What is Securefile LOB?

The original LOB storage, now known as BASICFILE , is still the default storage method, but the SECUREFILE keyword enables the new storage method, which allows encryption for security and space savings using compression and deduplication.

How do you shrink a Securefile LOB?

Step 3 : Shrink the SecureFile LOB after rows are updated

  1. Update the CLOB. SQL> UPDATE hr.t1 SET a=a||a||a||a||a||a||a; 8 rows updated.
  2. Shrink the LOB segment.
  3. Display the number of extents or blocks freed.
  4. Update the CLOB.
  5. Shrink the LOB segment.
  6. Display the number of extents or blocks freed.

What is LOB in Oracle database?

Large Objects (LOBs) are a set of datatypes that are designed to hold large amounts of data. A LOB can hold up to a maximum size ranging from 8 terabytes to 128 terabytes depending on how your database is configured. Storing data in LOBs enables you to access and manipulate the data efficiently in your application.

How do I convert Basicfile to Securefile?

Migrate From Basicfile to Securefile

  1. Export the table, create a new table with the same columns with the secure file lob and import the data into the new table.
  2. Add securefile column to table, update with data in basicfile column.
  3. With the command ALTER TABLE table_name MOVE …

Can LOB columns be compressed?

Like normal columns memory LOBs are compressed. It is not possible to compress and deduplicate LOB data.

How do you reclaim space from a lob segment?

Use DBMS_REDEFINITION to reorganize the LOB segment, This is the Best Way to reclaim space from a LOB segment. Also use “COMPRESS MEDIUM” and SECURE FILE clause, while creating the interim table. There is no reason for you to use BASIC FILE. This is ONLINE process, meaning your app can stay up…

How are LOBs stored in Oracle?

Only the LOB locator is stored in the table column; BLOB and CLOB data can be stored in separate tablespaces and BFILE data is stored as an external file. For inline LOBs, the database stores LOBs that are less than approximately 4000 bytes of data in the table column.

How do you find a table with LOBs?

Following are the steps to find LOB segment belong to which table name

  1. Check the large size of segment present in the database. col owner for a6. col segment_name for a26.
  2. Find the LOB belong to which tablespace. select e.owner,l.table_name,l.segment_name.
  3. Get the list of LOB objects present in database.

What is Oracle SecureFiles?

Starting with Oracle Database 12c, SecureFiles is the default storage mechanism for LOBs in Oracle. In Oracle Database 11g Release1, ‘BASICFILE’ is the default storage LOB storage type. The keyword ‘SECUREFILE’ is used for specifying SecureFiles. The default LOB storage can be changed using the db_securefile parameter.

How do you set a LOB?

You can provide the LOB storage characteristics when creating a LOB column using the CREATE TABLE statement or the ALTER TABLE ADD COLUMN statement….11.1 Creating a New LOB Column

  1. 1 CREATE TABLE BNF.
  2. 2 ENABLE or DISABLE STORAGE IN ROW.
  3. 3 CACHE, NOCACHE, and CACHE READS.
  4. 4 LOGGING and FILESYSTEM_LIKE_LOGGING.

What is LOBs Hana?

Since SPS06, SAP HANA offers a flexibility around how it manages data type LOB (Large Object Types) columns, namely Hybrid LOBs. Data types, CLOB, NCLOB and BLOB are used to store a large amount of data such as text documents and images. The current maximum size for an LOB on SAP HANA is 2GB.