Add local markdown versionlocal-markdown-version

Cached markdown version is composed both from global and local
markdown version. This allows admins to bump version locally when
needed (e.g. when external URL is changed).

1 files changed, 16 insertions, 0 deletions

diff --git a/doc/administration/invalidate_markdown_cache.md b/doc/administration/invalidate_markdown_cache.md
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+# Invalidate Markdown Cache
+
+For performance reasons, GitLab caches the HTML version of markdown text
+(e.g. issue and merge request descriptions, comments). It's possible
+that these cached versions become outdated, for example
+when the `external_url` configuration option is changed - causing links
+in the cached text to refer to the old URL.
+
+To avoid this problem, the administrator can invalidate the existing cache by
+increasing the `local_markdown_version` setting in application settings.  This can
+be done by [changing the application settings through
+the API](../api/settings.md#change-application-settings):
+
+```bash
+curl --request PUT --header "PRIVATE-TOKEN: <your_access_token>" https://gitlab.example.com/api/v4/application/settings?local_markdown_version=<increased_number>
+```