From 52fd11bb6cf3914206a2e1c112b3dccffa375b1f Mon Sep 17 00:00:00 2001
From: Tom Guinther <tguinther@gfxlabs.io>
Date: Thu, 29 Aug 2024 12:48:29 -0400
Subject: [PATCH] if measure lag is null or 0 fallback to query latency rename
things, add query_threshold
---
.../pool/critics/replication/critic.go | 21 ++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/lib/gat/handlers/pool/critics/replication/critic.go b/lib/gat/handlers/pool/critics/replication/critic.go
index 4b6fd58e..3484cec1 100644
--- a/lib/gat/handlers/pool/critics/replication/critic.go
+++ b/lib/gat/handlers/pool/critics/replication/critic.go
@@ -13,9 +13,20 @@ func init() {
caddy.RegisterModule((*Critic)(nil))
}
+// Critic describes a replication critic which measures replication lag,
+// with a fallback to query latency when there is no *measurable* lag
type Critic struct {
- Threshold caddy.Duration `json:"threshold"`
- Validity caddy.Duration `json:"validity"`
+ QueryThreshold caddy.Duration `json:"query_threshold"`
+ ReplicationThreshold caddy.Duration `json:"replication_threshold"`
+ Validity caddy.Duration `json:"validity"`
+}
+
+func NewCritic() *Critic {
+ return &Critic{
+ QueryThreshold: caddy.Duration(time.Millisecond * 300),
+ ReplicationThreshold: caddy.Duration(time.Second * 3),
+ Validity: caddy.Duration(time.Minute * 5),
+ }
}
func (T *Critic) CaddyModule() caddy.ModuleInfo {
@@ -44,11 +55,11 @@ func (T *Critic) Taste(ctx context.Context, conn *fed.Conn) (int, time.Duration,
penalty := 0
- if result.Lag != nil {
- penalty = int(*result.Lag / time.Duration(T.Threshold).Seconds())
+ if (result.Lag != nil) && (*result.Lag > 0) {
+ penalty = int(*result.Lag / time.Duration(T.ReplicationThreshold).Seconds())
} else {
dur := time.Since(start)
- penalty = int(dur / time.Duration(T.Threshold))
+ penalty = int(dur / time.Duration(T.QueryThreshold))
}
return penalty, time.Duration(T.Validity), nil
--
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