sizes << records.size
+      method.call(records, **kwargs)
+    end
+    allow(DataImportMapping).to receive(:upsert_all).and_wrap_original do |method, records, **kwargs|
+      mapping_batch_sizes << records.size
+      mapping_upsert_options << kwargs
+      method.call(records, **kwargs)
+    end
+    expect(importer).not_to receive(:create_message)
+
+    importer.perform
+
+    expect(message_batch_sizes).to eq([3])
+    expect(mapping_batch_sizes).to eq([3])
+    expect(mapping_upsert_options).to contain_exactly(
+      include(unique_by: described_class::MESSAGE_MAPPING_UNIQUE_INDEX, record_timestamps: false)
+    )
+    expect(account.messages.count).to eq(3)
+    expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+  end
+
+  it 'preserves provider order when imported messages share a timestamp' do
+    equal_timestamp_conversation = conversation_payload.deep_dup
+    equal_timestamp_conversation['conversation_parts']['conversation_parts'].each do |part|
+      part['created_at'] = conversation_payload['created_at']
+      part['updated_at'] = conversation_payload['created_at']
+    end
+    allow(client).to receive(:retrieve_conversation).with('conversation_1').and_return(equal_timestamp_conversation)
+
+    described_class.new(data_import: data_import).perform
+
+    conversation = account.conversations.find_by!(identifier: 'intercom:conversation_1')
+    expect(conversation.messages.order(:created_at, :id).pluck(:source_id)).to eq(
+      %w[
+        intercom:conversation:conversation_1:source:source_1
+        intercom:conversation:conversation_1:part:part_1
+        intercom:conversation:conversation_1:part:part_2
+      ]
+    )
+  end
+
+  it 'writes conversations in batches of at most 100 messages', :aggregate_failures do
+    bulk_conversation = conversation_payload.deep_dup
+    template_part = bulk_conversation.dig('conversation_parts', 'conversation_parts').first
+    bulk_conversation['conversation_parts']['conversation_parts'] = Array.new(205) do |index|
+      template_part.merge(
+        'id' => "part_#{index + 1}",
+        'created_at' => 1_700_000_100 + index,
+        'updated_at' => 1_700_000_100 + index
+      )
+    end
+    allow(client).to receive(:retrieve_conversation).with('conversation_1').and_return(bulk_conversation)
+    message_batch_sizes = []
+    mapping_batch_sizes = []
+    allow(Message).to receive(:insert_all!).and_wrap_original do |method, records, **kwargs|
+      message_batch_sizes << records.size
+      method.call(records, **kwargs)
+    end
+    allow(DataImportMapping).to receive(:upsert_all).and_wrap_original do |method, records, **kwargs|
+      mapping_batch_sizes << records.size
+      method.call(records, **kwargs)
+    end
+    importer = described_class.new(data_import: data_import)
+    expect(importer).to receive(:update_conversation_activity).once.and_call_original
+
+    importer.import_conversations_page
+
+    expect(message_batch_sizes).to eq([100, 100, 6])
+    expect(mapping_batch_sizes).to eq([100, 100, 6])
+    expect(account.messages.order(:created_at).pick(:source_id)).to eq('intercom:conversation:conversation_1:source:source_1')
+    expect(account.messages.count).to eq(206)
+    expect(data_import.reload.stats.dig('messages', 'imported')).to eq(206)
+  end
+
+  context 'when a bulk message chunk fails' do
+    it 'retries a query timeout once and keeps the successful bulk result', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      mapping_attempts = 0
+      allow(importer).to receive(:sleep)
+      allow(DataImportMapping).to receive(:upsert_all).and_wrap_original do |method, records, **kwargs|
+        mapping_attempts += 1
+        raise ActiveRecord::QueryCanceled, 'statement timeout' if mapping_attempts == 1
+
+        method.call(records, **kwargs)
+      end
+      expect(importer).not_to receive(:fallback_message_entries)
+
+      importer.perform
+
+      expect(mapping_attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(account.messages.count).to eq(3)
+      expect(data_import.mappings.where(source_object_type: 'message').count).to eq(3)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+    end
+
+    it 'falls back individually after the query timeout retry is exhausted', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      mapping_attempts = 0
+      reindex_transaction_depths = []
+      transaction_depth_before_import = Message.connection.open_transactions
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:fallback_message_entries).and_call_original
+      allow(importer).to receive(:create_message).and_call_original
+      allow(importer).to receive(:reindex_message_for_search).and_wrap_original do |method, message|
+        reindex_transaction_depths << Message.connection.open_transactions
+        method.call(message)
+      end
+      allow(DataImportMapping).to receive(:upsert_all) do
+        mapping_attempts += 1
+        raise ActiveRecord::QueryCanceled, 'statement timeout'
+      end
+
+      importer.perform
+
+      expect(mapping_attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(importer).to have_received(:fallback_message_entries).once
+      expect(importer).to have_received(:create_message).exactly(3).times
+      expect(account.messages.count).to eq(3)
+      expect(data_import.mappings.where(source_object_type: 'message').count).to eq(3)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+      expect(reindex_transaction_depths).to all(eq(transaction_depth_before_import))
+    end
+
+    it 'falls back immediately for a non-timeout database error', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      mapping_attempts = 0
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:fallback_message_entries).and_call_original
+      allow(DataImportMapping).to receive(:upsert_all) do
+        mapping_attempts += 1
+        raise ActiveRecord::StatementInvalid, 'bulk mapping failed'
+      end
+
+      importer.perform
+
+      expect(mapping_attempts).to eq(1)
+      expect(importer).not_to have_received(:sleep)
