Adding a Connection to HDFS

To add a connection to HDFS:

1. In the application console, navigate to the Connections page.
2. At the Add Connections panel, select the icon for the connection you want to add.
3. If the HDFS icon is not available, click the Add More icon to download and install the HDFS connector from the CData site.

For required properties, see the Settings tab.

For connection properties that are not typically required, see the Advanced tab.

Connecting to HDFS

In order to connect, set the following connection properties:

• Host: Set this value to the host of your HDFS installation.
• Port: Set this value to the port of your HDFS installation. Default port: 50070
• UseSSL: (Optional) Set this value to 'True', to negotiate TLS/SSL connections to the HDFS server. Default: 'False'.

Authenticating to HDFS

There are two authentication methods available for connecting to the HDFS data source, Anonymous Authentication and Negotiate (Kerberos) Authentication.

Anonymous Authentication

In some situations, HDFS may be connected to without any authentication connection properties. To do so, set the AuthScheme to None (default).

Kerberos

When authentication credentials are required, you can use Kerberos. See Using Kerberos for details on how to authenticate with Kerberos.

Fine Tuning Data Access

You can use the following properties to gain more control over the data returned from HDFS:

• DirectoryRetrievalDepth: How many subfolders to be recursively scanned before stopping.
  -1 specifies that all subfolders are scanned. 0 specifies that only the current folder will be scanned for items.
• Path: Limit the subfolders recursively scanned.

Kerberos

To authenticate to HDFS with Kerberos, set AuthScheme to NEGOTIATE.

Authenticating to HDFS 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 Sync App 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 Kerberos 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 Sync App uses the cache file to obtain the Kerberos ticket to connect to HDFS.

Note: If you would prefer not to edit KRB5CCNAME, you can use the KerberosTicketCache property to set the file path manually. After this is set, the Sync App uses the specified cache file to obtain the Kerberos ticket to connect to HDFS.

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 HDFS.

Enabling 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.

This section details a selection of advanced features of the HDFS Sync App.

User Defined Views

The Sync App supports the use of user defined views, virtual tables whose contents are decided by a pre-configured user defined query. These views are useful when you cannot directly control queries being issued to the drivers. For an overview of creating and configuring custom views, see User Defined Views .

SSL Configuration

Use SSL Configuration to adjust how Sync App handles TLS/SSL certificate negotiations. You can choose from various certificate formats;. For further information, see the SSLServerCert property under "Connection String Options" .

Firewall and Proxy

Configure the Sync App for compliance with Firewall and Proxy, including Windows proxies and HTTP proxies. You can also set up tunnel connections.

Query Processing

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

For further information, see Query Processing.

Logging

For an overview of configuration settings that can be used to refine CData logging, see Logging. Only two connection properties are required for basic logging, but there are numerous features that support more refined logging, which enables you to use the LogModules connection property to specify subsets of information to be logged.

Customizing the SSL Configuration

To enable TLS, set UseSSL to True.

With this configuration, the Sync App attempts to negotiate TLS with the server. The server certificate is validated against the default system trusted certificate store. You can override how the certificate gets validated using the SSLServerCert connection property.

To specify another certificate, see the SSLServerCert connection property.

Connecting Through a Firewall or Proxy

HTTP Proxies

To authenticate to an HTTP proxy, set the following:

• ProxyServer: the hostname or IP address of the proxy server that you want to route HTTP traffic through.
• ProxyPort: the TCP port that the proxy server is running on.
• ProxyAuthScheme: the authentication method the Sync App uses when authenticating to the proxy server.
• ProxyUser: the username of a user account registered with the proxy server.
• ProxyPassword: the password associated with the ProxyUser.

Other Proxies

Set the following properties:

• To use a proxy-based firewall, set FirewallType, FirewallServer, and FirewallPort.
• To tunnel the connection, set FirewallType to TUNNEL.
• To authenticate, specify FirewallUser and FirewallPassword.
• To authenticate to a SOCKS proxy, additionally set FirewallType to SOCKS5.

The CData Sync App models HDFS objects as relational tables and views. HDFS objects have relationships to other objects; in the tables, these relationships are expressed through foreign keys. The following sections show the available API objects and provide more information on executing SQL to HDFS APIs.

Schemas for most database objects are defined in simple, text-based configuration files.

