Presto Connection Details

Introduction

Connector Version

This documentation is based on version 23.0.8936 of the connector.

Get Started

Presto Version Support

Teradata/presto v0.194 and earlier, prestosql/presto v345 and earlier, prestodb/presto v0.242 and earlier are supported.

Establish a Connection

Connect to Presto

Set the Server and Port connection properties to connect, in addition to any authentication properties that may be required.

Secure Presto Connections

To enable TLS/SSL in the connector, set UseSSL to true.

Authenticate to Presto

Presto may be authenticated to by either LDAP or Kerberos. If the Presto server does not have authentication set up, leave AuthScheme set to NONE (default). In order to authenticate with either LDAP or Kerberos, follow the below steps:

LDAP

In order to authenticate with LDAP, set the following connection properties:

• AuthScheme: Set this to LDAP.
• User: The username being authenticated with in LDAP.
• Password: The password associated with the User you are authenticating against LDAP with.

Kerberos

Please see Using Kerberos for details on how to authenticate with Kerberos.

Use Kerberos

Kerberos

To authenticate to Presto with Kerberos, set AuthScheme to KERBEROS.

Authenticating to Presto via Kerberos requires you to define authentication properties and to choose how Kerberos should retrieve authentication tickets.

Retrieve Kerberos Tickets

Kerberos tickets are used to authenticate the requester's identity. The use of tickets instead of formal logins/passwords eliminates the need to store passwords locally or send them over a network. Users are reauthenticated (tickets are refreshed) whenever they log in at their local computer or enter kinit USER at the command prompt.

The connector provides three ways to retrieve the required Kerberos ticket, depending on whether or not the KRB5CCNAME and/or KerberosKeytabFile variables exist in your environment.

MIT Kerberos Credential Cache File

This option enables you to use the MIT Kerberos Ticket Manager or kinit command to get tickets. With this option there is no need to set the User or Password connection properties.

This option requires that KRB5CCNAME has been created in your system.

To enable ticket retrieval via MIT Cerberos Credential Cache Files:

1. Ensure that the KRB5CCNAME variable is present in your environment.
2. Set KRB5CCNAME to a path that points to your credential cache file. (For example, C:\krb_cache\krb5cc_0 or /tmp/krb5cc_0.) The credential cache file is created when you use the MIT Kerberos Ticket Manager to generate your ticket.

3. To obtain a ticket:

   1. Open the MIT Kerberos Ticket Manager application.
   2. Click Get Ticket.
   3. Enter your principal name and password.
   4. Click OK.

   If the ticket is successfully obtained, the ticket information appears in Kerberos Ticket Manager and is stored in the credential cache file.

The connector uses the cache file to obtain the Kerberos ticket to connect to Presto.

Keytab File

If your environment lacks the KRB5CCNAME environment variable, you can retrieve a Kerberos ticket using a Keytab File.

To use this method, set the User property to the desired username, and set the KerberosKeytabFile property to a file path pointing to the keytab file associated with the user.

User and Password

If your environment lacks the KRB5CCNAME environment variable and the KerberosKeytabFile property has not been set, you can retrieve a ticket using a user and password combination.

To use this method, set the User and Password properties to the user/password combination that you use to authenticate with Presto.

Enable Cross-Realm Authentication

More complex Kerberos environments can require cross-realm authentication where multiple realms and KDC servers are used. For example, they might use one realm/KDC for user authentication, and another realm/KDC for obtaining the service ticket.

To enable this kind of cross-realm authentication, set the KerberosRealm and KerberosKDC properties to the values required for user authentication. Also, set the KerberosServiceRealm and KerberosServiceKDC properties to the values required to obtain the service ticket.

Important Notes

Configuration Files and Their Paths

• All references to adding configuration files and their paths refer to files and locations on the Jitterbit agent where the connector is installed. These paths are to be adjusted as appropriate depending on the agent and the operating system. If multiple agents are used in an agent group, identical files will be required on each agent.

