> # Default Behavior of Data Access Services

> When planning your SequeLink configuration, you may find it helpful to know the definition of the default (or newly created) data access service on Linux/UNIX/Windows, and z/OS so that you can decide whether the default definition fits your needs. If it does not, you can change the values of the service's attributes. The attributes can be modified using one of the SequeLink Manager tools. For instructions on using the SequeLink Manager, refer to the SequeLink Administrator's Guide.

> ### Default Behavior on Linux, UNIX, and Windows

> The following sections define the default behavior of the default SequeLink data access service on Linux/UNIX/Windows, and provide the name of the attribute that dictates the behavior. All attribute names are shown in parentheses. The attributes that begin with DataSource (for example, DataSourceReadOnly) are the attributes that define a server data source. For complete information about service attributes, see the SequeLink Administrator's Guide.

> ### Connection Model Default Behavior

> The connection model default is ThreadPool. (ServiceConnectionModel)

> The ThreadPool connection model default behavior is:

> - The number of prestarted threads in the thread pool is 8. (ServiceMinThreads)
> - The maximum number of threads to which the thread pool can increase to accommodate peak activity is 64. (ServiceMaxThreads)
> - The time allowed for thread-pool synchronization actions to take place before an internal error is generated is 60000 milliseconds. (ServiceInternalTimeout)
> - The idle time after which a thread allocated to a specific connection is released to the thread pool is 2000 milliseconds. (DataSourceThreadRpcTimeOut)
> - The maximum number of requests after which a thread allocated to a specific connection is released to the thread pool is 10. (DataSourceThreadMaxRpc)

> See "Planning Connection Models" for more information.

> ### Event Handling Default Behavior

> - The size of the event trace file is 1000000 bytes. (ServiceEventTraceSize)
> - The default location of the event trace file is the tracing subdirectory of the SequeLink Server installation directory. (ServiceEventTraceLocation)
> - On Windows, the default location is: \Program Files\DataDirect\SLServer60\tracing
> - On Linux/UNIX, the default location is:
>   /usr/slserver60/tracing
> - On z/OS, the default location is:
>   hlq.servicename.SWEVLOG.

> See "Planning Monitoring and Event Tracing" for more information.

> ### Security Default Behavior for Users

> The SequeLink Server accepts connections from all users, but only the users who can provide a valid DBMS user ID and password are allowed to access the database.

> The database connection accepts all types of SQL statements. Once connected to the database, the database security system guarantees that the user can only perform actions that are allowed by the database administrator. Messages (except for user IDs and passwords) sent between the client and the server are sent as cleartext. The service attributes are set as follows:

>     ServiceAuthMethods=anonymous
>     ServiceUser=everyone
>     DataSourceLogonMethod=DBMSLogon(UID,PWD)
>     DataSourceReadOnly=No
>     ServiceEncryptionAlgorithm=none

> See "Planning Security" for more information.

> Refer to the SequeLink Administrator's Guide for complete information about configuring SequeLink security.

> ### Security Default Behavior for Administrators

> Only the person who logs on using the administrator ID entered when the SequeLink Server software was installed is allowed to manage the SequeLink environment. The SequeLink Server Setup prompts for the SequeLink administrator's user ID when you install the SequeLink Server.

>     ServiceAdminAuthMethods=OSlogon(UID,PWD)
>     ServiceAdministrator=User_ID

> NOTE: On Windows, the SequeLink administrator must have administrator rights.

> See "Planning Security" for more information.

> Refer to the SequeLink Administrator's Guide for complete information about configuring SequeLink security.

> ### Debug Default Behavior

> Debugging is disabled. ("ServiceDebugLogLevel" and "ServiceDebugLogPath")

> Refer to the SequeLink Troubleshooting Guide and Reference for complete information about debugging.

> ### General Service Default Behavior

> - The service tries to recover from unexpected exceptions, rather than passing the exception to the operating system, which would result in a core dump. ("ServiceCatchExceptions")

> ### General Data Source Default Behavior

> - No schema names are specified to filter the result set returned by SQLTables and SQLProcedures (ODBC), getTables and getProcedures (JDBC), and TABLES and PROCEDURES (ADO). ("DataSourceSchemaFilterList")
> - No list of tables types is specified to filter the result set returned for SQLTables (ODBC), getTables (JDBC), and TABLES (ADO). ("DataSourceTableTypeFilterList")
> - The size of the buffer to use for array fetch is 65536 bytes. ("DataSourceArrayFetchMaxBytes")
> - The SequeLink Client can perform all supported SQL statements; the database connection is not read-only. (DataSourceReadOnly)
> - No default database catalog is used when connected to a SequeLink data access service. ("DataSourceCurrentCatalog")

> ### Internationalization Default Behavior

> The SequeLink administrator defines when SequeLink will support international code pages by selecting a service template with enhanced code page support. Support for international code pages is influenced by a combination of platform- and database-specific attributes.

