# Limitations

When defining a task with Amazon MSK as the target endpoint, the following limitations apply:

* The Amazon MSK target endpoint does not support unlimited LOB size. Therefore, when replicating from source tables with LOB columns, *do not* select the Allow unlimited LOB size option.

  For more information on defining LOB settings, see [Target metadata](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/target_metadata.htm).

* Batch optimized apply mode is not supported. If this mode is set, the task will automatically switch to Transactional apply mode and issue an appropriate warning.

  For more information on these modes, see [Change Processing Tuning](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_applychangtunestab.htm).

* Store Changes mode is not supported.

  For more information on Store Changes mode, see [Adding tasks](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Design%20Tasks/tasks_setup.htm).

* Amazon MSK topic names cannot exceed 255 characters (249 from Kafka 0.10) and can only contain the following characters:

  a-z|A-Z|0-9|. (dot)|\_(underscore)|-(minus)

  If the source table names exceed the maximum permitted length or contain unsupported characters, you need to either modify the names before starting the task or define a global transformation. For information on defining global transformations, see [Starting the Global Transformation Rules wizard](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_newTransRuleWiz.htm).

* The [Ignore ALTER](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_applychangsetstab.htm#ignore_alter) Apply Changes setting is not supported for changes to source data types and table renaming.

* Column names must begin with [A-Za-z\_] (letters or an underscore) followed by [A-Za-z0-9\_] (letters, digits, or an underscore). For example, \_Test\_ is a valid column name whereas &Test is not.

  If a source column name does not adhere to this rule, then [a transformation should be used](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_useTransTable.htm) to rename the column.

* The [Drop and Create table](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_fullLoadSetstab.htm) Target Table Preparation option is not supported
* The [Truncate before loading](https://help.qlik.com/en-US/replicate/May2026/Content/Global_Common/Content/SharedEMReplicate/Customize%20Tasks/tasks_fullLoadSetstab.htm) Target Table Preparation option is not supported
* The Change Data Partitioning [Control table](https://help.qlik.com/en-US/replicate/May2026/Content/Replicate/Main/Control%20Tables/control_tables.htm) is not supported
* DDL Changes: Dropping or renaming a table is not supported