# Limitations

When using the Amazon Target endpoint, the following limitation(s) apply:[](https://help.qlik.com/en-US/replicate/Content/Replicate/Main/Amazon%20Redshift/ARedshift_limitations.htm)

* The `ALTER TABLE <NAME> MODIFY COLUMN <NAME> <DATA_TYPE> DDL` is not supported.

* The [Allow unlimited LOB size](https://help.qlik.com/en-US/replicate/November2025/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/target_metadata.htm) option in the Target Metadata task settings is not supported.

* If you need to replicate 4-byte emoji characters, use a transformation to convert the data type from WSTRING(n ) to WSTRING ( n\*2 ).

* If you need to replicate JSON values, Redshift is limited by the following:

  * The duplicate attribute name cannot appear in the same object, but can appear in a nested object. By default, a data error is returned when a duplicate attribute is encountered in the same object. To choose how to handle duplicate attributes, see [Setting advanced connection properties](https://help.qlik.com/en-US/replicate/November2025/Content/Replicate/Main/Amazon%20Redshift/advanced_prop_redshift.htm)

  * JSON data is stored using the SUPER data type. Each SUPER object can contain up to 16 MB of data. By default a data error is returned when an object exceeds this limit. To choose how to handle objects exceeding 16 MB, see [Setting advanced connection properties](https://help.qlik.com/en-US/replicate/November2025/Content/Replicate/Main/Amazon%20Redshift/advanced_prop_redshift.htm)