+      expect(importer).to have_received(:fallback_message_entries).once
+      expect(account.messages.count).to eq(3)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+    end
+
+    it 'refreshes fallback entries when another worker repairs a message', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      allow(importer).to receive(:bulk_write_message_entries).and_raise(ActiveRecord::StatementInvalid, 'bulk failed')
+      allow(importer).to receive(:fallback_message_entries).and_wrap_original do |method, conversation, contact, batch_builder, entries|
+        source_entry = entries.first
+        message = create(
+          :message,
+          account: account,
+          inbox: conversation.inbox,
+          conversation: conversation,
+          source_id: "intercom:#{source_entry.source_id}",
+          created_at: Time.zone.at(source_entry.part['created_at']),
+          updated_at: Time.zone.at(source_entry.part['created_at'])
+        )
+        DataImportMapping.create!(
+          account: account,
+          data_import: data_import,
+          source_provider: 'intercom',
+          source_object_type: 'message',
+          source_object_id: source_entry.source_id,
+          chatwoot_record_type: 'Message',
+          chatwoot_record_id: message.id,
+          metadata: {}
+        )
+        method.call(conversation, contact, batch_builder, entries)
+      end
+
+      importer.perform
+
+      source_id = 'intercom:conversation:conversation_1:source:source_1'
+      expect(account.messages.where(source_id: source_id).count).to eq(1)
+      expect(account.messages.count).to eq(3)
+      expect(data_import.mappings.where(source_object_type: 'message').count).to eq(3)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+    end
+
+    it 'retries a fallback refresh timeout after the lock transaction rolls back', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      refresh_attempts = 0
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:bulk_write_message_entries).and_raise(ActiveRecord::StatementInvalid, 'bulk failed')
+      allow(DataImports::Intercom::MessageBatchBuilder).to receive(:new).and_wrap_original do |method, **kwargs|
+        method.call(**kwargs).tap do |batch_builder|
+          allow(batch_builder).to receive(:refresh).and_wrap_original do |refresh, entries|
+            refresh_attempts += 1
+            raise ActiveRecord::QueryCanceled, 'statement timeout' if refresh_attempts == 1
+
+            refresh.call(entries)
+          end
+        end
+      end
+
+      importer.perform
+
+      expect(refresh_attempts).to eq(4)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(account.messages.count).to eq(3)
+      expect(data_import.mappings.where(source_object_type: 'message').count).to eq(3)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+    end
+  end
+
+  it 'isolates a malformed message payload while importing valid messages', :aggregate_failures do
+    malformed_conversation = conversation_payload.deep_dup
+    malformed_conversation['source']['subject'] = nil
+    malformed_conversation['source']['body'] = nil
+    malformed_conversation.dig('conversation_parts', 'conversation_parts').first['created_at'] = { 'unexpected' => true }
+    allow(client).to receive(:retrieve_conversation).with('conversation_1').and_return(malformed_conversation)
+    importer = described_class.new(data_import: data_import)
+    expect(importer).not_to receive(:fallback_message_entries)
+
+    importer.perform
+
+    expect(account.messages.pluck(:source_id)).to eq(['intercom:conversation:conversation_1:part:part_2'])
+    error = data_import.import_errors.find_by!(
+      source_object_type: 'message',
+      source_object_id: 'conversation:conversation_1:part:part_1'
+    )
+    expect(error).to have_attributes(
+      error_code: described_class::InvalidMessagePayloadError.name,
+      message: 'Intercom message created_at must be a Unix timestamp'
+    )
+    expect(data_import.import_errors.where(source_object_type: 'message').count).to eq(1)
+    expect(data_import.reload).to be_completed_with_errors
+    expect(data_import.stats.dig('messages', 'imported')).to eq(1)
+    expect(data_import.stats.dig('errors', 'count')).to eq(1)
+  end
+
+  it 'isolates an out-of-range message timestamp while importing valid messages', :aggregate_failures do
+    malformed_conversation = conversation_payload.deep_dup
+    malformed_conversation['source']['subject'] = nil
+    malformed_conversation['source']['body'] = nil
+    malformed_conversation.dig('conversation_parts', 'conversation_parts').first['created_at'] = Float::INFINITY
+    allow(client).to receive(:retrieve_conversation).with('conversation_1').and_return(malformed_conversation)
+    importer = described_class.new(data_import: data_import)
+    expect(importer).not_to receive(:fallback_message_entries)
+
+    importer.perform
+
+    expect(account.messages.pluck(:source_id)).to eq(['intercom:conversation:conversation_1:part:part_2'])
+    error = data_import.import_errors.find_by!(
+      source_object_type: 'message',
+      source_object_id: 'conversation:conversation_1:part:part_1'
+    )
+    expect(error).to have_attributes(
+      error_code: described_class::InvalidMessagePayloadError.name,
+      message: 'Intercom message created_at must be a Unix timestamp'
+    )
+    expect(data_import.import_errors.where(source_object_type: 'message').count).to eq(1)
+    expect(data_import.reload).to be_completed_with_errors
+    expect(data_import.stats.dig('messages', 'imported')).to eq(1)
+    expect(data_import.stats.dig('errors', 'count')).to eq(1)
+  end
+
   it 'imports historical records without dispatching record events or outbound side effects', :aggregate_failures do
     dispatched_events = []
     allow(Rails.configuration.dispatcher).to receive(:dispatch) do |event_name, *_args|
@@ -188,14 +457,49 @@ RSpec.describe DataImports::Intercom::Importer do
     expect(item.metadata['message_total_contribution']).to eq(3)
   end
 
