-MODIFY DDF (DB2)

The MODIFY DDF command modifies information regarding the status and configuration of DDF, as well as statistical information regarding connections or threads controlled by DDF.

Authorization

To execute this command, you must use a privilege set of the process that includes one of the following privileges or authorities:

SYSOPR authority
SYSCTRL authority
SYSADM authority

DB2® commands that are issued from a logged-on z/OS® console or TSO SDSF can be checked by DB2 authorization using primary and secondary authorization IDs.

Syntax

>>-MODIFY DDF--------------------------------------------------->

>--+-ALIAS(alias-name)-+-ADD-------------------+-+-------------><
   |                   +-DELETE----------------+ |   
   |                   +-START-----------------+ |   
   |                   +-STOP------------------+ |   
   |                   +-CANCEL----------------+ |   
   |                   +-PORT(port-name)-------+ |   
   |                   +-SECPORT(secport-name)-+ |   
   |                   +-NPORT-----------------+ |   
   |                   +-NSECPORT--------------+ |   
   |                   +-IPV4(ipv4-address)----+ |   
   |                   +-IPV6(ipv6-address)----+ |   
   |                   +-NIPV4-----------------+ |   
   |                   '-NIPV6-----------------' |   
   |         .-BNDOPT--.                         |   
   '-PKGREL(-+-BNDPOOL-+-)-----------------------'   
             '-COMMIT--'

Option descriptions

ALIAS

Specifies the creation, changes to, or deletion of a specified location alias.

alias-name

Specifies the name of an alias for a DDF location. An alias is an alternative for the location name that can be used for connection processing. The alias name must meet all of the following requirements:

Contains no more than 16 characters.
Contains only letters (excluding alphabetic extenders), numbers, or the underscore character.

ADD

Creates a new alias with the specified name.

DELETE

Deletes the specified alias.

START

DB2 starts accepting connection requests to the specified alias if DDF is started. If DDF is not started, the alias is marked eligible for starting, and DB2 automatically starts accepting connection requests to the alias when DDF is started.

If the subsystem is part of a data sharing group, DB2 registers the alias with WLM and DB2 participates in sysplex workload balancing for connections to the alias.

STOP

DB2 stops accepting new connection requests to the specified alias. Existing database access threads that process connections to the alias remain unaffected. Inactive connections related to the alias are closed.

A stopped alias is marked ineligible for starting and does not start automatically when DDF starts. If the subsystem is part of a data sharing group, DB2 de-registers the alias with WLM and DB2 stops participating in sysplex workload balancing for connections to the alias.

CANCEL

DB2 stops accepting new connection requests to the specified alias. All database access threads that process connections to the alias are canceled and inactive connections related to the alias are closed.

A canceled alias is marked ineligible for starting and does not start automatically when DDF starts. If the subsystem is part of a data sharing group, DB2 de-registers the alias with WLM and DB2 stops participating in sysplex workload balancing for connections to the alias.

PORT(port-name)

Adds or replaces an existing port that can be used by DDF to accept distributed requests for the specified alias. The value specified for port-name value must be a decimal number between 1 and 65535, including 65535, and must be different than the values for the other specified ports. Specify a PORT value for an alias when you want to identify a subset of data sharing members to which a distributed request can go. End of change

SECPORT(secport-name)

Adds or replaces an existing secure port that can be used by DDF to accept secure distributed requests using SSL for the specified alias. The value specified for secport-name must be a decimal number between 1 and 65535, including 65535, and must be different than the values for the other specified ports. Specify a SECPORT value for an alias when you want to identify a subset of data sharing members to which a secure distributed request can go.

NPORT

Deletes the alias port, if one exists.

NSECPORT

Deletes the alias secure port, if one exists.

IPV4(IPv4-address)

Adds or replaces an existing member-specific IPv4 address. Clients use that address when they use one of the following capabilities for a connection to a dynamic location alias:

Sysplex workload balancing
XA protocols for coordinating distributed transactions

This address must be specified in the dotted decimal form.

IPV6(IPv6-address)

Adds or replaces an existing member-specific IPv6 address. Clients use that address when they use one of the following capabilities for a connection to a dynamic location alias:

Sysplex workload balancing
XA protocols for coordinating distributed transactions

This address must be specified in the colon hexadecimal form.

