9.4. Filter Reference

The different filter types configured and available within Tungsten Replicator are designed to provide a number of different functionality and operations. Since the information exchanged through the THL system contains a copy of the statement or the row data that is being updated, the filters allow schemas, table and column names, as well as actual data to be converted at the stage in which they are applied.

Filters are identified according to the underlying Java class that defines their operation. For different filters, further configuration and naming is applied according to the templates used when Tungsten Cluster is installed through tpm.

Tungsten Replicator also comes with a number of JavaScript filters that can either be used directly, or that can be modified and adapted to suit individual requirements. These filter scripts are located in tungsten-replicator/support/filters-javascript.

For the purposes of classification, the different filters have been categorised according to their main purpose:

  • Auditing

    These filters provide methods for tracking database updates alongside the original table data. For example, in a financial database, the actual data has to be updated in the corresponding tables, but the individual changes that lead to that update must also be logged individually.

  • Content

    Content filters modify or update the content of the transaction events. These may alter information, for the purposes of interoperability (such as updating enumerated or integer values to their string equivalents), or remove or filter columns, tables, and entire schemas.

  • Logging

    Logging filters record information about the transactions into the standard replicator log, either for auditing or debugging purposes.

  • Optimization

    The optimization filters are designed to simplify and optimize statements and row updates to improve the speed at which those updates can be applied to the destination dataserver.

  • Transformation

    Transformation filters rename or reformat schemas and tables according to a set of rules. For example, multiple schemas can be merged to a single schema, or tables and column names can be updated

  • Validation

    Provide validation or consistency checking of either the data or the replication process.

  • Miscellaneous

    Other filters that cannot be allocated to one of the existing filter classes.

In the following reference sections:

  • Pre-configured filter name is the filter name that can be used against a stage without additional configuration.

  • Property prefix is the prefix string for the filter to be used when assigning property values.

  • Classname is the Java class name of the filter.

  • Parameter is the name of the filter parameter can be set as a property within the configuration.

  • Data compatibility indicates whether the filter is compatible with row-based events, statement-based events, or both.