From 7f310cec9c9a4f3ce154211e8d982ad30f8e173e Mon Sep 17 00:00:00 2001
From: minghong <englefly@gmail.com>
Date: Fri, 22 Dec 2023 14:45:33 +0800
Subject: [PATCH] [opt](sessionVar)show changed sessoin var first #28840
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“show variables” command list changed vars before not changed vars,
---
 .../java/org/apache/doris/qe/VariableMgr.java | 25 ++++++++++++++-----
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java b/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
index 170c86e47e..7b797ea84a 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/VariableMgr.java
@@ -691,7 +691,8 @@ public class VariableMgr {
 
     // Dump all fields. Used for `show variables`
     public static List<List<String>> dump(SetType type, SessionVariable sessionVar, PatternMatcher matcher) {
-        List<List<String>> rows = Lists.newArrayList();
+        List<List<String>> changedRows = Lists.newArrayList();
+        List<List<String>> defaultRows = Lists.newArrayList();
         // Hold the read lock when session dump, because this option need to access global variable.
         rlock.lock();
         try {
@@ -732,23 +733,35 @@ public class VariableMgr {
                 } else {
                     row.add(varContext.defaultValue);
                 }
-                row.add(row.get(1).equals(row.get(2)) ? "0" : "1");
-
-                rows.add(row);
+                if (row.get(1).equals(row.get(2))) {
+                    row.add("0");
+                    defaultRows.add(row);
+                } else {
+                    row.add("1");
+                    changedRows.add(row);
+                }
             }
         } finally {
             rlock.unlock();
         }
 
         // Sort all variables by variable name.
-        Collections.sort(rows, new Comparator<List<String>>() {
+        Collections.sort(changedRows, new Comparator<List<String>>() {
             @Override
             public int compare(List<String> o1, List<String> o2) {
                 return o1.get(0).compareTo(o2.get(0));
             }
         });
 
-        return rows;
+        Collections.sort(defaultRows, new Comparator<List<String>>() {
+            @Override
+            public int compare(List<String> o1, List<String> o2) {
+                return o1.get(0).compareTo(o2.get(0));
+            }
+        });
+
+        changedRows.addAll(defaultRows);
+        return changedRows;
     }
 
     @Retention(RetentionPolicy.RUNTIME)