How do I know if tablespace is fragmented?

How do I know if tablespace is fragmented?

To see if you suffer from “fragmentation”, you can query DBA_FREE_SPACE (best to do an alter tablespace coalesce first to ensure all contigous free regions are made into 1 big free region). DBA_FREE_SPACE will report the size of all free extents.

How do I fix tablespace fragmentation in Oracle?

Elimination of Fragmentation

  1. Perform an export on all objects in the tablespace.
  2. Drop the tablespace using the INCLUDING CONTENTS clause.
  3. Re-create the tablespace (if you created a script to create the tablespace, you can just re-run the script, be sure to include all active data files.

How do I view datafiles in tablespace?

You can view all the tablespace in your system from the dba_tablespace as shown below. SELECT * from DBA_TABLESPACES; To view all the datafiles of a particular tablespace, execute the following command. This command will display all the datafiles that as currently associated with thegeekstuff tablespace.

How do I check my tablespace status?

To get the tablespace for a particular Oracle table: SQL> select tablespace_name from all_tables where owner = ‘USR00’ and table_name = ‘Z303’; To get the tablespaces for all Oracle tables in a particular library: SQL> select table_name, tablespace_name from all_tables where owner = ‘USR00’;

What is fragmentation in Oracle tablespace?

A tablespace can contain many different segments for different database objects. Each of these extents can be a different size. As extents are added to the tablespace, the different size extents are intermixed. If one of the smaller extents is dropped, it leaves a hole of 500KB.

What is Oracle DB fragmentation?

Fragmentation comes with when we update/delete data in table. The space which gets freed up during non-insert DML operations is not immediately re-used (or sometimes, may not get reuse ever at all). This leaves behind holes in table which results in table fragmentation.

What is oraInventory and its purpose?

The directory that you designate as the Oracle Inventory directory (oraInventory) stores an inventory of all software installed on the system. If you have previous Oracle software installations on a server, then additional Oracle software installations detect this directory from the /etc/oraInst.

How can I check my datafiles status?

To determine whether datafiles require media recovery:

  1. Start SQL*Plus and connect to the target database instance.
  2. Determine the status of the database by executing the following SQL query:
  3. Query V$DATAFILE_HEADER to determine the status of your datafiles.

How do I add a datafile to a tablespace in Oracle?

To add datafiles to a tablespace, use either the Add Datafile dialog box of Enterprise Manager/GUI, or the SQL command ALTER TABLESPACE. You must have the ALTER TABLESPACE system privilege to add datafiles to a tablespace.

How do you check the size of the datafile in Oracle?

The size of the database is the space the files physically consume on disk. You can find this with: select sum(bytes)/1024/1024 size_in_mb from dba_data_files; But not all this space is necessarily allocated.

How do I defrag in Oracle?


  1. STEP 1: First Gather table statistics.
  2. Step 2: Check table size from dba_segments.
  3. STEP 3: Check actual table size, fragmented size and percentage of fragmentation in a table.
  4. STEP 4: Check the indexes on the table.
  5. STEP 5: Remove fragmentation by moving tables to same tablespace.
  6. STEP 6: Rebuild the indexes.

What is table redefinition in Oracle?

Oracle Database provides a mechanism to make table structure modifications without significantly affecting the availability of the table. The mechanism is called online table redefinition. Redefining tables online provides a substantial increase in availability compared to traditional methods of redefining tables.

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