+  it 'uses smaller conversation pages while retaining the contact page size' do
+    importer = described_class.new(data_import: data_import)
+
+    importer.import_contacts_page
+    importer.import_conversations_page
+
+    expect(client).to have_received(:list_contacts).with(starting_after: nil, per_page: 50)
+    expect(client).to have_received(:list_conversations).with(starting_after: nil, per_page: 10)
+  end
+
   it 'reconciles imported message stats from same-run mappings on retry' do
     described_class.new(data_import: data_import).import_conversations_page
     stats = data_import.reload.stats.deep_dup
     stats['messages']['imported'] = 0
     data_import.update!(stats: stats)
+    importer = described_class.new(data_import: data_import)
+    expect(importer).to receive(:reconcile_message_stats).once.ordered.and_call_original
+    expect(importer).to receive(:update_cursor).with('conversations', nil).once.ordered.and_call_original
 
+    importer.import_conversations_page
+
+    expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+  end
+
+  it 'retries a query timeout during deferred message stats reconciliation', :aggregate_failures do
     described_class.new(data_import: data_import).import_conversations_page
+    stats = data_import.reload.stats.deep_dup
+    stats['messages']['imported'] = 0
+    data_import.update!(stats: stats)
+    importer = described_class.new(data_import: data_import)
+    reconciliation_attempts = 0
+    allow(importer).to receive(:sleep)
+    allow(importer).to receive(:reconcile_message_stats).and_wrap_original do |method|
+      reconciliation_attempts += 1
+      raise ActiveRecord::QueryCanceled, 'statement timeout' if reconciliation_attempts == 1
 
+      method.call
+    end
+
+    importer.import_conversations_page
+
+    expect(reconciliation_attempts).to eq(2)
+    expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
     expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
   end
 
@@ -203,13 +507,19 @@ RSpec.describe DataImports::Intercom::Importer do
     allow(ChatwootApp).to receive(:advanced_search_allowed?).and_return(true)
     allow(ChatwootApp).to receive(:chatwoot_cloud?).and_return(false)
     reindexed_message_ids = []
+    reindex_transaction_depths = []
+    transaction_depth_before_import = Message.connection.open_transactions
     original_reindex_for_search = Message.instance_method(:reindex_for_search)
-    Message.define_method(:reindex_for_search) { reindexed_message_ids << id }
+    Message.define_method(:reindex_for_search) do
+      reindexed_message_ids << id
+      reindex_transaction_depths << self.class.connection.open_transactions
+    end
     Message.__send__(:private, :reindex_for_search)
 
     described_class.new(data_import: data_import).perform
 
     expect(reindexed_message_ids).to match_array(Message.where(account_id: account.id).pluck(:id))
+    expect(reindex_transaction_depths).to all(eq(transaction_depth_before_import))
   ensure
     Message.define_method(:reindex_for_search, original_reindex_for_search)
     Message.__send__(:private, :reindex_for_search)
@@ -267,7 +577,7 @@ RSpec.describe DataImports::Intercom::Importer do
     it 'stops an in-flight page when a newer import run takes over', :aggregate_failures do
       run_id = 'intercom-run-1'
       data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
-      allow(client).to receive(:list_conversations).with(starting_after: nil).and_return(
+      allow(client).to receive(:list_conversations).with(starting_after: nil, per_page: 10).and_return(
         'conversations' => [{ 'id' => 'conversation_1' }, { 'id' => 'conversation_2' }],
         'pages' => { 'next' => { 'starting_after' => 'next-conversation-cursor' } }
       )
@@ -285,6 +595,165 @@ RSpec.describe DataImports::Intercom::Importer do
       expect(data_import.reload.cursor.dig('conversations', 'starting_after')).to be_nil
     end
 
