Select the version of your MapR cluster. This cluster must host the MapR-DB database to be used.

Schema and Edit schema

A schema is a row description. It defines the number of fields
(columns) to be processed and passed on to the next component. When you create a Spark
Job, avoid the reserved word line when naming the
fields.

• Built-In: You create and store the schema locally for this component
  only.

• Repository: You have already created the schema and stored it in the
  Repository. You can reuse it in various projects and Job designs.

• View schema: choose this
  option to view the schema only.

• Change to built-in property:
  choose this option to change the schema to Built-in for local changes.

• Update repository connection:
  choose this option to change the schema stored in the repository and decide whether
  to propagate the changes to all the Jobs upon completion. If you just want to
  propagate the changes to the current Job, you can select No upon completion and choose this schema metadata
  again in the Repository Content
  window.

This component supports the Document type. If a field is for entire
documents, select Document in the Type column for this field in the schema editor.

Click Sync
columns to retrieve the schema from the previous component connected in the
Job.

Use kerberos authentication

If you are accessing a MapR-DB as-OJAI database
running with Kerberos security, select this check box, then, enter the Kerberos
principal name and password in the displayed fields.

Every time when you launch your Job, the
component submits this authentication information to Kerberos for a new kinit
ticket.

Select the Use a keytab to authenticate
check box to log into a Kerberos-enabled system using a given keytab file. A keytab
file contains pairs of Kerberos principals and encrypted keys. You need to enter the
principal to be used in the Principal field and
the access path to the keytab file itself in the Keytab field. This keytab file must be stored in the machine in
which your Job actually runs, for example, on a Talend Jobserver.

Note that the user that executes a keytab-enabled Job is not necessarily
the one a principal designates but must have the right to read the keytab file being
used. For example, the user name you are using to execute a Job is user1 and the principal to be used is guest; in this
situation, ensure that user1 has the right to read the keytab
file to be used.

Restrict partial sorts with Secondary Indexes

Select this check box to force the query to explicitly sort on the actual
data. This way, you avoid in your query the partial sorts that could
otherwise occur due to the asynchronous secondary indexes.

For further information about this partial sorts issue of MapR OJAI, see
Asynchronous Secondary Index
Updates from the MapR documentation.

Do not select this check box if you do not expect to encounter the lags
in the asynchronous indexes or you know that the impact of the lags is
trivial. By keeping this check box clear, your query benefits from the
ordering advantages provided by the secondary indexes of MapR-DB JSON
tables.

Table name

Enter the name of the table to be processed.

Query

Specify the where clause of the query to be performed by
tMapROjaiInput.

For example, type in "{id:{$eq:
4}}" or "{id:4}}"to retrieve the record in
which id is 4.

As OJAI uses MongoDB query format for queries, see Query Operators from the
MongoDB documentation for available operators.

Mapping

Each column of the schema defined for this component represents a field of the documents
to be read. In this table, you need to specify the parent nodes of these fields, if
any.

tStatCatcher Statistics

Select this check box to gather the Job processing metadata at the Job level
as well as at each component level.

Global Variables

ERROR_MESSAGE: the error message generated by the
component when an error occurs. This is an After variable and it returns a string. This
variable functions only if the Die on error check box is
cleared, if the component has this check box.

NB_LINE: the number of rows read by an input component or
transferred to an output component. This is an After variable and it returns an
integer.

A Flow variable functions during the execution of a component while an After variable
functions after the execution of the component.

To fill up a field or expression with a variable, press Ctrl +
Space to access the variable list and choose the variable to use from it.

For further information about variables, see
Talend Studio

User Guide.

Usage rule

tMapROjaiInput executes queries to read data from a
given MapR-DB database. It is a starting component of a Job and requires
an outgoing link to send data to its following component.