# Wetech Cloud total TiKV node memory alert

Apply this topic only when the typed ticket has a non-empty `orgId` and the
question contains the exact Wetech-managed `TotalTiKVMemoryUsageTooHigh` name
or total-TiKV-cluster alert text. That alert identity is sufficient when Jira
does not provide Account Alias. Never apply it to Wetech OP, an APID ticket, or
an ordinary memory question without an alert identity.

`TotalTiKVMemoryUsageTooHigh` evaluates the cluster-wide average host-memory
utilization of TiKV nodes:

```promql
1 - avg by (tidb_cluster_id) (
  (
    node_memory_MemFree_bytes{component="tikv"} +
    node_memory_Buffers_bytes{component="tikv"} +
    node_memory_Cached_bytes{component="tikv"}
  ) / node_memory_MemTotal_bytes{component="tikv"}
)
```

- Compare the alert with the same cluster-wide average calculation. One TiKV
  node crossing the threshold does not prove that this total alert fired.
- The threshold and duration in the actual alert configuration are
  authoritative. The runbooks template currently shows `> 0.7` for 10 minutes.
- TiKV process RSS divided by the advertised node size is a different metric
  and cannot reproduce or negate this alert.
- The rule explains why the alert fired. It does not establish which allocator,
  workload, cache, backlog, or leak caused the host-memory utilization.

Source: `tidbcloud/runbooks/rules/customer/resources.rules.yaml`, alert
`TotalTiKVMemoryUsageTooHigh`, observed at runbooks commit `b2c38f9c` on
2026-08-20.