+    it 'heartbeats at most once per minute while processing conversation message batches' do
+      freeze_time do
+        started_at = Time.current
+        long_conversation = conversation_payload.deep_dup
+        template_part = long_conversation.dig('conversation_parts', 'conversation_parts').first
+        long_conversation['conversation_parts']['conversation_parts'] = Array.new(400) do |index|
+          template_part.merge('id' => "part_#{index + 1}")
+        end
+        allow(client).to receive(:retrieve_conversation).with('conversation_1').and_return(long_conversation)
+        heartbeat_times = []
+        allow(data_import).to receive(:touch).and_wrap_original do |method|
+          heartbeat_times << Time.current
+          method.call
+        end
+        importer = described_class.new(data_import: data_import)
+        empty_result = described_class::MessageBatchResult.new(
+          imported_entries: [],
+          skipped_entries: [],
+          current_entries: [],
+          previous_entries: [],
+          messages: []
+        )
+        allow(importer).to receive(:bulk_write_message_entries) do
+          travel 30.seconds
+          empty_result
+        end
+
+        importer.import_conversations_page
+
+        expect(heartbeat_times).to eq([started_at + 1.minute, started_at + 2.minutes])
+        expect(importer).to have_received(:bulk_write_message_entries).exactly(5).times
+      end
+    end
+
+    it 'stops batches without heartbeating or persisting stale stats when a newer run takes over', :aggregate_failures do
+      freeze_time do
+        run_id = 'intercom-run-1'
+        data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+        long_conversation = conversation_payload.deep_dup
+        template_part = long_conversation.dig('conversation_parts', 'conversation_parts').first
+        long_conversation['conversation_parts']['conversation_parts'] = Array.new(100) do |index|
+          template_part.merge('id' => "part_#{index + 1}")
+        end
+        allow(client).to receive(:retrieve_conversation).with('conversation_1').and_return(long_conversation)
+        allow(data_import).to receive(:touch).and_call_original
+        importer = described_class.new(data_import: data_import, run_id: run_id)
+        batch_write_count = 0
+        allow(importer).to receive(:bulk_write_message_entries).and_wrap_original do |method, *args|
+          result = method.call(*args)
+          batch_write_count += 1
+          if batch_write_count == 1
+            DataImport.find(data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'new-run' })
+          end
+          result
+        end
+
+        importer.import_conversations_page
+
+        expect(importer).to have_received(:bulk_write_message_entries).once
+        expect(data_import).not_to have_received(:touch)
+        expect(data_import.reload.stats.dig('conversations', 'imported')).to eq(0)
+        expect(account.messages.count).to eq(100)
+      end
+    end
+
+    it 'does not persist stale stats when a newer run takes over during the final batch', :aggregate_failures do
+      run_id = 'intercom-run-1'
+      data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+      importer = described_class.new(data_import: data_import, run_id: run_id)
+      allow(importer).to receive(:bulk_write_message_entries).and_wrap_original do |method, *args|
+        method.call(*args).tap do
+          DataImport.find(data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'new-run' })
+        end
+      end
+
+      importer.import_conversations_page
+
+      conversation = account.conversations.find_by!(identifier: 'intercom:conversation_1')
+      expect(conversation.messages.count).to eq(3)
+      expect(data_import.reload.stats.dig('conversations', 'imported')).to eq(0)
+    end
+
+    it 'does not persist stale stats when a newer run takes over during the final prefetch fallback entry', :aggregate_failures do
+      run_id = 'intercom-run-1'
+      data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+      importer = described_class.new(data_import: data_import, run_id: run_id)
+      allow(importer).to receive(:sleep)
+      allow(DataImports::Intercom::MessageBatchBuilder).to receive(:new).and_wrap_original do |method, **kwargs|
+        method.call(**kwargs).tap do |batch_builder|
+          allow(batch_builder).to receive(:perform).and_wrap_original do |perform, *args|
+            raise ActiveRecord::QueryCanceled, 'statement timeout' if args.empty?
+
+            perform.call(*args)
+          end
+        end
+      end
+      allow(importer).to receive(:import_unprepared_message).and_wrap_original do |method, *args|
+        method.call(*args).tap do
+          source_entry = args.last
+          next unless source_entry.dig(:part, 'id') == 'part_2'
+
+          DataImport.find(data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'new-run' })
+        end
+      end
+      expect(importer).not_to receive(:update_conversation_activity)
+
+      importer.import_conversations_page
+
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(importer).to have_received(:import_unprepared_message).exactly(3).times
+      expect(account.messages.count).to eq(3)
+      expect(data_import.reload.stats).to include(
+        'conversations' => include('imported' => 0),
+        'messages' => include('imported' => 0)
+      )
+    end
+
+    it 'stops individual fallback entries when a newer run takes over', :aggregate_failures do
+      run_id = 'intercom-run-1'
+      data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+      importer = described_class.new(data_import: data_import, run_id: run_id)
+      allow(importer).to receive(:bulk_write_message_entries).and_raise(ActiveRecord::StatementInvalid, 'bulk failed')
+      allow(importer).to receive(:fallback_message_entry).and_wrap_original do |method, *args|
+        method.call(*args).tap do
+          DataImport.find(data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'new-run' })
+        end
+      end
+
+      importer.import_conversations_page
+
+      expect(importer).to have_received(:fallback_message_entry).once
+      expect(account.messages.count).to eq(1)
+      expect(data_import.reload.stats.dig('conversations', 'imported')).to eq(0)
+    end
+
+    it 'reconciles conversation stats when a superseded run is retried', :aggregate_failures do
+      freeze_time do
+        run_id = 'intercom-run-1'
+        next_run_id = 'intercom-run-2'
+        data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+        importer = described_class.new(data_import: data_import, run_id: run_id)
+        allow(importer).to receive(:bulk_write_message_entries).and_wrap_original do |method, *args|
+          method.call(*args).tap do
+            DataImport.find(data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => next_run_id })
+          end
+        end
+
+        importer.import_conversations_page
+        expect(data_import.reload.stats.dig('conversations', 'imported')).to eq(0)
+
+        retry_importer = described_class.new(data_import: data_import, run_id: next_run_id)
+        retry_importer.import_conversations_page
+        retry_importer.finish!
+
+        expect(data_import.reload.stats.dig('conversations', 'imported')).to eq(1)
+        expect(data_import.processed_records).to eq(5)
+      end
+    end
+
     it 'rolls back a newly inserted conversation when mapping persistence fails', :aggregate_failures do
       importer = described_class.new(data_import: data_import)
       allow(importer).to receive(:record_mapping).and_wrap_original do |method, object_type, source_id, record, metadata:|
@@ -322,10 +791,11 @@ RSpec.describe DataImports::Intercom::Importer do
 
     it 'rolls back a newly inserted message when mapping persistence fails', :aggregate_failures do
       importer = described_class.new(data_import: data_import)
-      allow(importer).to receive(:record_mapping).and_wrap_original do |method, object_type, source_id, record, metadata:|
-        raise StandardError, 'mapping failed' if object_type == 'message'
+      allow(DataImportMapping).to receive(:upsert_all).and_raise(ActiveRecord::StatementInvalid, 'bulk mapping failed')
+      allow(importer).to receive(:record_message_mapping).and_wrap_original do |method, entry, message|
+        raise StandardError, 'mapping failed' if entry.source_id == 'conversation:conversation_1:source:source_1'
 
-        method.call(object_type, source_id, record, metadata: metadata)
+        method.call(entry, message)
       end
 
