Limitations and considerations

The following limitations apply:

• When replicating from a CHAR column, any trailing spaces will be truncated.
• Function-based indexes are not supported.
• If you are managing supplemental logging and you carry out transformations on any of the columns, you must be sure that supplemental logging is activated for all fields and columns.
• The AR_H_USER header column is supported only for Oracle database version 11.2.0.3 and higher. In Oracle database version 10, the value for this column may not be correct. For information on using header columns, see Headers.

• Connecting to a CDB is not supported.

• Deferred Constraints are not supported.
• The rename table <table name> to <new table name> syntax is supported by Qlik Replicate when using Oracle version 11 and higher.
• Data changes resulting from partition/sub-partition operations (ADD, DROP, EXCHANGE and TRUNCATE) will not be replicated and may cause the following errors:
  • For ADD operations, updates and deletes on the added data may return a "0 rows affected" warning.
  • For DROP and TRUNCATE operations, new inserts may result in "duplicates" errors.

  • For EXCHANGE operations, both a "0 rows affected" warning and "duplicates" errors may be encountered.

  To replicate changes resulting from partition/sub-partition operations, you need to reload the tables in question. When adding a new empty partition, operations on the newly added partition will be replicated to the target as normal.

• When Limited-size LOB mode is enabled, empty LOBs on the Oracle source are replicated as NULL values. For more information on Limited-size LOB mode, see Task Settings Metadata.
• Changes made by the Oracle DBMS_REDEFINITION package -( e.g. table metadata and the OBJECT_ID) - will not be captured by Qlik Replicate.
• Empty BLOB/CLOB columns are mapped to NULL on the target.
• During Change Processing, columns without supplemental logging (e.g. LOB columns) that are not updated will be inserted as NULL in the Change Table.

• During Change Processing, batch updates to numeric columns defined as a Primary Key are not supported.

  Example of an unsupported UPDATE command:

  UPDATE tableX set ID=ID+1;

  Where tableX is the table name and ID is a numeric column defined as a Primary Key.

• LONG and LONG RAW column limitations:

  • Data in LONG and LONG RAW columns cannot exceed 64k. Any data that exceeds 64k will be truncated.

  • The Allow unlimited LOB size option is not supported when loading LONG and LONG RAW columns into Oracle target.

    Workaround: Use the Limit LOB size to (KB) option instead.

• Tables whose names contain apostrophes cannot be replicated.
• Change Data Capture (CDC) is not supported from dynamic views.
• Index-organized tables with an overflow segment are not supported in Change Processing (CDC) tasks.
• During CDC or during Full Load when the Allow unlimited LOB size option is enabled, LOB data types are supported only in tables with a primary key or unique index.
• Changes to Index-organized tables with key compression are not supported.
• Replication of tables or views of type BIN$ or DR$ is not supported.

• Oracle Flashback Database and restore points are not supported as the related operations affect the consistency of Oracle redo log files.

• When using Oracle LogMiner to access the redo logs, the following limitations apply:
  • UPDATEs to XMLTYPE and LOB columns are not supported (i.e. replicated).
  • SHRINK SPACE operations are not supported
  • Connecting to a PDB using Oracle LogMiner is not supported. Therefore, if you want to connect to a PDB, make sure that the Access redo logs via Replicate Log Reader option is selected in the Advanced tab.
  • Due to unpredictable behavior, it is not recommended to use Oracle LogMiner when replicating from a RAC environment.
• When using Replicate Log Reader to access the redo logs, the following limitations apply:
• Table clusters are not supported.
• Only table-level SHRINK SPACE operations are supported. These include the full table, partitions, and sub-partitions.
• Implementing online redo logs on raw devices is not supported.
• The following Oracle features are not supported when using Amazon RDS for Oracle:
  • ASM
  • TDE

• Direct-load INSERT procedure with parallel execution option is not supported for tables with more than 255 columns, or when a row size is greater than 8K.

• When using the escape character '\' to search for a table in the Select Tables window, you need to write '\\' (2 backslashes) instead of '\' (1 backslash). For example, to search for all tables that include '_', you would need to enter %\\_%.
Information note
• When adding a pattern for include or exclude, 2 backslashes are not required (for example, *%\_%).

• When using '$’ for the escape character, there is no limitation.
• When using Oracle 19.0 as the source, the following Oracle features are not supported:
  • Data-guard DML redirect
  • Partitioned hybrid tables
  • Schema-only Oracle accounts

• As the Oracle database does not generate a FULL after-image, the following limitation applies:

  When UPDATEs are applied in Batch optimized apply mode, neither the INSERT the missing target record error handling option for missing records nor the Apply Changes using SQL MERGE option are supported. If either of these options is selected, NULL will be inserted in the target columns for all unchanged user-defined data.

• When filtering records that do not contain a Primary Key, capture of DELETE operations on records that do not have full supplemental logging on the columns included in the filtering condition is not supported.

• Object names exceeding 30 characters are not supported. Consequently, tables with names exceeding 30 characters or tables containing column names exceeding 30 characters will not be replicated.

• When the task settings' Allow unlimited LOB size option is selected, LOB columns (CLOB, BLOB, NCLOB) with an empty_lob() value will be replicated as empty_lob(). In all other cases, a NULL value will be replicated instead of empty_lob().

• The task settings' Allow unlimited LOB size option is not supported.

• Replication from Application Containers is not supported.

• Cascading standby database is not supported.

• Failover configuration is supported only when changes are captured from the primary node.

Unsupported data types

The following data types are not supported:

• BFILE
• ROWID
• REF
• UROWID
• ANYDATA
• SDO_GEOMETRY
• User-defined data types