What is coalesce tablespace in Oracle 11g?

Coalesce simply takes contigous free extents and makes them into a single bigger free extent. It is not a reorganization tool. It is a command to take any free extents that are right next to some other free extent and make one bigger free extent out of them.

How do I reclaim unused spaces in Oracle 11g?

If the datafile name must remain the same do the following:

1. Create a new tablespace.
2. Move the segments to the new tablespace.
3. Resize the original datafile.
4. Move the segments back to the original tablespace.
5. Drop the new tablespace.

Which are the mandatory tablespaces in Oracle 11g database?

Oracle comes with the following default tablespaces: SYSTEM , SYSAUX , USERS , UNDOTBS1 , and TEMP .

• The SYSTEM and SYSAUX tablespaces store system-generated objects such as data dictionary tables.
• The USERS tablespace is helpful for ad-hoc users.
• The UNDOTBS1 holds the undo data.

How do I enable Autoextend in Oracle tablespace?

The following example enables automatic extension for a datafile added to the users tablespace: ALTER TABLESPACE users ADD DATAFILE ‘/u02/oracle/rbdb1/users03. dbf’ SIZE 10M AUTOEXTEND ON NEXT 512K MAXSIZE 250M; The value of NEXT is the minimum size of the increments added to the file when it extends.

What is Dba_data_files?

DBA_DATA_FILES describes database files. The size of the file available for user data. The actual size of the file minus the USER_BYTES value is used to store file related metadata.

How do I reclaim a space in Oracle?

Here are the high-level steps that will be performed.

1. Create an ASM Disk Group using the ASM Filter Driver.
2. Create a tablespace in this diskgroup and populate it with some random data.
3. Check the space allocated at the database and array level.
4. Drop the tablespace and run ASM rebalance.
5. Check the space again.

What are the different types of tablespaces?

There are three types of tablespaces:

• Permanent. You use permanent tablespaces to store your user and application data.
• Undo. A database running in automatic undo management mode transparently creates and manages undo data in the undo tablespace.
• Temporary.

What is Maxbytes in DBA_DATA_FILES?

When we query the DBA_DATA_FILES table (for scripting), we need to take extra care while getting data from MAXBYTES column. Notice the MAXBYTES value is 0 for the last 2 datafiles. The reason for this is because during the creation of the datafile, the MAXSIZE was not specified.

What is Increment_by in DBA_DATA_FILES?

Maximum file size in blocks. INCREMENT_BY. NUMBER. Number of tablespace blocks used as autoextension increment. Block size is contained in the BLOCK_SIZE column of the DBA_TABLESPACES view.

When do you want to ” coalesce ” a tablespace?

In the olden days of lore, when dictionary managed tablespaces were the only thing going – you sometimes, under some conditions wanted to “coalesce a tablespace” – that would combine adjacent free extents into a single free extent (something SMON does in the background quite nicely, this was just a way to force it to happen right now).

How does the COALESCE function work in Oracle?

The Oracle docs note that the coalesce partition syntax behave differently, depending on the type of partition: “When a hash partition is coalesced, its contents are redistributed into one or more remaining partitions determined by the hash function.

How to reclaim unused space in Oracle Database?

Temp Tablespace If you are using oracle 11g, you can shrink a temporary tablespace using the ALTER TABLESPACE command, as shown here. If you are using a database version prior to 11g, reducing the size of the temporary tablespace is similar to reclaiming space from the undo tablespace.

How to alter tablespace in Oracle DBA database?

SQL> alter tablespace users coalesce; Tablespace altered. The solution was to purge the tablespace’s recycle bin, even if there were no recycled objects near the end of the datafile. Furthermore, before I begin all this procedure, I had purged the database’s recycle bin, using “PURGE DBA_RECYCLEBIN”.