       importer.import_conversations_page
@@ -338,6 +808,81 @@ RSpec.describe DataImports::Intercom::Importer do
       )
       expect(error).to have_attributes(error_code: 'StandardError', message: 'mapping failed')
     end
+
+    it 'retries a contact query timeout after rolling back the first transaction', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      mapping_attempts = 0
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:record_mapping).and_wrap_original do |method, object_type, source_id, record, metadata:|
+        if object_type == 'contact'
+          mapping_attempts += 1
+          raise ActiveRecord::QueryCanceled, 'statement timeout' if mapping_attempts == 1
+        end
+
+        method.call(object_type, source_id, record, metadata: metadata)
+      end
+
+      importer.import_contacts_page
+
+      expect(mapping_attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(account.contacts.where(email: 'customer@example.com').count).to eq(1)
+      expect(data_import.mappings.where(source_object_type: 'contact', source_object_id: 'contact_1').count).to eq(1)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('contacts', 'imported')).to eq(1)
+    end
+
+    it 'retries a message query timeout after rolling back the first transaction', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      mapping_attempts = 0
+      target_source_id = 'conversation:conversation_1:part:part_1'
+      allow(DataImportMapping).to receive(:upsert_all).and_raise(ActiveRecord::StatementInvalid, 'bulk unavailable')
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:record_message_mapping).and_wrap_original do |method, entry, message|
+        if entry.source_id == target_source_id
+          mapping_attempts += 1
+          raise ActiveRecord::QueryCanceled, 'statement timeout' if mapping_attempts == 1
+        end
+
+        method.call(entry, message)
+      end
+
+      importer.import_conversations_page
+
+      conversation = account.conversations.find_by!(identifier: 'intercom:conversation_1')
+      expect(mapping_attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(conversation.messages.where(source_id: "intercom:#{target_source_id}").count).to eq(1)
+      expect(data_import.mappings.where(source_object_type: 'message', source_object_id: target_source_id).count).to eq(1)
+      expect(data_import.import_errors).to be_empty
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
+    end
+
+    it 'records one message failure only after the query timeout retry is exhausted', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      mapping_attempts = 0
+      target_source_id = 'conversation:conversation_1:part:part_1'
+      allow(DataImportMapping).to receive(:upsert_all).and_raise(ActiveRecord::StatementInvalid, 'bulk unavailable')
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:record_message_mapping).and_wrap_original do |method, entry, message|
+        if entry.source_id == target_source_id
+          mapping_attempts += 1
+          raise ActiveRecord::QueryCanceled, 'statement timeout'
+        end
+
+        method.call(entry, message)
+      end
+
+      importer.import_conversations_page
+
+      conversation = account.conversations.find_by!(identifier: 'intercom:conversation_1')
+      error = data_import.import_errors.find_by!(source_object_type: 'message', source_object_id: target_source_id)
+      expect(mapping_attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(conversation.messages.where(source_id: "intercom:#{target_source_id}")).to be_empty
+      expect(error).to have_attributes(error_code: 'ActiveRecord::QueryCanceled', message: 'statement timeout')
+      expect(data_import.reload.stats.dig('errors', 'count')).to eq(1)
+    end
   end
 
   describe '#finish!' do
@@ -373,6 +918,26 @@ RSpec.describe DataImports::Intercom::Importer do
       expect(data_import.last_error_at).to be_nil
       expect(data_import.import_errors.exists?).to be(false)
     end
+
+    it 'does not fail an import after a newer run takes over', :aggregate_failures do
+      run_id = 'intercom-run-1'
+      data_import.update!(
+        status: :processing,
+        source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id }
+      )
+      importer = described_class.new(data_import: data_import, run_id: run_id)
+
+      DataImport.find(data_import.id).update!(
+        status: :pending,
+        source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'intercom-run-2' }
+      )
+
+      importer.fail!(StandardError.new('boom'))
+
+      expect(data_import.reload).to be_pending
+      expect(data_import.last_error_at).to be_nil
+      expect(data_import.import_errors.exists?).to be(false)
+    end
   end
 
   context 'when the Intercom records were imported by an earlier run' do
@@ -404,6 +969,60 @@ RSpec.describe DataImports::Intercom::Importer do
         'message' => 3
       )
       expect(next_data_import.import_errors.skip_logs.pluck(:details).map { |details| details['reason'] }.uniq).to eq(['already_imported'])
+      expect(
+        DataImportMapping.where(account: account, source_provider: 'intercom', source_object_type: 'message').distinct.pluck(:data_import_id)
+      ).to eq([data_import.id])
+    end
+
+    it 'reconciles skipped stats when a superseded run is retried', :aggregate_failures do
+      described_class.new(data_import: data_import).perform
+      run_id = 'intercom-run-1'
+      next_run_id = 'intercom-run-2'
+      next_data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+
+      importer = described_class.new(data_import: next_data_import, run_id: run_id)
+      allow(importer).to receive(:skip_existing_message_mapping).and_wrap_original do |method, *args|
+        method.call(*args)
+        part = args[2]
+        next unless part['id'] == 'part_2'
+
+        DataImport.find(next_data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => next_run_id })
+      end
+
+      importer.import_conversations_page
+      expect(next_data_import.reload.stats.dig('messages', 'skipped')).to eq(0)
+
+      retry_importer = described_class.new(data_import: next_data_import, run_id: next_run_id)
+      retry_importer.import_conversations_page
+      retry_importer.finish!
+
+      expect(next_data_import.reload.stats.dig('conversations', 'skipped')).to eq(1)
+      expect(next_data_import.stats.dig('messages', 'skipped')).to eq(3)
+      expect(next_data_import.total_records).to eq(5)
+    end
+
+    it 'keeps skipped contact stats when a query timeout is retried after the item update', :aggregate_failures do
+      described_class.new(data_import: data_import).perform
+      importer = described_class.new(data_import: next_data_import)
+      contact_log_attempts = 0
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:record_already_imported_log).and_wrap_original do |method, **attributes|
+        if attributes[:source_object_type] == 'contact'
+          contact_log_attempts += 1
+          raise ActiveRecord::QueryCanceled, 'statement timeout' if contact_log_attempts == 1
+        end
+
+        method.call(**attributes)
+      end
+
+      importer.import_contacts_page
+
+      contact_item = next_data_import.items.find_by!(source_object_type: 'contact', source_object_id: 'contact_1')
+      expect(contact_log_attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(contact_item).to be_skipped
+      expect(next_data_import.reload.stats.dig('contacts', 'skipped')).to eq(1)
+      expect(next_data_import.import_errors.skip_logs.exists?(data_import_item: contact_item)).to be(true)
     end
 
