9.7. Large Objects (LOBs)

Large Objects (LOBs) consist of data. The three main large object runtime data types used by JBoss are:

These benefits are achieved if the Connector itself does not materialize an entire LOB all at once. For example, the JDBC API supports a streaming interface for BLOB and CLOB data.

Source LOB values are typically accessed by reference, rather than having the value copied to a temporary location. Care must be taken to ensure that source LOBs are returned in a memory-safe manner.

LOBs are broken into pieces when being created and streamed. The size of each piece when fetched by the client can be configured.

Cached lobs will be copied rather than relying on the reference to the source lob.

Temporary lobs created by Teiid will be cleaned up when the result set or statement is closed. To rely on implicit garbage collection based cleanup instead of statement close, the Teiid session variable clean_lobs_onclose can be set to false (by issuing the query "SELECT teiid_session_set('clean_lobs_onclose', false)" - which can be done for example via the new connection sql in the datasource definition). This can be used for local client scenarios that relied on the implicit behavior, such as Designer generated REST VDBs.