Add geo_primary_replication_events to usage data

doc/development/telemetry/usage_ping.md

@@ -456,7 +456,8 @@ On GitLab.com, we have DangerBot setup to monitor Telemetry related files and Da
 | `dependency_list_usages_total`                          | `counts`                           |             |                                                   |
 | `epics`                                                 | `counts`                           |             |                                                   |
 | `feature_flags`                                         | `counts`                           |             |                                                   |
-| `geo_nodes`                                             | `counts`                           |             |                                                   |
+| `geo_nodes`                                             | `counts`                           | `geo`       | Number of sites in a Geo deployment               |
+| `geo_event_log_max_id`                                  | `counts`                           | `geo`       | Number of replication events on a Geo primary     |
 | `incident_issues`                                       | `counts`                           | `monitor`   | Issues created by the alert bot                   |
 | `alert_bot_incident_issues`                             | `counts`                           | `monitor`   | Issues created by the alert bot                   |
 | `incident_labeled_issues`                               | `counts`                           | `monitor`   | Issues with the incident label                    |

ee/changelogs/unreleased/nhxnguyen-geo-usage-ping-replication-events.yml

+---
+title: Add geo_primary_replication_events to usage data
+merge_request: 33424
+author:
+type: other

ee/lib/ee/gitlab/usage_data.rb

@@ -164,6 +164,7 @@ module EE
                 epics: count(::Epic),
                 feature_flags: count(Operations::FeatureFlag),
                 geo_nodes: count(::GeoNode),
+                geo_event_log_max_id: alt_usage_data { Geo::EventLog.maximum(:id) || 0 },
                 ldap_group_links: count(::LdapGroupLink),
                 issues_with_health_status: count(::Issue.with_health_status),
                 ldap_keys: count(::LDAPKey),

ee/spec/lib/ee/gitlab/usage_data_spec.rb

@@ -91,6 +91,7 @@ RSpec.describe Gitlab::UsageData do
         epics_deepest_relationship_level
         feature_flags
         geo_nodes
+        geo_event_log_max_id
         issues_with_health_status
         ldap_group_links
         ldap_keys