diff --git a/changelogs/head.asciidoc b/changelogs/head.asciidoc
index 0a98131034d..4787d500741 100644
--- a/changelogs/head.asciidoc
+++ b/changelogs/head.asciidoc
@@ -13,6 +13,7 @@ https://github.com/elastic/apm-server/compare/8.1\...main[View commits]
 [float]
 ==== Bug fixes
 - Do not overwrite `service version` if no transaction/error/... specific `service.name` is given {pull}7281[7281]
+- modelindexer: Fix indexing performance regression due to locking bug {pull}7649[7649]
 
 [float]
 ==== Intake API Changes
diff --git a/model/modelindexer/indexer.go b/model/modelindexer/indexer.go
index 4fb0ae70231..a0b12b88bdf 100644
--- a/model/modelindexer/indexer.go
+++ b/model/modelindexer/indexer.go
@@ -334,9 +334,9 @@ func (i *Indexer) flushActive(ctx context.Context) error {
 	}()
 
 	i.activeMu.Lock()
-	defer i.activeMu.Unlock()
 	bulkIndexer := i.active
 	i.active = nil
+	i.activeMu.Unlock()
 	err := i.flush(ctx, bulkIndexer)
 	bulkIndexer.Reset()
 	i.available <- bulkIndexer