Key Features

• The Sync App models HDFS entities such as files and permissions as relational views, allowing you to write SQL to query HDFS data.
• Stored procedures allow you to execute operations to HDFS
• Live connectivity to these objects means any changes to your HDFS account are immediately reflected when using the Sync App.

Views are similar to tables in the way that data is represented; however, views are read-only.

Queries can be executed against a view as if it were a normal table.

HDFS Connector for CData Sync Views

Name	Description
Files	Lists the contents of the supplied path.
Permissions	Lists the permissions of the files/file specified in the path.

Lists the contents of the supplied path.

Table Specific Information

Select

This will return a list of all the files and directories in your system. By default all subfolders are recursively scanned to list their children. You can configure the depth of subfolders you want to be recursively scanned with DirectoryRetrievalDepth property. All filters are executed client side within the Sync App.

Columns

Name	Type	Description
FileId [KEY]	Long	The unique Id associated with the file.
PathSuffix	String	The path suffix.
FullPath	String	The full path of the file.
Owner	String	The user who is the owner.
Group	String	The group owner.
Length	Long	The number of bytes in a file.
Permission	String	The permission represented as a octal string
Replication	Integer	The number of replication of a file.
StoragePolicy	Integer	The name of the storage policy
ChildrenNum	Integer	The number of children the file has.
BlockSize	Long	The block size of a file.
ModificationTime	Datetime	The modification time.
AccessTime	Datetime	The access time.
Type	String	The type of the path object.

Lists the permissions of the files/file specified in the path.

Table Specific Information

Select

This will return a list of permissions of all the files and directories in your system. All filters are executed client side within the Sync App.

Columns

Name	Type	Description
FullPath [KEY]	String	The full path of the file.
OwnerRead	Boolean	Whether the owner this file belongs to has read access.
OwnerWrite	Boolean	Whether the owner this file belongs to has write access.
OwnerExecute	Boolean	Whether the owner this file belongs to has execute access.
GroupRead	Boolean	Whether the group this file belongs to has read access.
GroupWrite	Boolean	Whether the group this file belongs to has write access.
GroupExecute	Boolean	Whether the group this file belongs to has execute access.
OthersRead	Boolean	Whether everyone else has read access.
OthersWrite	Boolean	Whether everyone else has write access.
OthersExecute	Boolean	Whether everyone else has execute access.

The connection string 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 in the connection string for this provider. Click the links for further details.

For more information on establishing a connection, see Establishing a Connection.

Authentication

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Property	Description
AuthScheme	The scheme used for authentication. Accepted entries are None, and Negotiate (Kerberos). None is the default.
Host	This property specifies the host of your HDFS installation.
Port	This property specifies the port of your HDFS installation.
User	The user name to login to the HDFS server.
Password	The password used to authenticate to the HDFS server. Only used when Kerberos authentication is selected.
AccessToken	The HDFS Access Token.
UseSSL	This field sets whether SSL is enabled.

Connection

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Property	Description
Path	This property specifies the HDFS path which will be used as the working directory.
DirectoryRetrievalDepth	Limit the subfolders recursively scanned.

Kerberos

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Property	Description
KerberosKDC	The Kerberos Key Distribution Center (KDC) service used to authenticate the user.
KerberosRealm	The Kerberos Realm used to authenticate the user.
KerberosSPN	The service principal name (SPN) for the Kerberos Domain Controller.
KerberosUser	The principal name for the Kerberos Domain Controller. Used in the format host/user@realm.
KerberosKeytabFile	The Keytab file containing your pairs of Kerberos principals and encrypted keys.
KerberosServiceRealm	The Kerberos realm of the service.
KerberosServiceKDC	The Kerberos KDC of the service.
KerberosTicketCache	The full file path to an MIT Kerberos credential cache file.

SSL

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Property	Description
SSLServerCert	Specifies the certificate to be accepted from the server when connecting using TLS/SSL.

Firewall

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Property	Description
FirewallType	Specifies the protocol the provider uses to tunnel traffic through a proxy-based firewall.
FirewallServer	Identifies the IP address, DNS name, or host name of a proxy used to traverse a firewall and relay user queries to network resources.
FirewallPort	Specifies the TCP port to be used for a proxy-based firewall.
FirewallUser	Identifies the user ID of the account authenticating to a proxy-based firewall.
FirewallPassword	Specifies the password of the user account authenticating to a proxy-based firewall.