     it 'recreates messages when existing message mappings point to deleted records', :aggregate_failures do
@@ -429,6 +1048,34 @@ RSpec.describe DataImports::Intercom::Importer do
       expect(next_data_import.import_errors.skip_logs.where(source_object_type: 'message')).to be_empty
       message_mappings = DataImportMapping.where(account: account, source_provider: 'intercom', source_object_type: 'message')
       expect(message_mappings.filter_map(&:chatwoot_record).count).to eq(3)
+      expect(message_mappings.distinct.pluck(:data_import_id)).to eq([next_data_import.id])
+    end
+
+    it 'repairs a missing mapping without recreating the existing message', :aggregate_failures do
+      described_class.new(data_import: data_import).import_conversations_page
+      conversation = account.conversations.find_by!(identifier: 'intercom:conversation_1')
+      message = conversation.messages.find_by!(source_id: 'intercom:conversation:conversation_1:part:part_1')
+      DataImportMapping.find_by!(
+        account: account,
+        source_provider: 'intercom',
+        source_object_type: 'message',
+        source_object_id: 'conversation:conversation_1:part:part_1'
+      ).destroy!
+      importer = described_class.new(data_import: data_import)
+      allow(importer).to receive(:find_mapping).and_call_original
+
+      importer.import_conversations_page
+
+      repaired_mapping = DataImportMapping.find_by!(
+        account: account,
+        source_provider: 'intercom',
+        source_object_type: 'message',
+        source_object_id: 'conversation:conversation_1:part:part_1'
+      )
+      expect(conversation.messages.where(source_id: message.source_id).count).to eq(1)
+      expect(repaired_mapping.chatwoot_record).to eq(message)
+      expect(importer).not_to have_received(:find_mapping).with('message', anything)
+      expect(data_import.reload.stats.dig('messages', 'imported')).to eq(3)
     end
 
     it 'updates conversation activity when a later import adds new messages to the mapped conversation', :aggregate_failures do
@@ -493,7 +1140,11 @@ RSpec.describe DataImports::Intercom::Importer do
     end
 
     it 'repairs the item and imported count on retry', :aggregate_failures do
-      described_class.new(data_import: data_import).import_contacts_page
+      importer = described_class.new(data_import: data_import)
+      expect(importer).to receive(:reconcile_item_stats).with('contact').once.ordered.and_call_original
+      expect(importer).to receive(:update_cursor).with('contacts', nil).once.ordered.and_call_original
+
+      importer.import_contacts_page
 
       item = data_import.items.find_by!(source_object_type: 'contact', source_object_id: 'contact_1')
       expect(item).to be_imported
@@ -741,6 +1392,42 @@ RSpec.describe DataImports::Intercom::Importer do
       expect(data_import.reload.stats.dig('messages', 'skipped')).to eq(1)
     end
 
+    it 'retries skip-log reconciliation after a query timeout', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      attempts = 0
+      allow(importer).to receive(:sleep)
+      allow(importer).to receive(:record_skipped_message_log).and_wrap_original do |method, *args|
+        attempts += 1
+        raise ActiveRecord::QueryCanceled, 'statement timeout' if attempts == 1
+
+        method.call(*args)
+      end
+
+      importer.perform
+
+      expect(attempts).to eq(2)
+      expect(importer).to have_received(:sleep).with(be_between(0.2, 0.5)).once
+      expect(data_import.reload).to be_completed
+      expect(data_import.stats.dig('messages', 'skipped')).to eq(1)
+    end
+
+    it 'isolates a persistent skip-log reconciliation failure to the message', :aggregate_failures do
+      importer = described_class.new(data_import: data_import)
+      allow(importer).to receive(:record_skipped_message_log).and_raise(ActiveRecord::StatementInvalid, 'skip log failed')
+
+      importer.perform
+
+      item = data_import.items.find_by!(source_object_type: 'conversation', source_object_id: 'conversation_1')
+      error = data_import.import_errors.find_by!(
+        source_object_type: 'message',
+        source_object_id: 'conversation:conversation_1:part:blank_part'
+      )
+      expect(item).to be_imported
+      expect(error).to have_attributes(error_code: 'ActiveRecord::StatementInvalid', message: 'skip log failed')
+      expect(data_import.reload).to be_completed_with_errors
+      expect(data_import.stats.dig('errors', 'count')).to eq(1)
+    end
+
     it 'records the skip log again for a later import run', :aggregate_failures do
       described_class.new(data_import: data_import).perform
       next_data_import = create(
@@ -876,6 +1563,29 @@ RSpec.describe DataImports::Intercom::Importer do
       expect(data_import.reload).to be_completed_with_errors
       expect(data_import.stats.dig('errors', 'count')).to eq(1)
     end
+
+    it 'reconciles error stats when a superseded run is retried', :aggregate_failures do
+      run_id = 'intercom-run-1'
+      next_run_id = 'intercom-run-2'
+      data_import.update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => run_id })
+      importer = described_class.new(data_import: data_import, run_id: run_id)
+      allow(importer).to receive(:bulk_write_message_entries).and_wrap_original do |method, *args|
+        method.call(*args).tap do
+          DataImport.find(data_import.id).update!(source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => next_run_id })
+        end
+      end
+
+      importer.import_conversations_page
+      expect(data_import.reload.stats.dig('errors', 'count')).to eq(0)
+
+      retry_importer = described_class.new(data_import: data_import, run_id: next_run_id)
+      retry_importer.import_conversations_page
+      retry_importer.finish!
+
+      expect(data_import.reload).to be_completed_with_errors
+      expect(data_import.stats.dig('errors', 'count')).to eq(1)
+      expect(data_import.total_records).to eq(6)
+    end
   end
 
   context 'when the conversation parts total matches the returned parts' do
@@ -922,6 +1632,8 @@ RSpec.describe DataImports::Intercom::Importer do
   end
 
   context 'when a specific Intercom message part fails to persist' do
+    let(:insert_attempts) { [] }
+
     let(:conversation_payload) do
       super().deep_merge(
         'conversation_parts' => {
@@ -942,7 +1654,10 @@ RSpec.describe DataImports::Intercom::Importer do
 
