backup: change file name with local timestamp (tikv#8707)

Signed-off-by: luancheng <luancheng@pingcap.com>

components/backup/src/endpoint.rs

@@ -5,6 +5,7 @@ use std::f64::INFINITY;
 use std::fmt;
 use std::sync::atomic::*;
 use std::sync::*;
+use std::time::{SystemTime, UNIX_EPOCH};
 use std::{borrow::Cow, time::*};
 
 use concurrency_manager::ConcurrencyManager;
@@ -871,16 +872,23 @@ fn get_max_start_key(start_key: Option<&Key>, region: &Region) -> Option<Key> {
     }
 }
 
-/// Construct an backup file name based on the given store id and region.
-/// A name consists with three parts: store id, region_id and a epoch version.
+/// Construct an backup file name based on the given store id, region, range start key and local unix timestamp.
+/// A name consists with five parts: store id, region_id, a epoch version, the hash of range start key and timestamp.
+/// range start key is used to keep the unique file name for file, to handle different tables exists on the same region.
+/// local unix timestamp is used to keep the unique file name for file, to handle receive the same request after connection reset.
 fn backup_file_name(store_id: u64, region: &Region, key: Option<String>) -> String {
+    let start = SystemTime::now();
+    let since_the_epoch = start
+        .duration_since(UNIX_EPOCH)
+        .expect("Time went backwards");
     match key {
         Some(k) => format!(
-            "{}_{}_{}_{}",
+            "{}_{}_{}_{}_{}",
             store_id,
             region.get_id(),
             region.get_region_epoch().get_version(),
-            k
+            k,
+            since_the_epoch.as_millis()
         ),
         None => format!(
             "{}_{}_{}",

components/backup/tests/integrations/test_backup.rs

@@ -590,8 +590,17 @@ fn test_backup_rawkv() {
         &tmp.path().join(format!("{}", backup_ts.next().next())),
     );
     let resps3 = block_on(rx.collect::<Vec<_>>());
-    assert_eq!(files1, resps3[0].files);
-
+    let files3 = resps3[0].files.clone();
+
+    // After https://github.com/tikv/tikv/pull/8707 merged.
+    // the backup file name will based on local timestamp.
+    // so the two backup's file name may not be same, we should skip this check.
+    assert_eq!(files1.len(), 1);
+    assert_eq!(files3.len(), 1);
+    assert_eq!(files1[0].sha256, files3[0].sha256);
+    assert_eq!(files1[0].total_bytes, files3[0].total_bytes);
+    assert_eq!(files1[0].total_kvs, files3[0].total_kvs);
+    assert_eq!(files1[0].size, files3[0].size);
     suite.stop();
 }