From 2f5fb235b28a7c90fe8edbd26f56f50029030d8f Mon Sep 17 00:00:00 2001
From: Joe <1060287354@qq.com>
Date: Sat, 4 Jul 2020 09:27:18 +0800
Subject: [PATCH] optimize isExistTable function  (#3236)

* Update EmbeddedStoragePersistServiceImpl.java

If the table data volume is large, count (*) will be particularly slow

* Update ExternalStoragePersistServiceImpl.java

If the table data volume is large, count (*) will be particularly slow

* Update ExternalStoragePersistServiceImpl.java

* Update EmbeddedStoragePersistServiceImpl.java
---
 .../repository/embedded/EmbeddedStoragePersistServiceImpl.java  | 2 +-
 .../repository/extrnal/ExternalStoragePersistServiceImpl.java   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/config/src/main/java/com/alibaba/nacos/config/server/service/repository/embedded/EmbeddedStoragePersistServiceImpl.java b/config/src/main/java/com/alibaba/nacos/config/server/service/repository/embedded/EmbeddedStoragePersistServiceImpl.java
index 548fe61a5..2e62020da 100755
--- a/config/src/main/java/com/alibaba/nacos/config/server/service/repository/embedded/EmbeddedStoragePersistServiceImpl.java
+++ b/config/src/main/java/com/alibaba/nacos/config/server/service/repository/embedded/EmbeddedStoragePersistServiceImpl.java
@@ -2113,7 +2113,7 @@ public class EmbeddedStoragePersistServiceImpl implements PersistService {
     }
     
     public boolean isExistTable(String tableName) {
-        String sql = "SELECT COUNT(*) FROM " + tableName;
+        String sql = String.format("select 1 from %s limit 1", tableName);
         try {
             databaseOperate.queryOne(sql, Integer.class);
             return true;
diff --git a/config/src/main/java/com/alibaba/nacos/config/server/service/repository/extrnal/ExternalStoragePersistServiceImpl.java b/config/src/main/java/com/alibaba/nacos/config/server/service/repository/extrnal/ExternalStoragePersistServiceImpl.java
index a5ee6f166..bbdacd3e0 100644
--- a/config/src/main/java/com/alibaba/nacos/config/server/service/repository/extrnal/ExternalStoragePersistServiceImpl.java
+++ b/config/src/main/java/com/alibaba/nacos/config/server/service/repository/extrnal/ExternalStoragePersistServiceImpl.java
@@ -3147,7 +3147,7 @@ public class ExternalStoragePersistServiceImpl implements PersistService {
 	}
 
 	public boolean isExistTable(String tableName) {
-		String sql = "SELECT COUNT(*) FROM " + tableName;
+		String sql = String.format("select 1 from %s limit 1", tableName);
 		try {
 			jt.queryForObject(sql, Integer.class);
 			return true;