From 93e299305cd302a2a1d77a79ec3bad664a05f099 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Farkas?= <gabor.farkas@gmail.com>
Date: Sat, 21 May 2022 16:39:21 +0200
Subject: [PATCH] loki: backend-mode: apply default max-lines if not set in the
 UI (#48859)

---
 public/app/plugins/datasource/loki/datasource.ts | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/public/app/plugins/datasource/loki/datasource.ts b/public/app/plugins/datasource/loki/datasource.ts
index 0c846361316..ded5e3619dc 100644
--- a/public/app/plugins/datasource/loki/datasource.ts
+++ b/public/app/plugins/datasource/loki/datasource.ts
@@ -173,10 +173,13 @@ export class LokiDatasource
     };
 
     if (this.useBackendMode) {
-      // we "fix" the loki queries to have `.queryType` and not have `.instant` and `.range`
+      const queries = request.targets
+        .map(getNormalizedLokiQuery) // "fix" the `.queryType` prop
+        .map((q) => ({ ...q, maxLines: q.maxLines || this.maxLines })); // set maxLines if not set
+
       const fixedRequest = {
         ...request,
-        targets: request.targets.map(getNormalizedLokiQuery),
+        targets: queries,
       };
 
       const streamQueries = fixedRequest.targets.filter((q) => q.queryType === LokiQueryType.Stream);