Streaming

Description

Large recordsets can exceed PHP's memory limit. Structures_DataGrid offers streaming support with many DataSource drivers and some Renderer drivers to avoid problems with the memory limit.

How do I use streaming?

Streaming can be enabled by calling the enableStreaming() method of the Structures_DataGrid object. An optimal parameter allows to set the number of records that should be read and written on each stream iteration. The default buffer size is 500 records.

Once streaming is enabled, only up to the number of records specified in the buffer size records will be fetched and rendered. This will be repeated until this was done for all records.

<?php
require 'Structures/DataGrid.php';

// Instantiate the DataGrid
$datagrid =& new Structures_DataGrid();

// Enable streaming and set buffer size to 1,000 records
$datagrid->enableStreaming(1000);

// ... e.g. bind(), render() calls as usual
?>

Driver support for streaming

Although streaming can be used with every DataSource driver, only the following drivers support streaming in a meaningful way: DataObject, DBQuery, DB_Table and MDB2. Streaming support is planned to be added also to the CSV and XML DataSources.

Streaming support is also compatible with every Renderer driver but can currently be used only with CSV and XML Renderers in a meaningful way. Other Renderers might be rewritten in the future for streaming support.