Proxy

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Property	Description
ProxyAutoDetect	Specifies whether the provider checks your system proxy settings for existing proxy server configurations, rather than using a manually specified proxy server.
ProxyServer	The hostname or IP address of the proxy server that you want to route HTTP traffic through.
ProxyPort	The TCP port on your specified proxy server (set in the ProxyServer connection property) that has been reserved for routing HTTP traffic to and from the client.
ProxyAuthScheme	Specifies the authentication method the provider uses when authenticating to the proxy server specified in the ProxyServer connection property.
ProxyUser	The username of a user account registered with the proxy server specified in the ProxyServer connection property.
ProxyPassword	The password associated with the user specified in the ProxyUser connection property.
ProxySSLType	The SSL type to use when connecting to the proxy server specified in the ProxyServer connection property.
ProxyExceptions	A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the proxy server set in the ProxyServer connection property.

Logging

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Property	Description
LogModules	Specifies the core modules to include in the log file. Use a semicolon-separated list of module names. By default, all modules are logged.

Schema

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Property	Description
Location	Specifies the location of a directory containing schema files that define tables, views, and stored procedures. Depending on your service's requirements, this may be expressed as either an absolute path or a relative path.
BrowsableSchemas	Optional setting that restricts the schemas reported to a subset of all available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC .
Tables	Optional setting that restricts the tables reported to a subset of all available tables. For example, Tables=TableA,TableB,TableC .
Views	Optional setting that restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC .

Miscellaneous

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Property	Description
MaxRows	Specifies the maximum rows returned for queries without aggregation or GROUP BY.
Other	Specifies additional hidden properties for specific use cases. These are not required for typical provider functionality. Use a semicolon-separated list to define multiple properties.
PseudoColumns	Specifies the pseudocolumns to expose as table columns. Use the format 'TableName=ColumnName;TableName=ColumnName'. The default is an empty string, which disables this property.
Timeout	Specifies the maximum time, in seconds, that the provider waits for a server response before throwing a timeout error. The default is 60 seconds. Set to 0 to disable the timeout.
UserDefinedViews	Specifies a filepath to a JSON configuration file defining custom views. The provider automatically detects and uses the views specified in this file.

This section provides a complete list of the Authentication properties you can configure in the connection string for this provider.

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Property	Description
AuthScheme	The scheme used for authentication. Accepted entries are None, and Negotiate (Kerberos). None is the default.
Host	This property specifies the host of your HDFS installation.
Port	This property specifies the port of your HDFS installation.
User	The user name to login to the HDFS server.
Password	The password used to authenticate to the HDFS server. Only used when Kerberos authentication is selected.
AccessToken	The HDFS Access Token.
UseSSL	This field sets whether SSL is enabled.

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

Remarks

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

• None: Set this to use anonymous authentication and connect to the HDFS data source without specifying the user credentials.
• Negotiate: If AuthScheme is set to Negotiate, the Sync App will negotiate an authentication mechanism with the server. Set AuthScheme to Negotiate if you want to use Kerberos authentication.
• Token: Set this to authenticate using an AccessToken.

This property specifies the host of your HDFS installation.

Remarks

This property specifies the host of your HDFS installation.

This property specifies the port of your HDFS installation.

Remarks

This property specifies the port of your HDFS installation.

The user name to login to the HDFS server.

Remarks

The user name to login to the HDFS server. If AuthScheme=None, it is used as the authenticated user. If AuthScheme=Negotiate, it is used in the Kerberos Authentication as a client principal.

The password used to authenticate to the HDFS server. Only used when Kerberos authentication is selected.

Remarks

The password used to authenticate to the HDFS server. Only used when Kerberos authentication is selected.

The HDFS Access Token.

Remarks

The HDFS Access Token used to authenticate the requests.

This field sets whether SSL is enabled.

Remarks

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

This section provides a complete list of the Connection properties you can configure in the connection string for this provider.

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Property	Description
Path	This property specifies the HDFS path which will be used as the working directory.
DirectoryRetrievalDepth	Limit the subfolders recursively scanned.

This property specifies the HDFS path which will be used as the working directory.

Remarks

This property specifies the HDFS path which will be used as the working directory. Used in views Files and Permissions.

Limit the subfolders recursively scanned.

Remarks

DirectoryRetrievalDepth specifies how many subfolders will be recursively scanned before stopping. -1 specifies that all subfolders are scanned. 0 specifies that only the current folder will be scanned for items.

This section provides a complete list of the Kerberos properties you can configure in the connection string for this provider.

