Creating a Cache

Use the RTView Builder to create a cache in a separate .rtv file, then import the file into the main dashboard file.

A cache is a datasource that allows users high-speed analytic processing of real-time data and the comparison of current real-time values against historical data. It is an intermediate datasource when connecting a dashboard object to an Event Stream Processor data stream that produces updates and deletes against user-entered values. From the RTView Builder:

  1. Select File > New to create a new .rtv file.
  2. Select Tools > Caches, then click Add in the Caches tab at the bottom of the main Display Builder window.
  3. Enter a name for the new cache and set its type to Table.
  4. Edit the cache properties:
    Property Procedure
    valueTable
    1. Right-click valueTable and select Attach To Data > ESP.
    2. Select the name of the stream that the cache subscribes to.
    3. (Optional) Choose specific stream columns; however, if you select specific columns, you must select the primary-key columns.
    indexColumnNames
    1. Click the ellipsis (...) beside the indexColumnNames field.
    2. Specify the key columns for the stream, separating the column names with a semicolon. The column names are case-sensitive.
    rowsToDeleteTable rowsToDeleteTable is a data attachment that removes selected rows from the cache tables. Rows are removed if their index column values match those of a row in the table data coming from this attachment.
    1. Right-click rowsToDeleteTable and select Attach To Data > ESP.
    2. Event Stream Processor does not have a rowsToDeleteTable, so you must use a virtual table name. For example, to use the Positions stream name, use !Positions for the rowsToDeleteTable property.
    maxNumberOfRows
    • Specify the number of rows of historical data to save. The default value is zero. Anything larger than zero enables storage of historical data. For every key value, N rows of history are maintained, where N is the number of rows specified.
  5. Save the file.
  6. Import this file to the main dashboard file. From the main dashboard file:
    1. Select Tools > Options > Caches.
    2. Click Add and select the cache created in step 3.
    3. Click Apply, then OK.
    Note: If you make any changes to the cache after importing it to the main display file, select Options > Caches > Refresh Selection.
  7. Save, then close, the file.
  8. Repeat steps 1 to 7 for every cache you are creating.
Parent topic: Dashboard Objects and Data Streams