diff --git a/tsdb/addsymbol.go b/tsdb/addsymbol.go
new file mode 100644
index 0000000000..e6046c5ed1
--- /dev/null
+++ b/tsdb/addsymbol.go
@@ -0,0 +1,10 @@
+//go:build !stringlabels
+
+// Split out function which needs to be coded differently for stringlabels case.
+
+package tsdb
+
+func (sw *symbolsBatcher) addSymbol(sym string) error {
+	sw.buffer[sym] = struct{}{}
+	return sw.flushSymbols(false)
+}
diff --git a/tsdb/addsymbol_stringlabels.go b/tsdb/addsymbol_stringlabels.go
new file mode 100644
index 0000000000..86f19c847f
--- /dev/null
+++ b/tsdb/addsymbol_stringlabels.go
@@ -0,0 +1,15 @@
+//go:build stringlabels
+
+// Split out function which needs to be coded differently for stringlabels case.
+
+package tsdb
+
+import "strings"
+
+func (sw *symbolsBatcher) addSymbol(sym string) error {
+	if _, found := sw.buffer[sym]; !found {
+		sym = strings.Clone(sym) // So we don't retain reference to the entire labels block.
+		sw.buffer[sym] = struct{}{}
+	}
+	return sw.flushSymbols(false)
+}
diff --git a/tsdb/symbols_batch.go b/tsdb/symbols_batch.go
index 13fe84f907..4ecc66bf02 100644
--- a/tsdb/symbols_batch.go
+++ b/tsdb/symbols_batch.go
@@ -145,11 +145,6 @@ func newSymbolsBatcher(limit int, dir string, flushers *symbolFlushers) *symbols
 	}
 }
 
-func (sw *symbolsBatcher) addSymbol(sym string) error {
-	sw.buffer[sym] = struct{}{}
-	return sw.flushSymbols(false)
-}
-
 func (sw *symbolsBatcher) flushSymbols(force bool) error {
 	if !force && len(sw.buffer) < sw.limit {
 		return nil