Avoid Queries That Return Large Resultsets

If the return of large resultsets is required by Dekho users, it is recommended to use OneSearch queries. OneSearch queries allow for large resultsets to be returned, with no impact on the database, as the information is being drawn from a search index.

For standard search queries, these should be designed to aim to return small resultsets to the client to avoid long wait times for the Dekho User that could lead to potential timeout issues or overloading the database server. It is important to consider the following:

Make use of multiple input parameters

Look at making some input parameters mandatory.

For spatial queries, determine the maximum number of records that can be returned from a query, and ensure this is not too large a result.

Where possible, pre-calculate as much information into separate attribute fields. e.g. If performing a spatial query to select properties in a postcode, would be quicker to execute if the a spatial join was performed beforehand, and a postcode attribute applied to the buildings layer.

Avoid increasing the maximum number of records returned by the server from its default 1000 value. Increasing it will have a performance hit and put more load on the GIS Server.


Make use of Database Indexes