10 Distributed LOBs

This section describes the ways in which you can work with LOB data in remote tables.

Distributed LOBs are LOBs that are fetched from one server to another, and may optionally be returned to the client. Distributed LOBs can be persistent or temporary LOBs for both reference and value LOB columns.

In sharding, a table is horizontally partitioned with subsets of rows in a table stored in different sharded databases. The client connects to the coordinator database, which in turn works with shards to provide a consolidated view of a table. Sharded LOBs are an extension of Distributed LOBs. LOB data between different shards is transported as distributed LOBs and the result is provided to the client through the coordinator database.

All Persistent LOBs and Temporary LOBs originating from JSON support Distributed and Sharded LOBs.

See Also:

Sharding with LOBs

• Working with Remote LOBs in SQL and PL/SQL
  This section describes the SQL and PL/SQL functions that are supported on remote LOBs.
• Using the Data Interface on Remote LOBs
  The data interface enables you to bind and define a CHARACTER buffer for a CLOB column and a RAW buffer for a BLOB column. This interface is supported for remote LOB columns too.
• Working with Remote Locators
  You can select a persistent LOB locator from a remote table into a local variable and this can be done in any programmatic interface like PL/SQL, JDBC or OCI. The remote columns can be of type BLOB, CLOB or NCLOB.