[chore](backup) Fix the db name of the restored view (apache#38075)

Cherry-pick apache#37412

Previously, during restore, the database name in the CREATE VIEW
statement was not modified, causing the restored view to be unviewable
with the SHOW VIEW command. This PR retains the original cluster's
database name in the BackupMeta and manually replaces it with the new
cluster's database name in the CREATE VIEW statement during restore.

fe/fe-core/src/main/java/org/apache/doris/backup/BackupJob.java

@@ -402,7 +402,7 @@ private void prepareAndSendSnapshotTask() {
             }
         }
 
-        backupMeta = new BackupMeta(copiedTables, copiedResources);
+        backupMeta = new BackupMeta(db.getName(), copiedTables, copiedResources);
 
         // send tasks
         for (AgentTask task : batchTask.getAllTasks()) {

fe/fe-core/src/main/java/org/apache/doris/backup/BackupMeta.java

@@ -39,6 +39,8 @@
 
 public class BackupMeta implements Writable {
 
+    @SerializedName(value = "db")
+    private String dbName;
     // tbl name -> tbl
     @SerializedName(value = "tblNameMap")
     private Map<String, Table> tblNameMap = Maps.newHashMap();
@@ -52,7 +54,9 @@ public class BackupMeta implements Writable {
     private BackupMeta() {
     }
 
-    public BackupMeta(List<Table> tables, List<Resource> resources) {
+    public BackupMeta(String dbName, List<Table> tables, List<Resource> resources) {
+        this.dbName = dbName;
+
         for (Table table : tables) {
             tblNameMap.put(table.getName(), table);
             tblIdMap.put(table.getId(), table);
@@ -62,6 +66,10 @@ public BackupMeta(List<Table> tables, List<Resource> resources) {
         }
     }
 
+    public String getDbName() {
+        return dbName;
+    }
+
     public Map<String, Table> getTables() {
         return tblNameMap;
     }

fe/fe-core/src/main/java/org/apache/doris/backup/RestoreJob.java

@@ -738,7 +738,8 @@ private void checkAndPrepareMeta() {
                         return;
                     }
                 } else {
-                    remoteView.resetIdsForRestore(env);
+                    String srcDbName = backupMeta.getDbName();
+                    remoteView.resetIdsForRestore(env, srcDbName, db.getFullName());
                     restoredTbls.add(remoteView);
                 }
             }

fe/fe-core/src/main/java/org/apache/doris/catalog/Database.java

@@ -222,6 +222,11 @@ public String getFullName() {
         return fullQualifiedName;
     }
 
+    public String getName() {
+        String[] strs = fullQualifiedName.split(":");
+        return strs.length == 2 ? strs[1] : strs[0];
+    }
+
     public void setNameWithLock(String newName) {
         writeLock();
         try {

fe/fe-core/src/main/java/org/apache/doris/catalog/View.java

@@ -240,8 +240,13 @@ public View clone() {
         return copied;
     }
 
-    public void resetIdsForRestore(Env env) {
+    public void resetIdsForRestore(Env env, String srcDbName, String dbName) {
         id = env.getNextId();
+
+        // the source db name is not setted in old BackupMeta, keep compatible with the old one.
+        if (srcDbName != null) {
+            inlineViewDef = inlineViewDef.replaceAll(srcDbName, dbName);
+        }
     }
 
     @Override

fe/fe-core/src/test/java/org/apache/doris/backup/BackupHandlerTest.java

@@ -212,7 +212,7 @@ public Status getSnapshotInfoFile(String label, String backupTimestamp, List<Bac
                 List<Table> tbls = Lists.newArrayList();
                 tbls.add(tbl);
                 List<Resource> resources = Lists.newArrayList();
-                BackupMeta backupMeta = new BackupMeta(tbls, resources);
+                BackupMeta backupMeta = new BackupMeta(null, tbls, resources);
                 Map<Long, SnapshotInfo> snapshotInfos = Maps.newHashMap();
                 for (Partition part : tbl.getPartitions()) {
                     for (MaterializedIndex idx : part.getMaterializedIndices(IndexExtState.VISIBLE)) {

fe/fe-core/src/test/java/org/apache/doris/backup/RestoreJobTest.java

@@ -252,7 +252,7 @@ boolean await(long timeout, TimeUnit unit) {
         List<Table> tbls = Lists.newArrayList();
         List<Resource> resources = Lists.newArrayList();
         tbls.add(expectedRestoreTbl);
-        backupMeta = new BackupMeta(tbls, resources);
+        backupMeta = new BackupMeta(null, tbls, resources);
     }
 
     @Test