From dbdb78d38abf81da00aea801680da680a768f622 Mon Sep 17 00:00:00 2001
From: JianBo He <heeejianbo@gmail.com>
Date: Thu, 24 Nov 2022 15:24:55 +0800
Subject: [PATCH] chore: clarify the case when count returns zero

---
 apps/emqx_dashboard/src/emqx_dashboard_swagger.erl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/apps/emqx_dashboard/src/emqx_dashboard_swagger.erl b/apps/emqx_dashboard/src/emqx_dashboard_swagger.erl
index 5ea2e0773..5af1aee89 100644
--- a/apps/emqx_dashboard/src/emqx_dashboard_swagger.erl
+++ b/apps/emqx_dashboard/src/emqx_dashboard_swagger.erl
@@ -138,7 +138,12 @@ fields(limit) ->
     Meta = #{in => query, desc => Desc, default => ?DEFAULT_ROW, example => 50},
     [{limit, hoconsc:mk(range(1, ?MAX_ROW_LIMIT), Meta)}];
 fields(count) ->
-    Meta = #{desc => <<"Results count.">>, required => true},
+    Desc = <<
+        "Total number of records counted.<br/>"
+        "Note: this field is <code>0</code> when the queryed table is empty, "
+        "or if the query can not be optimized and requires a full table scan."
+    >>,
+    Meta = #{desc => Desc, required => true},
     [{count, hoconsc:mk(non_neg_integer(), Meta)}];
 fields(meta) ->
     fields(page) ++ fields(limit) ++ fields(count).