In-depth analysis of Oracle table space capacity query method

In-depth analysis of Oracle table space capacity query method

In Oracle database management, table space is an important component used to store tables, indexes, views and other objects in the database. part. Understanding the capacity of table spaces is crucial for database administrators, which can help them perform storage management and planning in a timely manner. This article will deeply analyze the method of Oracle table space capacity query and give specific code examples.

1. Query the current usage of table space

To query the current usage of table space, you can use the following SQL statement:

SELECT tablespace_name,
       round((1 - (free_space / total_space)) * 100, 2) AS used_percentage,
       free_space,
       total_space
FROM (SELECT tablespace_name,
             sum(decode(autoextensible, 'NO', bytes, maxbytes)) AS total_space,
             sum(decode(autoextensible, 'NO', bytes, maxbytes) - (bytes - blocks * block_size)) AS free_space
      FROM dba_data_files
      GROUP BY tablespace_name);

The above SQL statement will be listed The name, usage percentage, free space, and total space of each tablespace.

2. Query the usage of each data file in the table space

If you need to further understand the usage of each data file in each table space, you can execute the following SQL query:

SELECT file_id,
       file_name,
       tablespace_name,
       round((blocks * block_size) / 1024 / 1024, 2) AS file_size_mb,
       round(sum(bytes) / 1024 / 1024, 2) AS used_space_mb,
       round(sum(maxbytes - bytes) / 1024 / 1024, 2) AS free_space_mb,
       round((1 - (sum(bytes) / sum(maxbytes))) * 100, 2) AS used_percentage
FROM dba_data_files
GROUP BY file_id,
         file_name,
         tablespace_name,
         blocks,
         block_size;

The above code will return the ID, name, table space to which it belongs, file size, used space, free space and usage percentage of each data file.

3. Query the data files and table space usage of the table space

The following SQL statement can query the table space name, file name, used space and remaining space corresponding to each data file. ：

SELECT a.tablespace_name,
       b.file_name,
       round((a.bytes / 1024 / 1024), 2) AS file_size_mb,
       round((a.bytes - sum(nvl(b.bytes, 0)) / 1024 / 1024), 2) AS used_space_mb,
       round((sum(nvl(b.bytes, 0)) / 1024 / 1024), 2) AS free_space_mb
FROM dba_data_files a
LEFT JOIN dba_free_space b
ON a.file_id = b.file_id
GROUP BY a.tablespace_name,
         b.file_name,
         a.bytes;

Conclusion

Through the above detailed code examples, we can clearly understand how to query the capacity of the table space in the Oracle database. These queries are very useful for database administrators, which can help them monitor and manage the database storage space in a timely manner to ensure the normal operation of the system. Hope this article is helpful to readers.

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