Advanced Features

This section details a selection of advanced features of the Presto connector.

User Defined Views

The connector allows you to define virtual tables, called user defined views, whose contents are decided by a pre-configured query. These views are useful when you cannot directly control queries being issued to the drivers. See User Defined Views for an overview of creating and configuring custom views.

SSL Configuration

Use SSL Configuration to adjust how connector handles TLS/SSL certificate negotiations. You can choose from various certificate formats; see the SSLServerCert property under "Connection String Options" for more information.

Proxy

To configure the connector using Private Agent proxy settings, select the Use Proxy Settings checkbox on the connection configuration screen.

Query Processing

The connector offloads as much of the SELECT statement processing as possible to Presto and then processes the rest of the query in memory (client-side).

See Query Processing for more information.

User Defined Views

The Presto connector allows you to define a virtual table whose contents are decided by a pre-configured query. These are called User Defined Views, which are useful in situations where you cannot directly control the query being issued to the driver, e.g. when using the driver from Jitterbit. The User Defined Views can be used to define predicates that are always applied. If you specify additional predicates in the query to the view, they are combined with the query already defined as part of the view.

There are two ways to create user defined views:

• Create a JSON-formatted configuration file defining the views you want.
• DDL statements.

Define Views Using a Configuration File

User Defined Views are defined in a JSON-formatted configuration file called UserDefinedViews.json. The connector automatically detects the views specified in this file.

You can also have multiple view definitions and control them using the UserDefinedViews connection property. When you use this property, only the specified views are seen by the connector.

This User Defined View configuration file is formatted as follows:

• Each root element defines the name of a view.
• Each root element contains a child element, called query, which contains the custom SQL query for the view.

For example:

{
    "MyView": {
        "query": "SELECT * FROM [Hive].[Default].Customers WHERE MyColumn = 'value'"
    },
    "MyView2": {
        "query": "SELECT * FROM MyTable WHERE Id IN (1,2,3)"
    }
}

Use the UserDefinedViews connection property to specify the location of your JSON configuration file. For example:

"UserDefinedViews", "C:\Users\yourusername\Desktop\tmp\UserDefinedViews.json"

Define Views Using DDL Statements

The connector is also capable of creating and altering the schema via DDL Statements such as CREATE LOCAL VIEW, ALTER LOCAL VIEW, and DROP LOCAL VIEW.

Create a View

To create a new view using DDL statements, provide the view name and query as follows:

CREATE LOCAL VIEW [MyViewName] AS SELECT * FROM Customers LIMIT 20;

If no JSON file exists, the above code creates one. The view is then created in the JSON configuration file and is now discoverable. The JSON file location is specified by the UserDefinedViews connection property.

Alter a View

To alter an existing view, provide the name of an existing view alongside the new query you would like to use instead:

ALTER LOCAL VIEW [MyViewName] AS SELECT * FROM Customers WHERE TimeModified > '3/1/2020';

The view is then updated in the JSON configuration file.

Drop a View

To drop an existing view, provide the name of an existing schema alongside the new query you would like to use instead.

DROP LOCAL VIEW [MyViewName]

This removes the view from the JSON configuration file. It can no longer be queried.

Schema for User Defined Views

User Defined Views are exposed in the UserViews schema by default. This is done to avoid the view's name clashing with an actual entity in the data model. You can change the name of the schema used for UserViews by setting the UserViewsSchemaName property.

Work with User Defined Views

For example, a SQL statement with a User Defined View called UserViews.RCustomers only lists customers in Raleigh:

SELECT * FROM Customers WHERE City = 'Raleigh';

An example of a query to the driver:

SELECT * FROM UserViews.RCustomers WHERE Status = 'Active';

Resulting in the effective query to the source:

SELECT * FROM Customers WHERE City = 'Raleigh' AND Status = 'Active';

That is a very simple example of a query to a User Defined View that is effectively a combination of the view query and the view definition. It is possible to compose these queries in much more complex patterns. All SQL operations are allowed in both queries and are combined when appropriate.

