Add serializing groups external cache to the next Gerrit news
Change-Id: I3efe20a71e65fb9394807efe23f134486bf287a8
diff --git a/_posts/2020-05-29-gerrit-news-apr-may-2020.md b/_posts/2020-05-29-gerrit-news-apr-may-2020.md
index 8ea9a4a..40d423e 100644
--- a/_posts/2020-05-29-gerrit-news-apr-may-2020.md
+++ b/_posts/2020-05-29-gerrit-news-apr-may-2020.md
@@ -24,6 +24,21 @@
not possible to cherry-pick a topic that has multiple changes in the
same repository and branch.
+## Serializing the External Groups Cache
+
+Gerrit can be linked to external user directories like LDAP,
+providing Gerrit with external users and groups. External groups can
+be added to Gerrit to restrict access to refs and repos and are
+mainly used for permissions evaluation.
+
+We implemented a significant performance improvement by serializing
+the external groups in-memory cache for faster lookups. We used the
+common serialization infrastructure used by other caches. This has an
+impact on Gerrit setups that require frequent server restarts, i.e.
+for warming up caches. For Google hosted Gerrit sites, the cache
+loading time for all lookup requests was reduced from a few hundreds
+of minutes to less than 3 minutes per day.
+
## Comments tab moved
We have renamed the "Comment Threads" tab to "Comments" and moved it