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Property	Description
KerberosKDC	The Kerberos Key Distribution Center (KDC) service used to authenticate the user.
KerberosRealm	The Kerberos Realm used to authenticate the user.
KerberosSPN	The service principal name (SPN) for the Kerberos Domain Controller.
KerberosUser	The principal name for the Kerberos Domain Controller. Used in the format host/user@realm.
KerberosKeytabFile	The Keytab file containing your pairs of Kerberos principals and encrypted keys.
KerberosServiceRealm	The Kerberos realm of the service.
KerberosServiceKDC	The Kerberos KDC of the service.
KerberosTicketCache	The full file path to an MIT Kerberos credential cache file.

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

Remarks

The Kerberos properties are used when using SPNEGO or Windows Authentication. The Sync App 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 Sync App 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 Sync App 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).
• Domain Name and Host: If the Kerberos Realm and Kerberos KDC could not be inferred from another location, the Sync App will infer them from the configured domain name and host.

The Kerberos Realm used to authenticate the user.

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 Sync App 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 Sync App 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)
• Domain Name and Host: If the Kerberos Realm and Kerberos KDC could not be inferred from another location, the Sync App will infer them from the user-configured domain name and host. This might work in some Windows environments.

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

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.

The principal name for the Kerberos Domain Controller. Used in the format host/user@realm.

Remarks

If the user you are using for the database doesn't match the user that is in the Kerberos database, this should be set to the Kerberos principal name.

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

Remarks

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

The Kerberos realm of the service.

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).

The Kerberos KDC of the service.

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).

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

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.

This section provides a complete list of the SSL properties you can configure in the connection string for this provider.

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Property	Description
SSLServerCert	Specifies the certificate to be accepted from the server when connecting using TLS/SSL.

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

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:

Description	Example
A full PEM Certificate (example shortened for brevity)	-----BEGIN CERTIFICATE----- MIIChTCCAe4CAQAwDQYJKoZIhv......Qw== -----END CERTIFICATE-----
A path to a local file containing the certificate	C:\cert.cer
The public key (example shortened for brevity)	-----BEGIN RSA PUBLIC KEY----- MIGfMA0GCSq......AQAB -----END RSA PUBLIC KEY-----
The MD5 Thumbprint (hex values can also be either space or colon separated)	ecadbdda5a1529c58a1e9e09828d70e4
The SHA1 Thumbprint (hex values can also be either space or colon separated)	34a929226ae0819f2ec14b4a3d904f801cbb150d

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

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

This section provides a complete list of the Firewall properties you can configure in the connection string for this provider.

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Property	Description
FirewallType	Specifies the protocol the provider uses to tunnel traffic through a proxy-based firewall.
FirewallServer	Identifies the IP address, DNS name, or host name of a proxy used to traverse a firewall and relay user queries to network resources.
FirewallPort	Specifies the TCP port to be used for a proxy-based firewall.
FirewallUser	Identifies the user ID of the account authenticating to a proxy-based firewall.
FirewallPassword	Specifies the password of the user account authenticating to a proxy-based firewall.

Specifies the protocol the provider uses to tunnel traffic through a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Note: By default, the Sync App connects to the system proxy. To disable this behavior and connect to one of the following proxy types, set ProxyAutoDetect to false.

The following table provides port number information for each of the supported protocols.

Protocol	Default Port	Description
TUNNEL	80	The port where the Sync App opens a connection to HDFS. Traffic flows back and forth via the proxy at this location.
SOCKS4	1080	The port where the Sync App opens a connection to HDFS. SOCKS 4 then passes theFirewallUser value to the proxy, which determines whether the connection request should be granted.
SOCKS5	1080	The port where the Sync App sends data to HDFS. If the SOCKS 5 proxy requires authentication, set FirewallUser and FirewallPassword to credentials the proxy recognizes.

To connect to HTTP proxies, use ProxyServer and ProxyPort. To authenticate to HTTP proxies, use ProxyAuthScheme, ProxyUser, and ProxyPassword.

Identifies the IP address, DNS name, or host name of a proxy used to traverse a firewall and relay user queries to network resources.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Specifies the TCP port to be used for a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Identifies the user ID of the account authenticating to a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

Specifies the password of the user account authenticating to a proxy-based firewall.

Remarks

A proxy-based firewall (or proxy firewall) is a network security device that acts as an intermediary between user requests and the resources they access. The proxy accepts the request of an authenticated user, tunnels through the firewall, and transmits the request to the appropriate server.