SSL Configuration

Customize the SSL Configuration

By default, the connector attempts to negotiate SSL/TLS by checking the server's certificate against the system's trusted certificate store.

To specify another certificate, see the SSLServerCert property for the available formats to do so.

Client SSL Certificates

The Presto connector also supports setting client certificates. Set the following to connect using a client certificate.

• SSLClientCert: The name of the certificate store for the client certificate.
• SSLClientCertType: The type of key store containing the TLS/SSL client certificate.
• SSLClientCertPassword: The password for the TLS/SSL client certificate.
• SSLClientCertSubject: The subject of the TLS/SSL client certificate.

Data Model

The Presto connector models the Presto REST APIs as relational tables and stored procedures that can be accessed with standard SQL. This enables access from standards-based tools.

The table definitions are dynamically retrieved. When you connect, the connector connects to Presto and gets the list of tables and the metadata for the tables by querying the Presto REST server. Any changes to the remote data are immediately reflected in your queries.

System Tables

You can query the system tables described in this section to access schema information, information on data source functionality, and batch operation statistics.

Schema Tables

The following tables return database metadata for Presto:

• sys_catalogs: Lists the available databases.
• sys_schemas: Lists the available schemas.
• sys_tables: Lists the available tables and views.
• sys_tablecolumns: Describes the columns of the available tables and views.
• sys_procedures: Describes the available stored procedures.
• sys_procedureparameters: Describes stored procedure parameters.
• sys_keycolumns: Describes the primary and foreign keys.
• sys_indexes: Describes the available indexes.

Data Source Tables

The following tables return information about how to connect to and query the data source:

• sys_connection_props: Returns information on the available connection properties.
• sys_sqlinfo: Describes the SELECT queries that the connector can offload to the data source.

Query Information Tables

The following table returns query statistics for data modification queries, including batch operations:

• sys_identity: Returns information about batch operations or single updates.

sys_catalogs

Lists the available databases.

The following query retrieves all databases determined by the connection string:

SELECT * FROM sys_catalogs

Columns

sys_schemas

Lists the available schemas.

The following query retrieves all available schemas:

SELECT * FROM sys_schemas

Columns

sys_tables

Lists the available tables.

The following query retrieves the available tables and views:

SELECT * FROM sys_tables

Columns

sys_tablecolumns

Describes the columns of the available tables and views.

The following query returns the columns and data types for the [Hive].[Default].Customers table:

SELECT ColumnName, DataTypeName FROM sys_tablecolumns WHERE TableName='Customers' AND CatalogName='Hive' AND SchemaName='Default'

Columns

sys_procedures

Lists the available stored procedures.

The following query retrieves the available stored procedures:

SELECT * FROM sys_procedures

Columns

sys_procedureparameters

Describes stored procedure parameters.

The following query returns information about all of the input parameters for the CreateTable stored procedure:

SELECT * FROM sys_procedureparameters WHERE ProcedureName='CreateTable' AND Direction=1 OR Direction=2

Columns

sys_keycolumns

Describes the primary and foreign keys.

The following query retrieves the primary key for the [Hive].[Default].Customers table:

SELECT * FROM sys_keycolumns WHERE IsKey='True' AND TableName='Customers' AND CatalogName='Hive' AND SchemaName='Default'

Columns

sys_foreignkeys

Describes the foreign keys.

The following query retrieves all foreign keys which refer to other tables:

SELECT * FROM sys_foreignkeys WHERE ForeignKeyType = 'FOREIGNKEY_TYPE_IMPORT'

Columns

sys_primarykeys

Describes the primary keys.

The following query retrieves the primary keys from all tables and views:

SELECT * FROM sys_primarykeys

Columns

sys_indexes

Describes the available indexes. By filtering on indexes, you can write more selective queries with faster query response times.

