translate 10-pg_clean

docs/guide/10-pg_clean.en.md

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+# V2.3.0 upgrade feature pg_clean usage instructions
+
+## 1. Install the pg_clean tool：
+Connect to any main CN：
+
+```
+CREATE EXTENSION pg_clean;
+```
+
+## 2. Two-Phase Transaction Case：  
+session1—cn1 
+
+```  
+begin; 
+create table a (id int); 
+prepare transaction 'create_a';
+set xc_maintenance_mode = on;
+execute direct on (dn002) 'rollback prepared ''create_a''';
+set xc_maintenance_mode = off;
+\q
+```
+
+In this use case, we create a two-phase transaction with gid 'create\_a', and then turn on xc\_maintenance\_mode so that the transaction only executes rollback in dn002.
+
+## 3. Find remnants of two-phase transactions in a cluster：
+session2—cn2  
+
+```
+select * from pg_clean_check_txn();
+```
+![pg_clean_check_txn](images/v.2.3.0_pg_clean_check_txn.png)
+
+The above figure prints out the remaining two-phase transactions in the cluster. Among them, gid represents the global identifier of the transaction, global\_transaction\_status represents the global status of the transaction, and transaction\_status\_on\_allnodes represents the status of the transaction in all nodes.
+
+## 4. View 2PC residual file names
+
+Query all 2PC residual file names under the data directory pg_2pc in node cn1
+
+session1—cn1 
+
+```
+	postgres=# select * from pgxc_get_record_list();
+	 pgxc_get_record_list 
+	----------------------
+	 create_a
+	(1 row)
+```
+
+## 5. Clean up the remnants of two-phase transactions in the cluster：
+session2—cn2
+
+```
+select * from pg_clean_execute();
+```
+![pg_clean_execute](images/v2.3.0_pg_clean_execute.png)
+
+The above image prints all remaining two-phase transactions, and the operations performed on them. Where operation represents the operation performed on each node of the transaction, and operation\_status represents whether the operation was successfully executed. Since the global transaction status of the transaction is ABORT, we go to each node with the prepare status to perform a rollback operation on the transaction.
+
+## 6. Check whether the cleaned two-phase transaction has any remaining file records：
+session1—cn1
+
+```
+	postgres=# select * from pgxc_get_record_list();
+	 pgxc_get_record_list 
+	----------------------
+
+	(1 row)
+```
+
+Since pg\_clean\_execute was successfully executed in the previous step, the file records of the rolled back transaction 'create_a' on all nodes have been deleted. Here we view all 2pc file records in cn1, which is displayed as empty and the result is correct.