     before do
       allow(Message).to receive(:insert_all!).and_wrap_original do |method, records, **kwargs|
-        raise ActiveRecord::StatementInvalid, 'bad message' if records.first[:source_id] == 'intercom:conversation:conversation_1:part:bad_part'
+        if records.any? { |record| record[:source_id] == 'intercom:conversation:conversation_1:part:bad_part' }
+          insert_attempts << 'intercom:conversation:conversation_1:part:bad_part'
+          raise ActiveRecord::StatementInvalid, 'bad message'
+        end
 
         method.call(records, **kwargs)
       end
@@ -963,6 +1678,9 @@ RSpec.describe DataImports::Intercom::Importer do
       )
       expect(data_import.reload).to be_completed_with_errors
       expect(data_import.stats.dig('errors', 'count')).to eq(1)
+      expect(insert_attempts.size).to eq(2)
+      expect(data_import.import_errors.where(source_object_type: 'message').count).to eq(1)
+      expect(account.messages.find_by(source_id: 'intercom:conversation:conversation_1:source:source_1')).to be_present
     end
   end
 end

spec/services/data_imports/intercom/message_batch_builder_spec.rb

@@ -0,0 +1,205 @@
+require 'rails_helper'
+
+RSpec.describe DataImports::Intercom::MessageBatchBuilder do
+  let(:account) { create(:account) }
+  let(:data_import) { create(:data_import, :intercom, account: account) }
+  let(:conversation) { create(:conversation, account: account) }
+  let(:source_conversation) do
+    {
+      'id' => 'conversation_1',
+      'created_at' => 1_700_000_000,
+      'source' => {
+        'id' => 'source_1',
+        'part_type' => 'conversation',
+        'body' => '<p>Initial message</p>',
+        'created_at' => 1_700_000_000
+      },
+      'conversation_parts' => {
+        'conversation_parts' => [
+          {
+            'id' => 'part_1',
+            'part_type' => 'comment',
+            'body' => '<p>First reply</p>',
+            'created_at' => 1_700_000_000
+          },
+          {
+            'id' => 'part_2',
+            'part_type' => 'note',
+            'body' => '<p>Internal note</p>',
+            'created_at' => 1_700_000_100
+          }
+        ]
+      }
+    }
+  end
+  let(:builder) do
+    described_class.new(
+      data_import: data_import,
+      conversation: conversation,
+      source_conversation: source_conversation
+    )
+  end
+
+  it 'preserves source order and prefetches mappings and messages once per batch', :aggregate_failures do
+    sql_queries = []
+    subscriber = lambda do |_name, _start, _finish, _id, payload|
+      sql_queries << payload unless payload[:name] == 'SCHEMA'
+    end
+    batch_builder = builder
+
+    batch = ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') { batch_builder.perform }
+
+    expect(batch.entries.map(&:source_id)).to eq(
+      %w[
+        conversation:conversation_1:source:source_1
+        conversation:conversation_1:part:part_1
+        conversation:conversation_1:part:part_2
+      ]
+    )
+    expect(batch.entries.map(&:position)).to eq([0, 1, 2])
+    expect(batch.entries.map(&:classification)).to all(eq(:new_message))
+    expect(sql_queries.count { |query| query[:name] == 'DataImportMapping Load' }).to eq(1)
+    message_queries = sql_queries.select { |query| query[:name] == 'Message Load' }
+    expect(message_queries.size).to eq(1), message_queries.pluck(:sql).join("\n")
+  end
+
+  it 'returns an empty batch without prefetch queries when the conversation has no messages' do
+    source_conversation['source'] = nil
+    source_conversation['conversation_parts']['conversation_parts'] = []
+
+    expect(DataImportMapping).not_to receive(:where)
+    expect(Message).not_to receive(:where)
+
+    expect(builder.perform.entries).to be_empty
+  end
+
+  it 'refreshes classifications while preserving source positions' do
+    batch = builder.perform
+    target_entry = batch.entries.second
+    message = create(
+      :message,
+      account: account,
+      conversation: conversation,
+      inbox: conversation.inbox,
+      source_id: "intercom:#{target_entry.source_id}"
+    )
+    DataImportMapping.create!(
+      account: account,
+      data_import: data_import,
+      source_provider: 'intercom',
+      source_object_type: 'message',
+      source_object_id: target_entry.source_id,
+      chatwoot_record_type: 'Message',
+      chatwoot_record_id: message.id,
+      metadata: {}
+    )
+
+    refreshed_batch = builder.refresh(batch.entries)
+
+    expect(refreshed_batch.entries.map(&:position)).to eq([0, 1, 2])
+    expect(refreshed_batch.entries.second).to have_attributes(classification: :current_import, message: message)
+  end
+
+  it 'classifies a live mapping from the current import as already handled' do
+    message = create(
+      :message,
+      account: account,
+      conversation: conversation,
+      inbox: conversation.inbox,
+      source_id: 'intercom:conversation:conversation_1:part:part_1'
+    )
+    DataImportMapping.create!(
+      account: account,
+      data_import: data_import,
+      source_provider: 'intercom',
+      source_object_type: 'message',
+      source_object_id: 'conversation:conversation_1:part:part_1',
+      chatwoot_record_type: 'Message',
+      chatwoot_record_id: message.id,
+      metadata: {}
+    )
+
+    entry = builder.perform.entries.find { |batch_entry| batch_entry.source_id.end_with?('part:part_1') }
+
+    expect(entry).to have_attributes(classification: :current_import, message: message)
+  end
+
+  it 'classifies a live mapping from a previous import without changing its owner' do
+    previous_import = create(:data_import, :intercom, account: account)
+    message = create(
+      :message,
+      account: account,
+      conversation: conversation,
+      inbox: conversation.inbox,
+      source_id: 'intercom:conversation:conversation_1:part:part_1'
+    )
+    mapping = DataImportMapping.create!(
+      account: account,
+      data_import: previous_import,
+      source_provider: 'intercom',
+      source_object_type: 'message',
+      source_object_id: 'conversation:conversation_1:part:part_1',
+      chatwoot_record_type: 'Message',
+      chatwoot_record_id: message.id,
+      metadata: {}
+    )
+
+    entry = builder.perform.entries.find { |batch_entry| batch_entry.source_id.end_with?('part:part_1') }
+
+    expect(entry).to have_attributes(classification: :previous_import, mapping: mapping, message: message)
+    expect(mapping.reload.data_import).to eq(previous_import)
+  end
+
+  it 'classifies a mapping whose message was deleted as repairable' do
+    mapping = DataImportMapping.create!(
+      account: account,
+      data_import: data_import,
+      source_provider: 'intercom',
+      source_object_type: 'message',
+      source_object_id: 'conversation:conversation_1:part:part_1',
+      chatwoot_record_type: 'Message',
+      chatwoot_record_id: 0,
+      metadata: {}
+    )
+
+    entry = builder.perform.entries.find { |batch_entry| batch_entry.source_id.end_with?('part:part_1') }
+
+    expect(entry).to have_attributes(classification: :repairable_stale_mapping, mapping: mapping, message: nil)
+  end
+
+  it 'classifies an existing conversation message without a mapping for repair' do
+    message = create(
+      :message,
+      account: account,
+      conversation: conversation,
+      inbox: conversation.inbox,
+      source_id: 'intercom:conversation:conversation_1:part:part_1'
+    )
+
+    entry = builder.perform.entries.find { |batch_entry| batch_entry.source_id.end_with?('part:part_1') }
+
+    expect(entry).to have_attributes(classification: :existing_message, mapping: nil, message: message)
+  end
+
+  it 'repairs a skipped mapping when the source part is now an activity' do
+    source_conversation.dig('conversation_parts', 'conversation_parts').first.merge!(
+      'part_type' => 'assignment',
+      'body' => nil,
+      'assigned_to' => { 'name' => 'Support' }
+    )
+    mapping = DataImportMapping.create!(
+      account: account,
+      data_import: data_import,
+      source_provider: 'intercom',
+      source_object_type: 'message',
+      source_object_id: 'conversation:conversation_1:part:part_1',
+      chatwoot_record_type: 'Conversation',
+      chatwoot_record_id: conversation.id,
+      metadata: { skipped: true }
+    )
+
+    entry = builder.perform.entries.find { |batch_entry| batch_entry.source_id.end_with?('part:part_1') }
+
+    expect(entry).to have_attributes(classification: :repairable_stale_mapping, mapping: mapping, message: nil)
+  end
+end

