Chunk Size Expression (Magic xpa 3.x)
This property determines the amount of records to provide to the browser or rich client upon each request for additional records. The end user may therefore browse through records on a local record cache without having to return to the enterprise server for every new record or page. Setting the correct chunk size reduces redundant data transmission and server interaction. An expression used for this property evaluates to a numeric value. This expression is computed when a task is initialized.
For example, if this property is set to 100, when the task opens the enterprise server will pass the first 100 records to the client. This allows the end user to browse the first 100 records locally. When the end user tries to scroll beyond a given range of records, the client contacts the server and receives an additional batch of 100 records.
Each chunk of records is accumulated on the client as a local cache of records. If the end user goes to the end or beginning of the table, the local cache is cleared and the cache accommodates a single batch of records.
When Preload View is set to TRUE, it is good practice to make the chunk size large enough to hold all the records fetched from the database.
In most cases of simple line mode view of the data, the required chunk size may vary according to the size of each record and the estimated amount of records that will be scrolled through by the end user. If the task data view is designed to be scrolled through frequently and through a large amount of records, it is preferable to increase the chunk size. On the other hand, if the record size is large, it is preferable to reduce the chunk size, which reduces the amount of data transmitted for each data chunk. When no expression is defined for the property of such a task, the default chunk size is 30. The maximum size is 999, a larger value will be considered as 999.
A task that has no Main source does not require fetching a set amount of records. It is sufficient to provide only one record, the virtual record. Such a task should have its Chunk Size property set to 1. If you set the chunk size to be greater than 1, it brings unnecessary virtual records into your task source and slows your task load time down. When no expression is defined for the property of such a task, the default chunk size is 1.
Default: 0. If no chunk size is set, the default is 30 for a task with a Main source, or 1 for a task with no Main source.
Relevant interfaces: Browser and Rich Client tasks
Database specific: The chunk size is not supported for local databases.
How Do I Set the Number of Records in a Record Set that are Passed to the Browser?
