Creating virtual tables for Logstream

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Use the New Virtual Table Wizard to create a new Logstream virtual table.

Procedure

  1. Expand the SQL > Data > SSID node, where SSID is the name of your server.
  2. Right-click Virtual Tables and select Create Virtual Table(s).
  3. Under Wizards, select the Logstream wizard and click Next.
  4. On the New Virtual Table Wizard page, complete the following fields and click Next:
    FieldAction
    Name Enter a unique name. The name can contain a maximum of 50 characters. The name must consist of an uppercase letter followed by zero or more characters, each of which is an uppercase letter, a digit, or the underscore character.
    Metadata Library From the drop-down list, select the target library where the virtual table metadata will be stored (for example, hlq.USER.MAP). The target libraries are specified in the server's started task JCL.
    Schema Name From the list of defined Schemas, select a Schema for the virtual table.
    Description Enter an optional description.
    Convert VAR* fields to True VAR* fields This is a deprecated field and should not be selected.
    Arrays Handling Enable one of the following array management options:
    • Flatten arrays into a single fixed table at runtime: This relates to multiple occurring (MU) fields and periodic (PE) groups.
    • Return arrays into separate tables at runtime: This relates to multiple occurring (MU) fields and periodic (PE) groups. A subtable is generated for each array. Subtables only support read access.
    • Flatten arrays now: If you select this option, you cannot change array-handling after you save the virtual table.
  5. On the Source Download page, completethe following fields and click Next:
    FieldAction
    Available Source Libraries Select the source library that contains the data structure to use.
    Source Library Members Select the PDS members that represent the data structures to include and click Download to copy the members from the mainframe to your desktop. Use Filter patterns to filter the list.
    Download Source Files Select one or more previously downloaded members.
  6. On the Virtual Table Layout page, complete the following fields and click Next:
    FieldAction
    Source

    Browse the source tree to verify that it displays the expected data layout. By default, all of the fields in the tree will be included in the mapping. To include only a subset of the fields for the mapping, modify the start field value and, optionally, the end field value, as follows:

    • For the start field, accept the default root start field, or expand the tree and select a different start field. When selecting a different start field, Enable End Field Selection must not be selected.
    • For the end field, accept the default end field, or expand the tree and select a different end field. When selecting a different end field, Enable End Field Selection must be selected.
    Start Field Identifies the first field within the data layout that will be mapped. To change this value, make sure Enable End Field Selection is not selected, and select a different start field in the Source tree.
    Enable End Field Selection Use this field to control selection of the start field and end field values in the Source tree. When this option is not selected (default), you can select the start field. When this option is selected, you can select the end field.
    End Field Identifies the last field within the data layout that will be mapped. To change this value, make sure Enable End Field Selection is selected, and select a different end field in the Source tree.
  7. Optional: On the Virtual Table Redefines page, accept the default table redefines or expand Redefine to modify your selection, and click Next.
  8. Click Finish.
  9. On the Data Source Details page, complete the following data source fields and click Next:
    FieldAction
    Data Set Name Enter the Logstream data set name you want to use.
    Post-Read Exit Name To manipulate the data after reading it from the source file, enter the name of the post-read exit to use. This is the custom exit routine that is installed on the server and is used to perform additional processing after a record is read from the data source.
    Advanced When reading large volumes of data from tables, click Advanced to display and configure the MapReduce feature. The MapReduce feature enables you to divide the data into logical partitions and process those partitions in parallel using the Thread Count value. At runtime, the number of zIIP processors is verified and one thread is used for each zIIP processor; resulting in improved performance. The Thread Count value you specify overrides the default value (2) and the discovered value. To disable MapReduce, select the Disable MapReduce check box.
  10. Click Finish.