> When using the standard service template, SequeLink supports ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16. The standard service template can also be used when the database code page maps to the client application code page. (ServiceCodePage=Default)

> The standard service template can also be used when the SequeLink Client transliterates character data from the code page that the SequeLink service is using to the code page of the client application or system. (ServiceCodePage=OS)

> When using the service template with enhanced code page support, SequeLink transliterates between the database code page and the application code page. See the default behavior section for each database for more information. (ServiceCodePage=Database)

> ### DB2 Service Default Behavior

> - The default database catalog is an empty string, which causes the ODBC Client and ADO Client to prompt for a valid DB2 database alias when connecting. ("DataSourceCurrentCatalog")
> - No DB2 connection options are set for the service. ("DataSourceDB2ConnectOptions")
> - Support for international characters depends on the service template used:
> - When using the standard DB2 service template, SequeLink supports standard ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16.
> - Using the service template with enhanced code page support, DB2 double byte character data types (graphics and dbclobs) are supported. ("ServiceCodePage")

> ### Informix Service Default Behavior

> - The default database catalog is an empty string, which causes the ODBC Client and ADO Client to prompt for a valid Informix database name. ("DataSourceCurrentCatalog")
> - A value for the Informix environment variable INFORMIXSERVER is set for the service. ("ServiceEnvironmentVariable" on Linux/UNIX, "DataSourceINFInformixServer" on Windows)
> - A value for the Informix environment variable INFORMIXDIR is set for the service. ("ServiceEnvironmentVariable" on Linux/UNIX, "DataSourceINFInformixDir" on Windows)
> - Informix delimited identifiers are enabled for the service. ("ServiceEnvironmentVariable" on Linux/UNIX, "DataSourceINFDelimldent" on Windows)
> - SequeLink uses the standard service template to support standard ASCII/EBCDIC transliteration. ("ServiceCodePage")

> ### Microsoft SQL Server Service Default Behavior

> - No default catalog is specified for use with Microsoft SQL Server when connecting to the database. ("DataSourceCurrentCatalog")
> - No warning is passed to the client application if Microsoft SQL Server encounters a problem opening server-side cursors. ("DataSourceMSSCursorWarnings").
> - The type of cursor used is specified using the "DataSourceMSSCursorType" attribute.
> - SequeLink Server uses a server-side cursor, which allows multiple concurrent statements (and cursors) to be active at the same time for each connection. ("DataSourceMSSCursorType")
> - Support for international characters depends on the service template used:
> - Using the standard SQL Server service template, SequeLink supports ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16. Unicode is not supported. ("ServiceCodePage")
> - Using the service template with enhanced code page support, data type support for international characters is influenced by a combination of service attributes. (ServiceCodePage)
> - With the enhanced code page template, SequeLink supports Unicode databases.

> ### Oracle Service Default Behavior

> - Synonyms of remote Oracle objects are not supported in catalog statements. ("DataSourceORASynDBLinkObjSupp")
> - All Oracle API calls that must be executed to establish a connection with the Oracle database will be serialized. ("ServiceORASerializeLogon")
> - Support for international characters depends on the service template used:
> - Using the standard Oracle service template, SequeLink supports ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16. Unicode data types are not supported. ("ServiceCodePage")
> - Using the service template with enhanced code page support, support for internationalization data types is influenced by ServiceCodePage=Database and by the environment variable NLS_LANG, which is set by default to AMERICAN_AMERICA.UTF8. ("ServiceCodePage")

> ### Sybase Service Default Behavior

> - A value for the Sybase network address (hostname, port) is set for the service. ("DataSourceSybNetworkAddress")
> - Parameter description requests are disabled. ("DataSourceDescribeParam")
> - Support for international characters depends on the service template used:
> - Using the standard Sybase service template, SequeLink supports ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16. Unicode data types are not supported. (ServiceCodePage)
> - Using the service template with enhanced code page support, data type support for international characters is influenced by ServiceCodePage=Database and by "DataSourceSybConnectOptions".

> ### ODBC Socket Service Default Behavior

> - The ODBC Socket service uses a connection string to make a connection to the back-end ODBC system data source for the database you want to access. The back-end ODBC driver can be a third-party driver or a DataDirect Connect for ODBC driver. ("DataSourceSOCODBCConnStr")
> - The name of the default file that contains the information returned from the OLE DB Provider_Types call by an ADO provider data source is swsoc.ini. ("DataSourceProviderTypesSection")
> - Support for international characters depends on the service template used:
> - Using the standard Socket Server service template, SequeLink supports ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16. Unicode data types are not supported.
> - Using the service templates with enhanced code page support for UTF-8 and UTF-16, support for Unicode data types depends on the back-end ODBC driver. ("ServiceCodePage")

> ### JDBC Socket Service Default Behavior

> - The JDBC Socket service uses the connection URL to make a connection to the back-end JDBC driver for the database you want to access. The back-end JDBC driver can be a third-party driver or a DataDirect Connect for JDBC driver. ("DataSourceSOCJDBCConnectionURL")
> - The name of the default file that contains the information returned from the OLE DB Provider_Types call by an ADO provider data source is swsoc.ini. ("DataSourceProviderTypesSection")
> - Using the standard Socket Server service template, SequeLink supports ASCII/EBCDIC transliteration for ODBC and ADO Clients. For JDBC and .NET Clients, SequeLink supports ASCII/EBCDIC conversion to UTF-16. Unicode data types are not supported. (ServiceCodePage)

> ### Default Behavior on z/OS

> The following sections define the default behavior of a SequeLink data access service on z/OS and provide the name of the attribute that dictates the behavior in parentheses. The attributes that begin with DataSource (for example, DataSourceReadOnly) are the attributes that define a server data source. For complete information about service attributes, refer to the SequeLink Administrator's Guide.

