How to query oracle user space

Oracle database is one of the most commonly used databases at present. Its use covers many fields such as enterprise-level applications, large-scale data warehouses and cloud solutions. In Oracle, each user is allocated a certain amount of space to store his own objects, such as tables, indexes, views, etc. Therefore, querying Oracle user space is very necessary.

There are many ways to query Oracle user space, which can be achieved through tools such as SQL query, Oracle Enterprise Manager (OEM) or PL/SQL Developer. This article will use SQL statements as an example to introduce how to query Oracle user space.

In the Oracle database, you can use the following SQL statement to query the spatial information of the current user:

SELECT 
    SUM(bytes/1024/1024) Total_MB,
    SUM(decode(segment_type,'TABLE',bytes,NULL))/1024/1024 as "TABLESPACE_MB",
    SUM(decode(segment_type,'INDEX',bytes,NULL))/1024/1024 as "INDEXSPACE_MB",
    SUM(decode(segment_type,'LOBSEGMENT',bytes,NULL))/1024/1024 as "LOBSPACE_MB",
    SUM(decode(segment_type,'LOBINDEX',bytes,NULL))/1024/1024 as "LOBINDEXSPACE_MB"
FROM 
    user_segments;

In the above SQL, user_segments is an Oracle system data dictionary view, which can provide the current user in the database. Statistics for all allocated space in the instance.

Among them, the bytes column represents the number of bytes occupied by the current object, and the segment_type column represents the type of object, which can include tables, indexes, LOBs (large objects), etc. The total number of bytes can be calculated through the SUM function. After being converted into MB units, it corresponds to the total used space, table space, index space, LOB space and LOB index space.

If you want to query the spatial information of all users, you can use the following SQL statement:

SELECT 
    username,
    SUM(bytes/1024/1024) Total_MB,
    SUM(decode(segment_type,'TABLE',bytes,NULL))/1024/1024 as "TABLESPACE_MB",
    SUM(decode(segment_type,'INDEX',bytes,NULL))/1024/1024 as "INDEXSPACE_MB",
    SUM(decode(segment_type,'LOBSEGMENT',bytes,NULL))/1024/1024 as "LOBSPACE_MB",
    SUM(decode(segment_type,'LOBINDEX',bytes,NULL))/1024/1024 as "LOBINDEXSPACE_MB"
FROM 
    dba_segments
GROUP BY username;

In the above SQL, dba_segments is the system data that contains the spatial statistical information used by all users in the database instance. Dictionary view. The group by statement is used to group statistics on space usage information by username.

It should be noted that when querying dba_segments, you need to have dba permissions to access this view.

In addition to the above methods, Oracle Enterprise Manager (OEM) also provides a visual interface that can query the spatial information of all users. The specific operations are as follows:

1. Open Oracle Enterprise Manager ( OEM) console. Select "Database" in the left menu bar, then select "Schema".
2. In the Schema page, you can see the space information of all users, including attributes such as scheme, table space name, used space and remaining space.

Through the above method, we can easily query the space information of Oracle users and grasp the usage of database storage space in a timely manner. This greatly helps the DBA or database administrator to manage and plan the database space, deal with issues such as insufficient space or waste of space in a timely manner, and improve database performance and reliability.

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