} catch (final InterruptedException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Executor shutdown interrupted", e);
            }
        } finally {
            executor.shutdownNow();
        }

        synchronized (indexUpdateCallback) {
            if (!deleteUrlList.isEmpty()) {
                deleteDocuments();
            }
        }
        indexUpdateCallback.commit();

                if (logger.isDebugEnabled()) {
                    logger.debug("Executor shutdown interrupted", e);
                }
            } finally {
                executorService.shutdownNow();
            }
        }
    }

    /**
     * Performs a search operation using rank fusion across available searchers.
     * If only one searcher is available, uses the main searcher. Otherwise, performs

      propagateIfInstanceOf(e.getCause(), CancellationException.class);
      throw new AssertionError("Unexpected exception", e);
    } finally {
      executor.shutdownNow();
      // TODO(cpovirk): assertTrue(awaitTerminationUninterruptibly(executor, 10, SECONDS));
    }
  }

  /**

      propagateIfInstanceOf(e.getCause(), CancellationException.class);
      throw new AssertionError("Unexpected exception", e);
    } finally {
      executor.shutdownNow();
      // TODO(cpovirk): assertTrue(awaitTerminationUninterruptibly(executor, 10, SECONDS));
    }
  }

  /**