EXECUTING A LARGE OBJECT FETCH QUERY AGAINST A DATABASE

摘要

A database server helps to streamline retrieval of lob values by making the decision of sending a locator in replacement of the lob value, or the lob value itself, depending upon the specific lob value being retrieved. A threshold value is determined in a fetch query, and lob sizes below that threshold are sent as values in a corresponding fetch response, and lengths above are sent as locators in the fetch response. Indicators are inserted in a fetch parameter of the response to inform the receiving client about which form of retrieval was used for each requested lob value being returned. The use of the indicators provides for sending lob values to the client when the lob value is considered small, and sending the locator when the lob values a re considered large in comparison to the threshold value. Therefore, the use of distinct indicators in the parameter of the response provides for the server system making a dynamic decision of sending either the LOB locator or an inline LOB value in the response, depending upon the specific value of the LOB in comparison to the threshold value. For example, the LOB values below the threshold are sent as values in columns or fetch answers of the response, while the LO B values above the threshold are sent as locators in place of the LOB values. The fetch paramet er uses the distinct indicator values to help inform the client of the form of retrieval present in the response as a result of the query.