Table Size Does not Change After VACUUM FULL Is Executed on the Table

Symptom

A user runs the VACUUM FULL command to clear a table, the table size does not change.

Assume the table is named table_name. Possible causes are as follows:

No data has been deleted from the table_name table. Therefore, the execution of VACUUM FULL table_name does not cause the table size to change.
Concurrent transactions exist during the execution of VACUUM FULL table_name. As a result, recently deleted data may be skipped when clearing the table.

For the second possible cause, use either of the following methods:

Wait until all concurrent transactions are complete, and run the VACUUM FULL table_name command again.
If the table size still does not change, ensure no service operations are performed on the table, and then execute the following SQL statements to query the active transaction list status:
```
select txid_current();
```
The current XID is obtained. Then, run the following command to check the active transaction list:
```
select txid_current_snapshot();
```
If any XID in the active transaction list is smaller than the current transaction XID, stop the database and then start it. Run VACUUM FULL to clear the table again.