Add a cluster transaction metric (lost subordinates of transactions) (#645)

Author: Simran-B

site/content/3.12/release-notes/version-3.12/api-changes-in-3-12.md

@@ -538,6 +538,15 @@ The following metrics have been added for observability:
 - `arangodb_scheduler_low_prio_dequeue_hist`
 - `arangodb_scheduler_maintenance_prio_dequeue_hist`
 
+---
+
+<small>Introduced in: v3.12.4</small>
+
+The following metric about partially committed or aborted transactions on
+DB-Servers in a cluster has been added:
+
+- `arangodb_vocbase_transactions_lost_subordinates_total`
+
 #### Stream Transactions API
 
 <small>Introduced in: v3.12.1</small>

site/content/3.12/release-notes/version-3.12/whats-new-in-3-12.md

@@ -1868,6 +1868,17 @@ Furthermore, the [HTTP API](../../develop/http-api/monitoring/logs.md#get-the-se
 has been extended to let you query and set the log levels for individual outputs
 at runtime.
 
+### Lost subordinate transactions metric
+
+<small>Introduced in: v3.12.4</small>
+
+The following metric about partially committed or aborted transactions on
+DB-Servers in a cluster has been added:
+
+| Label | Description |
+|:------|:------------|
+| `arangodb_vocbase_transactions_lost_subordinates_total` | Counts the number of lost subordinate transactions on database servers. |
+
 ## Client tools
 
 ### Protocol aliases for endpoints

site/content/3.13/release-notes/version-3.12/api-changes-in-3-12.md

@@ -538,6 +538,15 @@ The following metrics have been added for observability:
 - `arangodb_scheduler_low_prio_dequeue_hist`
 - `arangodb_scheduler_maintenance_prio_dequeue_hist`
 
+---
+
+<small>Introduced in: v3.12.4</small>
+
+The following metric about partially committed or aborted transactions on
+DB-Servers in a cluster has been added:
+
+- `arangodb_vocbase_transactions_lost_subordinates_total`
+
 #### Stream Transactions API
 
 <small>Introduced in: v3.12.1</small>

site/content/3.13/release-notes/version-3.12/whats-new-in-3-12.md

@@ -1868,6 +1868,17 @@ Furthermore, the [HTTP API](../../develop/http-api/monitoring/logs.md#get-the-se
 has been extended to let you query and set the log levels for individual outputs
 at runtime.
 
+### Lost subordinate transactions metric
+
+<small>Introduced in: v3.12.4</small>
+
+The following metric about partially committed or aborted transactions on
+DB-Servers in a cluster has been added:
+
+| Label | Description |
+|:------|:------------|
+| `arangodb_vocbase_transactions_lost_subordinates_total` | Counts the number of lost subordinate transactions on database servers. |
+
 ## Client tools
 
 ### Protocol aliases for endpoints