There is a directive for the ibm_db2 extension, ibm_db2.i5_dbcs_alloc, that allocates buffer space available to store character data. The default does not allow enough space for processing all DBCS characters. This default is said to confer some performance benefit when DBCS compatibility is not needed. Customers using DBCS languages should adjust this setting to allow the needed space.
Any version of Zend Server for IBM i running on any supported version of IBM i.
The ibm_db2.i5_dbcs_alloc directive can be set from the Zend Server User Interface in your web browser. To start, locate the directives for the ibm_db2 extension in the UI. Starting with version 8, the PHP directives are found on the PHP -> Extensions tab. For older versions of Zend Server, the PHP directives are found on the Configurations -> PHP tab.
Please find ibm_db2 on the list of extensions, and single-click to open the list of directives. Find the ibm_db2.i5_dbcs_alloc directive on the list. Select "use expanded allocations". Click the "Save" button at the top of the extensions list to save your changes. A restart will be required for the change to take effect.