NIPV4

Deletes the alias IPv4 address, if one exists.

NIPV6

Deletes the alias IPv6 address, if one exists.

PKGREL

Specifies whether DB2 honors the bind options of packages that are used for remote client processing.

BNDOPT: The rules of the RELEASE bind option that was specified when the package was bound are applied to any package that is used for remote client processing. The high performance DBAT that is used by a terminating client connection is deallocated. BNDOPT is the default value of the MODIFY DDF PKGREL command.
BNDPOOL: The rules of the RELEASE bind option that was specified when the package was bound are applied to any package that is used for remote client processing. The high performance DBAT that is used by terminating a client connection is pooled.
COMMIT: The rules of the RELEASE(COMMIT) bind option are applied to any package that is used for remote client processing. COMMIT is the default value when the CMTSTAT subsystem parameter is set to ACTIVE. If the MODIFY DDF PKGREL command had never been issued, then COMMIT is the default value and the CMTSTAT subsystem parameter is set to INACTIVE.

Usage notes

Start of change When to use PKGREL options: You can specify that DDF uses the PKGREL(BNDOPT) or PKGREL(BNDPOOL) option during normal production operating hours. For environments where client configurations control the use of packages which were bound with the RELEASE(DEALLOCATE) bind option, BNDOPT may be the preferred value of the PKGREL option. For environments where any client is capable of using packages bound with the RELEASE(DEALLOCATE) bind option, BNDPOOL mightbe the preferred value of the PKGREL option. Either option value offers improved performance by reducing the CPU costs for allocation and deallocation of packages. However, packages that run under the rules of the RELEASE(DEALLOCATE) bind option are likely to remain allocated and prevent maintenance activities such as objects modifications and bind operations. Consequently, you can use the specify the PKGREL(COMMIT) option during routine and emergency maintenance periods. End of change

Delayed effects of PKGREL(COMMIT): When you issue the MODIFY DDF command and specify the PKGREL(COMMIT) option, the effects are not immediate. After the command is issued, any database access thread that was running RELEASE(DEALLOCATE) packages is terminated when the connection becomes inactive. At the next unit-of-work from the client, a new database access thread is created in RELEASE(COMMIT) mode. Any database access thread that remains active waiting for a new unit-of-work request from its client because of the rules of RELEASE(DEALLOCATE) is terminated by the DDF service task that runs every two minutes. Consequently, within approximately two minutes all database access threads run under the rules of the RELEASE(COMMIT) bind option.

Changes to alias attributes: The attributes of an existing alias can be modified only when the alias is stopped. The modified alias attributes take effect when the alias is started. By default, aliases created by the DSNJU003 utility are started and those created by the MODIFY DDF command are stopped. DSNJU004 does not print any information for aliases that are created by the MODIFY DDF command. You can use the output of the DISPLAY DDF command to find the status of a aliases created by the MODIFY DDF command.

Start of change How DB2 uses the IPV4 and IPV6 values: DB2 does not activate the IP addresses that you specify with the IPV4 or IPV6 parameters. Clients use those addresses for routing purposes only. DB2 does not require that the addresses are dynamic virtual IP addresses (DVIPAs). The IP addresses are used to reach the DVIPA network that serves the DB2 data sharing group. You can specify the IP addresses in the MODIFY DDF command only after the DSNJU003 is run with the IPV4 or IVP6 parameter to specify a member-specific location address. The specified IP addresses are returned in the WLM weighted server list when clients connect to a dynamic location alias, based on the following conditions: End of change

If the client connects using an IPv6 address, the server list contains the alias IP addresses that were specified with the IPV4 and IPV6 parameters of the MODIFY DDF command. If an IPv4 address was not specified in the MODIFY DDF command, the location IP address that was specified using the IPV4 keyword of the DSNJU003 utility is returned instead. Similarly, if an IPv6 address is not specified in the MODIFY DDF command, the location IP address that was specified using the IPV6 keyword of the DSNJU003 utility is returned instead.
If the client connects using an IPv4 address, the server list contains the alias IP address that was specified with the IPV4 parameter of the MODIFY DDF command. If an IPv4 address was not specified in the MODIFY DDF command, the location IP address that was specified using the IPV4 keyword of the DSNJU003 utility is returned instead.