The following query retrieves all indexes that are not primary keys:

SELECT * FROM sys_indexes WHERE IsPrimary='false'

Columns

sys_connection_props

Returns information on the available connection properties and those set in the connection string.

When querying this table, the config connection string should be used:

jdbc:cdata:presto:config:

This connection string enables you to query this table without a valid connection.

The following query retrieves all connection properties that have been set in the connection string or set through a default value:

SELECT * FROM sys_connection_props WHERE Value <> ''

Columns

sys_sqlinfo

Describes the SELECT query processing that the connector can offload to the data source.

Discovering the Data Source's SELECT Capabilities

Below is an example data set of SQL capabilities. Some aspects of SELECT functionality are returned in a comma-separated list if supported; otherwise, the column contains NO.

The following query retrieves the operators that can be used in the WHERE clause:

SELECT * FROM sys_sqlinfo WHERE Name = 'SUPPORTED_OPERATORS'

Note that individual tables may have different limitations or requirements on the WHERE clause; refer to the Data Model section for more information.

Columns

sys_identity

Returns information about attempted modifications.

The following query retrieves the Ids of the modified rows in a batch operation:

SELECT * FROM sys_identity

Columns

sys_information

Describes the available system information.

The following query retrieves all columns:

SELECT * FROM sys_information

Columns

Advanced Configurations Properties

The advanced configurations properties are the various options that can be used to establish a connection. This section provides a complete list of the options you can configure. Click the links for further details.

Authentication

Kerberos

SSL

Schema

Miscellaneous

Authentication

This section provides a complete list of authentication properties you can configure.

AuthScheme

The scheme used for authentication. Accepted entries are None, Kerberos and LDAP. None is the default.

Possible Values

None, Kerberos, LDAP

Data Type

string

Default Value

None

Remarks

This field is used to authenticate against the server. Use the following options to select your authentication scheme:

• None: No authentication is performed, default.
• Kerberos: Set this to use Kerberos to authenticate.
• LDAP: Set this to use LDAP to authenticate.

Server

The host name or IP address of the Presto REST server.

Data Type

string

Default Value

""

Remarks

The host name or IP address of the Presto REST server.

Port

The port for the Presto REST server.

Data Type

string

Default Value

8080

Remarks

The port the Presto REST server is bound to.

User

The Presto user account used to authenticate.

Data Type

string

Default Value

""

Remarks

Together with Password, this field is used to authenticate against the Presto server.

Password

The password used to authenticate the user.

Data Type

string

Default Value

""

Remarks

The User and Password are together used to authenticate with the server.

PrestoKind

Indicates whether the connected instance is Trino or not.

Possible Values

Presto, Trino

Data Type

string

Default Value

Presto

Remarks

Indicates whether the connected instance is Trino or not.

UseSSL

Indicates whether SSL is enabled.

Data Type

bool

Default Value

false

Remarks

This field sets whether the connector will attempt to negotiate TLS/SSL connections to the server. By default, the connector checks the server's certificate against the system's trusted certificate store. To specify another certificate, set SSLServerCert.

Kerberos

This section provides a complete list of Kerberos properties you can configure.

KerberosKDC

The Kerberos Key Distribution Center (KDC) service used to authenticate the user.

Data Type

string

Default Value

""

Remarks

The Kerberos properties are used when using SPNEGO or Windows Authentication. The connector will request session tickets and temporary session keys from the Kerberos KDC service. The Kerberos KDC service is conventionally colocated with the domain controller.

If Kerberos KDC is not specified, the connector will attempt to detect these properties automatically from the following locations:

• KRB5 Config File (krb5.ini/krb5.conf): If the KRB5_CONFIG environment variable is set and the file exists, the connector will obtain the KDC from the specified file. Otherwise, it will attempt to read from the default MIT location based on the OS: C:\ProgramData\MIT\Kerberos5\krb5.ini (Windows) or /etc/krb5.conf (Linux).
• Java System Properties: Using the system properties java.security.krb5.realm and java.security.krb5.kdc.
• Domain Name and Host: If the Kerberos Realm and Kerberos KDC could not be inferred from another location, the connector will infer them from the configured domain name and host.

