Oracle tablespace map function description

 

1. tablespace map description

Both Oracle OEM and toad tools have a function called tablespace map.

 

The official Oracle 9i documentation describes the tablespace map function:

Http://docs.oracle.com/html/A86647_01/extent.htm

 

Tablespace map provides a specific view of space usage in each tablespace. It also contains the segment list in the tablespace and more detailed information about each segment, such:

(1) segment name

(2) segment type

(3) number of blocks allocated to segments

(4) number of zones allocated to segments

(5) Maximum number of zones that can be allocated to segments.

(6) The size (Kb) of the next partition that can be allocated to the segment ). Only segments in the tablespace used for dictionary management are displayed.

(7) the percentage increase in the size of the next area to be allocated. Only segments in the tablespace used for dictionary management are displayed.

 

In tablespacemap, the following information is displayed after you point to a zone:

(1) segment name

(2) block ID in the Partition

(3) Zone ID

(4) Partition size (number of blocks)

(5) complete name and path of the data file; Physical location of the Zone

 

Then we can view the following two aspects through tablespace map:

1. Objects in the tablespace

2. Table space extent usage, such as fragments.

 

For example, if we delete all objects in a tablespace, we can use tablespace map to check whether there are objects in the tablespace, this is also an intuitive method. There are only two reasons for this prompt: first, there are indeed objects, and second, data dictionary inconsistencies.

 

If the data dictionary is inconsistent, you can use the hcheck script for query. For details, refer:

Oraclehcheck script check data dictionary consistency description

Http://blog.csdn.net/tianlesoftware/article/details/7236457

 

 

2. View tablespace Map

 

2.1 use toad

Database --> diagnose --> tablespace Map

 

 

Here, the legend indicates that the window pops up. There are explanations of various colors.

 

 

2.2 Use OEM

Server --> tablespaces --> showtablespace contents --> Expand extent map

 

 

 

 

The tablespace map on the OEM has one more option than the toad, that is, the header will also be displayed.

 

The tablespace map function demonstrated in this blog is used to view fragments. A separate blog is organized for the fragmentation issue.

 

 

 

 

 

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------- Add a group to describe the relationship between Oracle tablespace and data files in the remarks section. Otherwise, reject the application ----

Dba1 group: 62697716 (full); dba2 group: 62697977 (full) dba3 group: 62697850 (full)

Super DBA group: 63306533 (full); dba4 group: 83829929 dba5 group: 142216823

Dba6 group: 158654907 dba7 group: 172855474 DBA group: 104207940