try {
            searchEngineClient.deleteByQuery(fessConfig.getIndexDocumentUpdateIndex(), queryBuilder);

        } catch (final Exception e) {
            logger.error("Could not delete expired documents: {}", queryBuilder, e);
            resultBuf.append(e.getMessage()).append("\n");
        }

        return resultBuf.toString();
    }

---
title: "Go, Backwards Compatibility, and GODEBUG"
layout: article
---

<!--
This document is kept in the Go repo, not x/website,
because it documents the full list of known GODEBUG settings,
which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.

                        <OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/">
                          <ShortName>Fess</ShortName>
                          <Description>Full Text Search for Your Documents.</Description>
                          <Tags>Full Text Search</Tags>
                          <Contact>******@****.***</Contact>
                          <SearchForm>http://localhost:8080/fess/</SearchForm>

labels.dict_stopwords_file 	=	Fichier des Stopwords
labels.boost_document_rule_configuration	=	Doc Boost
labels.boost_document_rule_title_details	=	Doc Boost
labels.boost_document_rule_list_url_expr	=	Condition
labels.boost_document_rule_url_expr	=	Condition
labels.boost_document_rule_boost_expr	=	Boost Expr
labels.boost_document_rule_sort_order	=	Ordre de tri
labels.access_token_configuration	=	Access Token

                final String id = crawlingInfoHelper.generateId(dataMap);

                if (logger.isDebugEnabled()) {
                    logger.debug("Searching indexed document: {}", id);
                }
                final Map<String, Object> document = indexingHelper.getDocument(searchEngineClient, id,
                        new String[] { fessConfig.getIndexFieldId(), fessConfig.getIndexFieldLastModified(),

    @Execute
    public JsonResponse<ApiResult> docs(final SearchBody body) {
        validateApi(body, messages -> {});

        if (StringUtil.isBlank(body.q)) {
            // query matches on all documents.
            body.q = Constants.MATCHES_ALL_QUERY;
        }

        final SearchRenderData renderData = new SearchRenderData();
        body.initialize();
        try {

!!! note
    Notice that as we communicate with the database using `await`, the *path operation function* is declared with `async`.

### Notice the `response_model=List[Note]`

It uses `typing.List`.

That documents (and validates, serializes, filters) the output data, as a `list` of `Note`s.

## Create notes

Create the *path operation function* to create notes:

```Python hl_lines="61-65"

        final SystemHelper systemHelper = ComponentUtil.getSystemHelper();
        final long execTime = systemHelper.getCurrentTimeAsLong();
        if (logger.isDebugEnabled()) {
            logger.debug("Sending {} documents to a server.", docList.size());
        }
        try {
            if (fessConfig.isThumbnailCrawlerEnabled()) {
                final ThumbnailManager thumbnailManager = ComponentUtil.getThumbnailManager();

Fess also contains a Crawler, which can crawl documents on a [web server](https://fess.codelibs.org/14.12/admin/webconfig-guide.html), [file system](https://fess.codelibs.org/14.12/admin/fileconfig-guide.html), or [Data Store](https://fess.codelibs.org/14.12/admin/dataconfig-guide.html) (such as a CSV...

    }

    protected HtmlResponse doSearch(final ListForm form) {
        validate(form, messages -> {}, this::asListHtml);

        if (StringUtil.isBlank(form.q)) {
            // query matches on all documents.
            form.q = Constants.MATCHES_ALL_QUERY;
        }
        final WebRenderData renderData = new WebRenderData();
        form.initialize();