spec/services/data_imports/intercom/retry_service_spec.rb

@@ -0,0 +1,82 @@
+require 'rails_helper'
+
+RSpec.describe DataImports::Intercom::RetryService do
+  let(:account) { create(:account) }
+  let(:data_import) { create(:data_import, :intercom, account: account, status: :processing, started_at: 2.hours.ago) }
+
+  before do
+    account.enable_features!('data_import')
+  end
+
+  it 'prepares a stalled import for another run without clearing progress', :aggregate_failures do
+    original_cursor = { 'contacts' => { 'completed' => true }, 'conversations' => { 'starting_after' => 'cursor-1' } }
+    original_stats = { 'contacts' => { 'imported' => 10 }, 'conversations' => { 'imported' => 5 } }
+    started_at = data_import.started_at
+    error = data_import.import_errors.create!(error_code: 'MessageFailed', message: 'Timed out')
+    data_import.update!(
+      cursor: original_cursor,
+      stats: original_stats,
+      source_metadata: { DataImport::ACTIVE_INTERCOM_IMPORT_RUN_ID_KEY => 'previous-run' },
+      updated_at: 16.minutes.ago
+    )
+
+    result = described_class.new(account: account, data_import: data_import).perform
+
+    expect(result).to eq(:enqueue)
+    expect(data_import.reload).to be_pending
+    expect(data_import.started_at).to eq(started_at)
+    expect(data_import.cursor).to eq(original_cursor)
+    expect(data_import.stats).to eq(original_stats)
+    expect(data_import.import_errors).to contain_exactly(error)
+    expect(data_import.active_intercom_import_run_id).not_to eq('previous-run')
+  end
+
+  it 'does not retry an import that is still receiving updates' do
+    result = described_class.new(account: account, data_import: data_import).perform
+
+    expect(result).to eq(:not_stalled)
+    expect(data_import.reload).to be_processing
+  end
+
+  it 'rechecks the import state after acquiring its row lock' do
+    data_import.update!(updated_at: 16.minutes.ago)
+    allow(data_import).to receive(:with_lock).and_wrap_original do |method, *args, &block|
+      data_import.update!(status: :completed, completed_at: Time.current)
+      method.call(*args, &block)
+    end
+
+    result = described_class.new(account: account, data_import: data_import).perform
+
+    expect(result).to eq(:not_stalled)
+    expect(data_import.reload).to be_completed
+  end
+
+  it 'does not retry while another Intercom import is active' do
+    data_import.update!(updated_at: 16.minutes.ago)
+    create(:data_import, :intercom, account: account, status: :processing)
+
+    result = described_class.new(account: account, data_import: data_import).perform
+
+    expect(result).to eq(:active_import_exists)
+    expect(data_import.reload).to be_processing
+  end
+
+  it 'allows an active legacy import to continue alongside the retry' do
+    data_import.update!(updated_at: 16.minutes.ago)
+    create(:data_import, account: account, status: :processing)
+
+    result = described_class.new(account: account, data_import: data_import).perform
+
+    expect(result).to eq(:enqueue)
+    expect(data_import.reload).to be_pending
+  end
+
+  it 'does not retry when the stored access key is unavailable' do
+    data_import.update!(access_token: nil, updated_at: 16.minutes.ago)
+
+    result = described_class.new(account: account, data_import: data_import).perform
+
+    expect(result).to eq(:access_token_missing)
+    expect(data_import.reload).to be_processing
+  end
+end