Break down cache expiry reasons in grafana (#10880)

A follow-up to #10829

2 files changed, 3 insertions, 2 deletions

diff --git a/changelog.d/10880.misc b/changelog.d/10880.misc
new file mode 100644

index 0000000000..5f58d6198c
--- /dev/null
+++ b/changelog.d/10880.misc
@@ -0,0 +1 @@
+Break down Grafana's cache expiry time series based on reason for eviction---see #10829.
\ No newline at end of file
diff --git a/contrib/grafana/synapse.json b/contrib/grafana/synapse.json

index ed1e8ba7f8..2c839c30d0 100644
--- a/contrib/grafana/synapse.json
+++ b/contrib/grafana/synapse.json
@@ -6785,7 +6785,7 @@
               "expr": "rate(synapse_util_caches_cache:evicted_size{instance=\"$instance\",job=~\"$job\",index=~\"$index\"}[$bucket_size])",
               "format": "time_series",
               "intervalFactor": 1,
-              "legendFormat": "{{name}} {{job}}-{{index}}",
+              "legendFormat": "{{name}} ({{reason}}) {{job}}-{{index}}",
               "refId": "A"
             }
           ],
@@ -10888,5 +10888,5 @@
   "timezone": "",
   "title": "Synapse",
   "uid": "000000012",
-  "version": 99
+  "version": 100
 }
\ No newline at end of file