ci: Test that pool reuses TiDB connections

azure-pipelines.yml

@@ -152,6 +152,28 @@ jobs:
           DATABASE_URL: mysql://root:password@localhost/mysql
         displayName: Run tests
 
+  - job: "TestTiDB"
+    pool:
+      vmImage: "ubuntu-latest"
+    strategy:
+      matrix:
+        v5.3.0:
+          DB_VERSION: "v5.3.0"
+        v5.0.6:
+          DB_VERSION: "v5.0.6"
+    steps:
+      - bash: |
+          curl --proto '=https' --tlsv1.2 -sSf https://tiup-mirrors.pingcap.com/install.sh | sh
+          source ~/.profile
+          tiup playground $(DB_VERSION) --db 1 --pd 1 --kv 1 &
+          while ! nc -W 1 localhost 4000 | grep -q -P '.+'; do sleep 1; done
+        displayName: Install and run TiDB
+      - bash: cargo test should_reuse_connections -- --nocapture
+        displayName: Run tests
+        env:
+          RUST_BACKTRACE: 1
+          DATABASE_URL: mysql://root@127.0.0.1:4000/mysql
+
   - job: "TestMySql"
     pool:
       vmImage: "ubuntu-latest"

src/conn/mod.rs

@@ -201,6 +201,11 @@ impl ConnInner {
 pub struct Conn(Box<ConnInner>);
 
 impl Conn {
+    /// Returns version number reported by the server.
+    pub fn server_version(&self) -> (u16, u16, u16) {
+        self.0.server_version.unwrap()
+    }
+
     /// Returns connection identifier.
     pub fn connection_id(&self) -> u32 {
         self.0.connection_id

src/conn/pool.rs

@@ -622,6 +622,24 @@ mod test {
             a.add();
         }
 
+        #[test]
+        fn should_reuse_connections() -> crate::Result<()> {
+            let pool = Pool::new_manual(1, 1, get_opts())?;
+            let mut conn = pool.get_conn()?;
+
+            let server_version = conn.server_version();
+            let connection_id = conn.connection_id();
+
+            for _ in 0..16 {
+                drop(conn);
+                conn = pool.get_conn()?;
+                println!("CONN connection_id={}", conn.connection_id());
+                assert!(conn.connection_id() == connection_id || server_version < (5, 7, 2));
+            }
+
+            Ok(())
+        }
+
         #[test]
         fn should_start_transaction_on_PooledConn() {
             let pool = Pool::new(get_opts()).unwrap();