KerberosRealm

The Kerberos Realm used to authenticate the user.

Data Type

string

Default Value

""

Remarks

The Kerberos properties are used when using SPNEGO or Windows Authentication. The Kerberos Realm is used to authenticate the user with the Kerberos Key Distribution Service (KDC). The Kerberos Realm can be configured by an administrator to be any string, but conventionally it is based on the domain name.

If Kerberos Realm is not specified, the connector will attempt to detect these properties automatically from the following locations:

• KRB5 Config File (krb5.ini/krb5.conf): If the KRB5_CONFIG environment variable is set and the file exists, the connector will obtain the default realm from the specified file. Otherwise, it will attempt to read from the default MIT location based on the OS: C:\ProgramData\MIT\Kerberos5\krb5.ini (Windows) or /etc/krb5.conf (Linux)
• Java System Properties: Using the system properties java.security.krb5.realm and java.security.krb5.kdc.
• Domain Name and Host: If the Kerberos Realm and Kerberos KDC could not be inferred from another location, the connector will infer them from the user-configured domain name and host. This might work in some Windows environments.

KerberosSPN

The service principal name (SPN) for the Kerberos Domain Controller.

Data Type

string

Default Value

""

Remarks

If the SPN on the Kerberos Domain Controller is not the same as the URL that you are authenticating to, use this property to set the SPN.

KerberosKeytabFile

The Keytab file containing your pairs of Kerberos principals and encrypted keys.

Data Type

string

Default Value

""

Remarks

The Keytab file containing your pairs of Kerberos principals and encrypted keys.

KerberosServiceRealm

The Kerberos realm of the service.

Data Type

string

Default Value

""

Remarks

The KerberosServiceRealm is the specify the service Kerberos realm when using cross-realm Kerberos authentication.

In most cases, a single realm and KDC machine are used to perform the Kerberos authentication and this property is not required.

This property is available for complex setups where a different realm and KDC machine are used to obtain an authentication ticket (AS request) and a service ticket (TGS request).

KerberosServiceKDC

The Kerberos KDC of the service.

Data Type

string

Default Value

""

Remarks

The KerberosServiceKDC is used to specify the service Kerberos KDC when using cross-realm Kerberos authentication.

In most cases, a single realm and KDC machine are used to perform the Kerberos authentication and this property is not required.

This property is available for complex setups where a different realm and KDC machine are used to obtain an authentication ticket (AS request) and a service ticket (TGS request).

KerberosTicketCache

The full file path to an MIT Kerberos credential cache file.

Data Type

string

Default Value

""

Remarks

This property can be set if you wish to use a credential cache file that was created using the MIT Kerberos Ticket Manager or kinit command.

SSL

This section provides a complete list of SSL properties you can configure.

SSLClientCert

The TLS/SSL client certificate store for SSL Client Authentication (2-way SSL).

Data Type

string

Default Value

""

Remarks

The name of the certificate store for the client certificate.

The SSLClientCertType field specifies the type of the certificate store specified by SSLClientCert. If the store is password protected, specify the password in SSLClientCertPassword.

SSLClientCert is used in conjunction with the SSLClientCertSubject field in order to specify client certificates. If SSLClientCert has a value, and SSLClientCertSubject is set, a search for a certificate is initiated. See SSLClientCertSubject for more information.

Designations of certificate stores are platform-dependent.

The following are designations of the most common User and Machine certificate stores in Windows:

In Java, the certificate store normally is a file containing certificates and optional private keys.

When the certificate store type is PFXFile, this property must be set to the name of the file. When the type is PFXBlob, the property must be set to the binary contents of a PFX file (for example, PKCS12 certificate store).

SSLClientCertType

The type of key store containing the TLS/SSL client certificate.

