Extracts data from datasets managed by a Terracotta server and runs RAQL queries over the data. The available datasets were either generated by an external application or by MashZone NextGen for materializing data feed results. You must select one of those two categories of datasets. Depending on your selection, the source operator shows different parameters.
To use the Terracotta source operator, you must configure a Terracotta connection in MashZone NextGen in advance. Terracotta connections can be defined in the MashZone NextGen Admin console. See Manage Terracotta connections.
The following parameters are available for the Datasets and Materialized Feeds source types.
Parameters |
Description |
Source |
Specifies the data source type.
Select a source type. |
Terracotta alias |
List of available Terracotta datasets for the configured connection aliases. Only Dataset aliases for which you have the Usage privilege are available. Select a Dataset alias. See Manage Terracotta connections for details. The option is available if the Datasets source type is selected. |
Materialized Feed |
List of available Materialized Feed aliases. Only Materialized Feed aliases for which you have the Usage privilege are available. Select the alias that defines the dataset with the Materialized Feed results. The corresponding dataset is available in the Dataset name drop-down menu. See Manage Materialized Feeds for details. The option is available if the Materialized Feeds source type is selected. |
Dataset name |
List of available Terracotta datasets for the configured connection alias. Select a dataset .The option is available if the Datasets source type is selected. |
Refresh rate () |
Specifies the time until the data source is read in again. Default value is 12 h. |
RAQL query |
Input field to enter any RAQL statement. Preset query: SELECT * FROM Dataset Dataset is the selected entry in the Dataset Alias drop-down box. |
Advanced options |
Specifies further parameters. |
Batch size |
Stream executions attempt (if possible) to optimize execution by transferring multiple elements simultaneously over the network. The Batch size option specifies the batch sizes to be used when transferring elements over the network. The Terracotta server can limit the actual value. For more information, please refer the corresponding Terracotta documentation. |
Insert parameter ( |
Inserts user defined input parameters at the cursor position. The button is clickable only if at least one user input parameter, for example, Text user input, has been inserted in the feed definition. For details, see RAQL and SQL statement parameters. |
Expand ( Collapse ( |
Expands or collapses the query input box. |
Configure columns |
Configures the columns of the dataset. The option is available if the Datasets source type is selected. When you select a dataset, schema guessing is used to derive its columns. Using 1000 records, the guessing mechanism derives the set of all unique cell definitions of those records and defines corresponding columns. Use Configure columns to display or modify that schema. Disable a column to exclude it from processing. Select or enter a (positive) Sample size and click Derive columns to re-run the schema guessing with a larger sample size, thereby omitting the current configuration. Note that the larger the sample size is, the longer the schema guessing takes. Click Add column to manually add a new column. Enter a unique column name and select a data type for the new column. Note that the combination of name and type must match the cell definition in the store. If the definition does not fit the definition, the corresponding values are always null. For example, if the cell definition is age with type INT and you specify age with type DOUBLE, the column definition does not match the cell definition and the values are null. |
For detailed information on configuring the time zone used by this operator, see the chapter Configure feed processing time zone.