Because the proxy evaluates and transfers data backets on behalf of the requesting users, the users never connect directly with the servers, only with the proxy.

This section provides a complete list of the Proxy properties you can configure in the connection string for this provider.

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Property	Description
ProxyAutoDetect	Specifies whether the provider checks your system proxy settings for existing proxy server configurations, rather than using a manually specified proxy server.
ProxyServer	The hostname or IP address of the proxy server that you want to route HTTP traffic through.
ProxyPort	The TCP port on your specified proxy server (set in the ProxyServer connection property) that has been reserved for routing HTTP traffic to and from the client.
ProxyAuthScheme	Specifies the authentication method the provider uses when authenticating to the proxy server specified in the ProxyServer connection property.
ProxyUser	The username of a user account registered with the proxy server specified in the ProxyServer connection property.
ProxyPassword	The password associated with the user specified in the ProxyUser connection property.
ProxySSLType	The SSL type to use when connecting to the proxy server specified in the ProxyServer connection property.
ProxyExceptions	A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the proxy server set in the ProxyServer connection property.

Specifies whether the provider checks your system proxy settings for existing proxy server configurations, rather than using a manually specified proxy server.

Remarks

When this connection property is set to True, the Sync App checks your system proxy settings for existing proxy server configurations (no need to manually supply proxy server details).

This connection property takes precedence over other proxy settings. Set to False if you want to manually configure the Sync App to connect to a specific proxy server.

To connect to an HTTP proxy, see ProxyServer. For other proxies, such as SOCKS or tunneling, see FirewallType.

The hostname or IP address of the proxy server that you want to route HTTP traffic through.

Remarks

The Sync App only routes HTTP traffic through the proxy server specified in this connection property when ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead routes HTTP traffic through the proxy server specified in your system proxy settings.

The TCP port on your specified proxy server (set in the ProxyServer connection property) that has been reserved for routing HTTP traffic to and from the client.

Remarks

The Sync App only routes HTTP traffic through the proxy server port specified in this connection property when ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead routes HTTP traffic through the proxy server port specified in your system proxy settings.

For other proxy types, see FirewallType.

Specifies the authentication method the provider uses when authenticating to the proxy server specified in the ProxyServer connection property.

Remarks

The authentication type can be one of the following:

• BASIC: The Sync App performs HTTP BASIC authentication.
• DIGEST: The Sync App performs HTTP DIGEST authentication.
• NTLM: The Sync App retrieves an NTLM token.
• NEGOTIATE: The Sync App retrieves an NTLM or Kerberos token based on the applicable protocol for authentication.
• NONE: Set this when the ProxyServer does not require authentication.

For all values other than "NONE", you must also set the ProxyUser and ProxyPassword connection properties.

If you need to use another authentication type, such as SOCKS 5 authentication, see FirewallType.

The username of a user account registered with the proxy server specified in the ProxyServer connection property.

Remarks

The ProxyUser and ProxyPassword connection properties are used to connect and authenticate against the HTTP proxy specified in ProxyServer.

After selecting one of the available authentication types in ProxyAuthScheme, set this property as follows:

ProxyAuthScheme Value	Value to set for ProxyUser
BASIC	The user name of a user registered with the proxy server.
DIGEST	The user name of a user registered with the proxy server.
NEGOTIATE	The username of a Windows user who is a valid user in the domain or trusted domain that the proxy server is part of, in the format user@domain or domain\user.
NTLM	The username of a Windows user who is a valid user in the domain or trusted domain that the proxy server is part of, in the format user@domain or domain\user.
NONE	Do not set the ProxyPassword connection property.

The Sync App only uses this username if ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead uses the username specified in your system proxy settings.

The password associated with the user specified in the ProxyUser connection property.

Remarks

The ProxyUser and ProxyPassword connection properties are used to connect and authenticate against the HTTP proxy specified in ProxyServer.

After selecting one of the available authentication types in ProxyAuthScheme, set this property as follows:

ProxyAuthScheme Value	Value to set for ProxyPassword
BASIC	The password associated with the proxy server user specified in ProxyUser.
DIGEST	The password associated with the proxy server user specified in ProxyUser.
NEGOTIATE	The password associated with the Windows user account specified in ProxyUser.
NTLM	The password associated with the Windows user account specified in ProxyUser.
NONE	Do not set the ProxyPassword connection property.