Possible Values

USER, MACHINE, PFXFILE, PFXBLOB, JKSFILE, JKSBLOB, PEMKEY_FILE, PEMKEY_BLOB, PUBLIC_KEY_FILE, PUBLIC_KEY_BLOB, SSHPUBLIC_KEY_FILE, SSHPUBLIC_KEY_BLOB, P7BFILE, PPKFILE, XMLFILE, XMLBLOB

Data Type

string

Default Value

USER

Remarks

This property can take one of the following values:

SSLClientCertPassword

The password for the TLS/SSL client certificate.

Data Type

string

Default Value

""

Remarks

If the certificate store is of a type that requires a password, this property is used to specify that password to open the certificate store.

SSLClientCertSubject

The subject of the TLS/SSL client certificate.

Data Type

string

Default Value

*

Remarks

When loading a certificate the subject is used to locate the certificate in the store.

If an exact match is not found, the store is searched for subjects containing the value of the property. If a match is still not found, the property is set to an empty string, and no certificate is selected.

The special value "*" picks the first certificate in the certificate store.

The certificate subject is a comma separated list of distinguished name fields and values. For example, "CN=www.server.com, OU=test, C=US, E=support@company.com". The common fields and their meanings are shown below.

If a field value contains a comma, it must be quoted.

SSLServerCert

The certificate to be accepted from the server when connecting using TLS/SSL.

Data Type

string

Default Value

""

Remarks

If using a TLS/SSL connection, this property can be used to specify the TLS/SSL certificate to be accepted from the server. Any other certificate that is not trusted by the machine is rejected.

This property can take the following forms:

If not specified, any certificate trusted by the machine is accepted.

Certificates are validated as trusted by the machine based on the System's trust store. The trust store used is the 'javax.net.ssl.trustStore' value specified for the system. If no value is specified for this property, Java's default trust store is used (for example, JAVA_HOME\lib\security\cacerts).

Use '*' to signify to accept all certificates. Note that this is not recommended due to security concerns.

Schema

This section provides a complete list of schema properties you can configure.

Location

A path to the directory that contains the schema files defining tables, views, and stored procedures.

Data Type

string

Default Value

%APPDATA%\Presto Data Provider\Schema

Remarks

The path to a directory which contains the schema files for the connector (.rsd files for tables and views, .rsb files for stored procedures). The folder location can be a relative path from the location of the executable. The Location property is only needed if you want to customize definitions (for example, change a column name, ignore a column, and so on) or extend the data model with new tables, views, or stored procedures.

If left unspecified, the default location is "%APPDATA%\Presto Data Provider\Schema" with %APPDATA% being set to the user's configuration directory:

BrowsableSchemas

This property restricts the schemas reported to a subset of the available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC.

Data Type

string

Default Value

""

Remarks

Listing the schemas from databases can be expensive. Providing a list of schemas in the connection string improves the performance.

Tables

This property restricts the tables reported to a subset of the available tables. For example, Tables=TableA,TableB,TableC.

Data Type

string

Default Value

""

Remarks

Listing the tables from some databases can be expensive. Providing a list of tables in the connection string improves the performance of the connector.

This property can also be used as an alternative to automatically listing views if you already know which ones you want to work with and there would otherwise be too many to work with.

Specify the tables you want in a comma-separated list. Each table should be a valid SQL identifier with any special characters escaped using square brackets, double-quotes or backticks. For example, Tables=TableA,[TableB/WithSlash],WithCatalog.WithSchema.`TableC With Space`.

Note that when connecting to a data source with multiple schemas or catalogs, you will need to provide the fully qualified name of the table in this property, as in the last example here, to avoid ambiguity between tables that exist in multiple catalogs or schemas.

Views

Restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC.

Data Type

string

Default Value

""

Remarks

Listing the views from some databases can be expensive. Providing a list of views in the connection string improves the performance of the connector.

This property can also be used as an alternative to automatically listing views if you already know which ones you want to work with and there would otherwise be too many to work with.

