sadpandajoe commented on code in PR #43523: URL: https://github.com/apache/superset/pull/43523#discussion_r4022440479
########## docs/admin_docs/configuration/cache.mdx: ########## @@ -326,6 +326,32 @@ Then on configuration: WEBDRIVER_AUTH_FUNC = auth_driver ``` +### Refreshing successfully-rendered thumbnails + +Once a thumbnail renders successfully it is cached with no expiry, so on cache backends without +TTL eviction (for example S3) a stale — or valid-but-blank — capture can be served indefinitely to +callers that do not pass `force=true`. `THUMBNAIL_UPDATED_CACHE_TTL` bounds how long a +successfully-rendered thumbnail is served before it is recomputed: + +```python +from datetime import timedelta + +# Recompute a successfully-rendered thumbnail once it is older than 7 days (the default, +# matching THUMBNAIL_CACHE_CONFIG's CACHE_DEFAULT_TIMEOUT). +THUMBNAIL_UPDATED_CACHE_TTL = int(timedelta(days=7).total_seconds()) +``` + +- **Opt out:** set `THUMBNAIL_UPDATED_CACHE_TTL = 0` (or `None`) to keep serving a rendered Review Comment: Setting this to `0` doesn't keep thumbnails indefinitely on TTL-capable backends: cache writes still use `THUMBNAIL_CACHE_CONFIG.CACHE_DEFAULT_TIMEOUT` (seven days by default), so this only disables the new age check and restores backend-defined retention. Could the opt-out text say that instead of promising serve-forever behavior? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