For SOCKS 5 authentication or tunneling, see FirewallType.

The Sync App only uses this password if ProxyAutoDetect is set to False. If ProxyAutoDetect is set to True, which is the default, the Sync App instead uses the password specified in your system proxy settings.

The SSL type to use when connecting to the proxy server specified in the ProxyServer connection property.

Remarks

This property determines when to use SSL for the connection to the HTTP proxy specified by ProxyServer. You can set this connection property to the following values :

AUTO	Default setting. If ProxyServer is set to an HTTPS URL, the Sync App uses the TUNNEL option. If ProxyServer is set to an HTTP URL, the component uses the NEVER option.
ALWAYS	The connection is always SSL enabled.
NEVER	The connection is not SSL enabled.
TUNNEL	The connection is made through a tunneling proxy. The proxy server opens a connection to the remote host and traffic flows back and forth through the proxy.

A semicolon separated list of destination hostnames or IPs that are exempt from connecting through the proxy server set in the ProxyServer connection property.

Remarks

The ProxyServer is used for all addresses, except for addresses defined in this property. Use semicolons to separate entries.

Note that the Sync App uses the system proxy settings by default, without further configuration needed. If you want to explicitly configure proxy exceptions for this connection, set ProxyAutoDetect to False.

This section provides a complete list of the Logging properties you can configure in the connection string for this provider.

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Property	Description
LogModules	Specifies the core modules to include in the log file. Use a semicolon-separated list of module names. By default, all modules are logged.

Specifies the core modules to include in the log file. Use a semicolon-separated list of module names. By default, all modules are logged.

Remarks

This property lets you customize the log file content by specifying the logging modules to include. Logging modules categorize logged information into distinct areas, such as query execution, metadata, or SSL communication. Each module is represented by a four-character code, with some requiring a trailing space for three-letter names.

For example, EXEC logs query execution, and INFO logs general provider messages. To include multiple modules, separate their names with semicolons as follows: INFO;EXEC;SSL.

The Verbosity connection property takes precedence over the module-based filtering specified by this property. Only log entries that meet the verbosity level and belong to the specified modules are logged. Leave this property blank to include all available modules in the log file.

For a complete list of available modules and detailed guidance on configuring logging, refer to the Advanced Logging section in Logging.

This section provides a complete list of the Schema properties you can configure in the connection string for this provider.

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Property	Description
Location	Specifies the location of a directory containing schema files that define tables, views, and stored procedures. Depending on your service's requirements, this may be expressed as either an absolute path or a relative path.
BrowsableSchemas	Optional setting that restricts the schemas reported to a subset of all available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC .
Tables	Optional setting that restricts the tables reported to a subset of all available tables. For example, Tables=TableA,TableB,TableC .
Views	Optional setting that restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC .

Specifies the location of a directory containing schema files that define tables, views, and stored procedures. Depending on your service's requirements, this may be expressed as either an absolute path or a relative path.

Remarks

The Location property is only needed if you want to either customize definitions (for example, change a column name, ignore a column, etc.) or extend the data model with new tables, views, or stored procedures.

If left unspecified, the default location is %APPDATA%\\CData\\HDFS Data Provider\\Schema, where %APPDATA% is set to the user's configuration directory:

Platform	%APPDATA%
Windows	The value of the APPDATA environment variable
Linux	~/.config

Optional setting that restricts the schemas reported to a subset of all available schemas. For example, BrowsableSchemas=SchemaA,SchemaB,SchemaC .

Remarks

Listing all available database schemas can take extra time, thus degrading performance. Providing a list of schemas in the connection string saves time and improves performance.

Optional setting that restricts the tables reported to a subset of all available tables. For example, Tables=TableA,TableB,TableC .

Remarks

Listing all available tables from some databases can take extra time, thus degrading performance. Providing a list of tables in the connection string saves time and improves performance.

If there are lots of tables available and you already know which ones you want to work with, you can use this property to restrict your viewing to only those tables. To do this, 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: If you are connecting to a data source with multiple schemas or catalogs, you must specify each table you want to view by its fully qualified name. This avoids ambiguity between tables that may exist in multiple catalogs or schemas.

Optional setting that restricts the views reported to a subset of the available tables. For example, Views=ViewA,ViewB,ViewC .

Remarks

Listing all available views from some databases can take extra time, thus degrading performance. Providing a list of views in the connection string saves time and improves performance.

