Chapter 21: In-Row Off-Row LOB


Overview

Adaptive Server supports the storage of in-row LOB columns for text, image, and unitext datatypes when they are small, and subject to available space in the page. When a LOB expands in size or its space is used for other in-row columns (such as those used for varchar and varbinary datatypes), Adaptive Server seamlessly migrates the in-row LOB data to off-row storage, automatically replacing the data with an in-row text pointer.

You can use:

When you map Component Integration Services (CIS) proxy tables to remote Adaptive Server tables that contain in-row LOB columns, you must define the LOB columns in the proxy tables as off-row LOBs. All data transmissions occur as off-row LOB column data.

In versions earlier than 15.7, Adaptive Server always stored large object (LOB) columns (such as text, image, unitext, and XML) off-row, using a text pointer (txtptr) to identify the start page ID value, and storing the pointer in the data row. This includs serialized Java classes, which are stored in-row only if they are shorter than a fixed maximum length.