> #### Connection Model Default Behavior

> The ThreadPool connection model is the default. (ServiceConnectionModel)

> The ThreadPool connection model default behavior is:

> - The number of prestarted threads in the thread pool is 32. (ServiceMinThreads)
> - The maximum number of threads to which the thread pool can increase to accommodate peak activity is 64. ("ServiceMaxThreads")
> - The time allowed for thread-pool synchronization actions to take place before an internal error is generated is 60000 milliseconds. (ServiceInternalTimeout)
> - The idle time after which a thread allocated to a specific connection is released to the thread pool is 2000 milliseconds. ("DataSourceThreadRpcTimeOut")
> - The maximum number of requests after which a thread allocated to a specific connection is released to the thread pool is 50. ("DataSourceThreadMaxRpc")
> - The percentage of ServiceMaxThreads below which a connection is allowed to lock the thread for another DataSourceThreadRpcTimeOut period is 10. ("ServiceThreadLockThreshold")

> See "Planning Connection Models" for more information.

> #### Event Handling Default Behavior

> The size of the event trace file is 1000000 bytes. ("ServiceEventTraceSize")

> See "Planning Monitoring and Event Tracing" for more information.

> #### Security Default Behavior for Users

> The SequeLink Server accepts connections from all users. However, only users who can provide a valid operating system user ID and password are allowed to access the database. If the RACF TERMINAL class is not activated, the terminal ID is not verified.

> The database connection accepts all types of SQL statements. Once connected to the database, the database security system guarantees that the user can only perform actions that are allowed by the database administrator. Messages (except for user IDs and passwords) sent between the client and the server are sent as cleartext. The service attributes are set as follows:

>     MVSServiceAuthorizationEnable=FALSE
>     ServiceAuthMethods=OSLogon(UID,PWD,NWPD)
>     DataSourceLogonMethod=OSIntegrated
>     DataSourceReadOnly=No
>     ServiceEncryptionAlgorithm=none

> See "Planning Security" for more information.

> Refer to the SequeLink Administrator's Guide for complete information about configuring SequeLink security.

> #### Security Default Behavior for Administrators

> The SequeLink Server accepts connections from all users. Only users who can provide a valid operating system user ID and password are allowed to access the SequeLink Agent service, which means they can manage the SequeLink environment. If the RACF TERMINAL class is not activated, the terminal ID is not verified. The service attributes are set as follows:

>     MVSServiceAuthorizationEnable=FALSE
>     ServiceAdminAuthMethods=OSLogon(UID,PWD)

> See "Planning Security" for more information.

> Refer to the SequeLink Administrator's Guide for complete information about configuring SequeLink security.

> #### Internationalization Default Behavior

> Because the SequeLink Server for DB2 for z/OS is a Unicode service, no configuration is required. The ServiceCodePage attribute is defined by default and cannot be changed in the SequeLink Manager or Command Line interface.

> #### Debug Default Behavior

> Debugging is not enabled. ("ServiceDebugLogLevel" and "ServiceDebugLogPath")

> Refer to the SequeLink Troubleshooting Guide and Reference for complete information about debugging.

> #### General Service Default Behavior

> - The name of the service program is VAISTHRD and should not be modified, except on request of DataDirect technical support. (MVSServiceLoadModule)
> - The maximum number of concurrent sessions for a service is 2000. When this threshold is reached, the server refuses subsequent connection requests for the service. ("ServiceMaxSessions")
> - Workload Manager (WLM) support is not enabled. (MVSGlobalWLMEnclaves)

> Refer to the SequeLink Administrator's Guide for complete information about WLM.

> #### General Data Source Default Behavior

> - Server data sources have no name or description specified. (DataSourceName and "DataSourceDescription")
> - Transaction isolation levels are supported on connections. The default is Read Committed (cursor stability). ("DataSourceTransactionIsolation")
> - Cursors are not destroyed when the transaction is committed. ("DataSourceCursorHold")
> - No schema names are specified to filter the result set returned by SQLTables and SQLProcedures (ODBC), getTables and getProcedures (JDBC), and TABLES and PROCEDURES (ADO). ("DataSourceSchemaFilterList")
> - No list of table types is specified to filter the result set returned for SQLTables (ODBC), getTables (JDBC), and TABLES (ADO). ("DataSourceTableTypeFilterList")
> - The SequeLink Client can perform all supported SQL statements; the database connection is not read-only. ("DataSourceReadOnly")
> - No default database catalog is used when connected to a SequeLink data access service. ("DataSourceCurrentCatalog")