If there are lots of views available and you already know which ones you want to work with, you can use this property to restrict your viewing to only those views. To do this, 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: If you are connecting to a data source with multiple schemas or catalogs, you must specify each view you want to examine by its fully qualified name. This avoids ambiguity between views that may exist in multiple catalogs or schemas.

This section provides a complete list of the Miscellaneous properties you can configure in the connection string for this provider.

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Property	Description
MaxRows	Specifies the maximum rows returned for queries without aggregation or GROUP BY.
Other	Specifies additional hidden properties for specific use cases. These are not required for typical provider functionality. Use a semicolon-separated list to define multiple properties.
PseudoColumns	Specifies the pseudocolumns to expose as table columns. Use the format 'TableName=ColumnName;TableName=ColumnName'. The default is an empty string, which disables this property.
Timeout	Specifies the maximum time, in seconds, that the provider waits for a server response before throwing a timeout error. The default is 60 seconds. Set to 0 to disable the timeout.
UserDefinedViews	Specifies a filepath to a JSON configuration file defining custom views. The provider automatically detects and uses the views specified in this file.

Specifies the maximum rows returned for queries without aggregation or GROUP BY.

Remarks

This property sets an upper limit on the number of rows the Sync App returns for queries that do not include aggregation or GROUP BY clauses. This limit ensures that queries do not return excessively large result sets by default.

When a query includes a LIMIT clause, the value specified in the query takes precedence over the MaxRows setting. If MaxRows is set to "-1", no row limit is enforced unless a LIMIT clause is explicitly included in the query.

This property is useful for optimizing performance and preventing excessive resource consumption when executing queries that could otherwise return very large datasets.

Specifies additional hidden properties for specific use cases. These are not required for typical provider functionality. Use a semicolon-separated list to define multiple properties.

Remarks

This property allows advanced users to configure hidden properties for specialized scenarios. These settings are not required for normal use cases but can address unique requirements or provide additional functionality. Multiple properties can be defined in a semicolon-separated list.

Note: It is strongly recommended to set these properties only when advised by the support team to address specific scenarios or issues.

Specify multiple properties in a semicolon-separated list.

Integration and Formatting

DefaultColumnSize	Sets the default length of string fields when the data source does not provide column length in the metadata. The default value is 2000.
ConvertDateTimeToGMT	Determines whether to convert date-time values to GMT, instead of the local time of the machine.
RecordToFile=filename	Records the underlying socket data transfer to the specified file.

Specifies the pseudocolumns to expose as table columns. Use the format 'TableName=ColumnName;TableName=ColumnName'. The default is an empty string, which disables this property.

Remarks

This property allows you to define which pseudocolumns the Sync App exposes as table columns.

To specify individual pseudocolumns, use the following format: "Table1=Column1;Table1=Column2;Table2=Column3"

To include all pseudocolumns for all tables use: "*=*"

Specifies the maximum time, in seconds, that the provider waits for a server response before throwing a timeout error. The default is 60 seconds. Set to 0 to disable the timeout.

Remarks

This property controls the maximum time, in seconds, that the Sync App waits for an operation to complete before canceling it. If the timeout period expires before the operation finishes, the Sync App cancels the operation and throws an exception.

The timeout applies to each individual communication with the server rather than the entire query or operation. For example, a query could continue running beyond 60 seconds if each paging call completes within the timeout limit.

Setting this property to 0 disables the timeout, allowing operations to run indefinitely until they succeed or fail due to other conditions such as server-side timeouts, network interruptions, or resource limits on the server. Use this property cautiously to avoid long-running operations that could degrade performance or result in unresponsive behavior.

Specifies a filepath to a JSON configuration file defining custom views. The provider automatically detects and uses the views specified in this file.

Remarks

This property allows you to define and manage custom views through a JSON-formatted configuration file called UserDefinedViews.json. These views are automatically recognized by the Sync App and enable you to execute custom SQL queries as if they were standard database views. The JSON file defines each view as a root element with a child element called "query", which contains the SQL query for the view. For example:

{
	"MyView": {
		"query": "SELECT * FROM Files WHERE MyColumn = 'value'"
	},
	"MyView2": {
		"query": "SELECT * FROM MyTable WHERE Id IN (1,2,3)"
	}
}

You can define multiple views in a single file and specify the filepath using this property. For example: UserDefinedViews=C:\Path\To\UserDefinedViews.json. When you use this property, only the specified views are seen by the Sync App.

Refer to User Defined Views for more information.