Specify the views you want in a comma-separated list. Each view should be a valid SQL identifier with any special characters escaped using square brackets, double-quotes or backticks. For example, Views=ViewA,[ViewB/WithSlash],WithCatalog.WithSchema.`ViewC With Space`.

Note that when connecting to a data source with multiple schemas or catalogs, you will need to provide the fully qualified name of the table in this property, as in the last example here, to avoid ambiguity between tables that exist in multiple catalogs or schemas.

Catalog

The name of the catalog to use.

Data Type

string

Default Value

""

Remarks

This field allows you to limit the Catalog to the one explicitly specified. If not set, the connector will retrieve the available catalogs from the Presto server.

Schema

The schema of the Presto database.

Data Type

string

Default Value

""

Remarks

The schema of the Presto database.

Miscellaneous

This section provides a complete list of miscellaneous properties you can configure.

SessionProperties

Session properties to set for the system and for catalogs, specified as a list of key-value pairs and split with the comma. For example, abc=xyz,example.foo=bar sets the system property abc to the value xyz and the foo property for catalog example to the value bar.

Data Type

string

Default Value

""

Remarks

Session properties to set for the system and for catalogs, specified as a list of key-value pairs and split with the comma. For example, abc=xyz,example.foo=bar sets the system property abc to the value xyz and the foo property for catalog example to the value bar.

MaxRows

Limits the number of rows returned when no aggregation or GROUP BY is used in the query. This takes precedence over LIMIT clauses.

Data Type

int

Default Value

-1

Remarks

Limits the number of rows returned when no aggregation or GROUP BY is used in the query. This takes precedence over LIMIT clauses.

Other

These hidden properties are used only in specific use cases.

Data Type

string

Default Value

""

Remarks

The properties listed below are available for specific use cases. Normal driver use cases and functionality should not require these properties.

Specify multiple properties in a semicolon-separated list.

Integration and Formatting

PseudoColumns

This property indicates whether or not to include pseudo columns as columns to the table.

Data Type

string

Default Value

""

Remarks

This setting is particularly helpful in Entity Framework, which does not allow you to set a value for a pseudo column unless it is a table column. The value of this connection setting is of the format "Table1=Column1, Table1=Column2, Table2=Column3". You can use the "*" character to include all tables and all columns; for example, "*=*".

QueryPassthrough

This option passes the query to the Presto server as is.

Data Type

bool

Default Value

false

Remarks

When this is set, queries are passed through directly to Presto.

SortColumns

Indicates whether to sort columns alphabetically.

Data Type

bool

Default Value

true

Remarks

Indicates whether to sort columns alphabetically.

Timeout

The value in seconds until the timeout error is thrown, canceling the operation.

Data Type

int

Default Value

60

Remarks

If Timeout = 0, operations do not time out. The operations run until they complete successfully or until they encounter an error condition.

If Timeout expires and the operation is not yet complete, the connector throws an exception.

UserDefinedViews

A filepath pointing to the JSON configuration file containing your custom views.

Data Type

string

Default Value

""

Remarks

User Defined Views are defined in a JSON-formatted configuration file called UserDefinedViews.json. The connector automatically detects the views specified in this file.

You can also have multiple view definitions and control them using the UserDefinedViews connection property. When you use this property, only the specified views are seen by the connector.

This User Defined View configuration file is formatted as follows:

• Each root element defines the name of a view.
• Each root element contains a child element, called query, which contains the custom SQL query for the view.

For example:

{
    "MyView": {
        "query": "SELECT * FROM [Hive].[Default].Customers WHERE MyColumn = 'value'"
    },
    "MyView2": {
        "query": "SELECT * FROM MyTable WHERE Id IN (1,2,3)"
    }
}

Use the UserDefinedViews connection property to specify the location of your JSON configuration file. For example:

"UserDefinedViews", C:\Users\yourusername\Desktop\tmp\UserDefinedViews.json

Note that the specified path is not embedded in quotation marks.