From 44fab9eab54718b2fa8b3743095d0fa92a833852 Mon Sep 17 00:00:00 2001
From: Massaki Archambault <badjware@massaki.ca>
Date: Fri, 24 Dec 2021 15:46:04 -0500
Subject: [PATCH] reduce lock contention

---
 exporter.go | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/exporter.go b/exporter.go
index 37dbfc5..ef1bc6a 100644
--- a/exporter.go
+++ b/exporter.go
@@ -78,6 +78,7 @@ type AccountTx struct {
 // Hotspot represents a hotspot
 type Hotspot struct {
 	Address      string
+	UpdateLock   sync.Mutex
 	LastUpdate   time.Time
 	RewardsTotal map[string]int
 }
@@ -667,6 +668,11 @@ func (e *Exporter) collectHotspotMetrics(wg *sync.WaitGroup, ch chan<- prometheu
 			continue
 		}
 
+		// create the hotspot object if it doesn't exist
+		if _, ok := account.Hotspots[hotspotData.Address]; !ok {
+			account.Hotspots[hotspotData.Address] = NewHotspot(hotspotData.Address)
+		}
+
 		// collect hotspot metric requiring extra queries in a new routine
 		wg.Add(4)
 		go e.collectHotspotBlocksDeltaMetrics(wg, ch, account, hotspotData)
@@ -791,16 +797,15 @@ func (e *Exporter) collectHotspotRewardsMetrics(wg *sync.WaitGroup, ch chan<- pr
 		"rewards_v2",
 	}
 
-	// TODO: optimize locks
-	account.UpdateLock.Lock()
-	defer account.UpdateLock.Unlock()
-
 	hotspot, ok := account.Hotspots[hotspotData.Address]
 	if !ok {
-		hotspot = NewHotspot(hotspotData.Address)
-		account.Hotspots[hotspotData.Address] = hotspot
+		log.Fatalf("BUG: attempted to access hotspot %v before it was created", hotspotData.Address)
+		return
 	}
 
+	hotspot.UpdateLock.Lock()
+	defer hotspot.UpdateLock.Unlock()
+
 	// We want to keep in memory the timestamp of the last activity we
 	// received from the api. We cannot do something naive like [lastscrape, now]
 	// because the api can take a few seconds to sync with the chain and