Locators are small data structures that contain information for accessing actual data of large objects (LOBs).
Locators are directly stored in database tables, while data can be stored in database tables or separately. Separate tablespaces are usually used for LOBs.
The OceanBase JDBC driver (OceanBase Client) can perform the UPDATE TRUNCATE and READ operations on the LOB after obtaining an LOB locator. You can enable or disable LOB locators by configuring the URL options. supportLobLocator is enabled by default.
LOB prefetch
OceanBase Client prefetches metadata (such as the LOB length, block size, and the start and locator of the LOB data) during regular extraction operations to reduce the number of round trips. If the LOB column is selected in the result set, the server and JDBC driver allow you to prefetch some or all data to the client when obtaining the locator. Then, the read API call retrieves data from the prefetch buffer without a database round trip.