# Limitations and considerations

The following limitations apply:

* Sybase ASE primary/standby configuration is supported with the publish-and-subscribe model only (i.e. Warm standby/MSA is not supported).

* Only one Qlik Replicate task can be run per SAP Sybase ASE database.

* Rename table is not supported (e.g. `sp_rename 'Sales.SalesRegion', 'SalesReg;`)

* Rename column is not supported (e.g. `sp_rename 'Sales.Sales.Region', 'RegID', 'COLUMN';`)

* Zero values located at the end of binary data type strings are truncated when replicated to the target database. For example, `0x0000000000000000000000000100000100000000` in the source table will become `0x00000000000000000000000001000001` in the target table.

* The `reorg` `rebuild` index command is not supported.

* Clusters are not supported.

* Materialized views are not supported.

* Data capture from partitions is only supported from Sybase ASE 15 or later.

* Merge operations performed during CDC will result in an non-recoverable error.

* The WRITETEXT statement is not supported as it may result in duplicate (or more) inserts on the target.

* The Replicate AR\_H\_USER header column is not supported for database changes performed in auto-commit mode. For these changes, the header column will be empty.

* Rollback trigger on datarow locked tables is not supported.

* Replicating data with 4-byte emoji characters is not supported.