Qualifying READS Requests
You can use qualifications to limit data returned by READS to the records you actually need.
You can use qualifications to limit data returned by READS to the records you actually need. Using qualifications is optional. If not used, information is obtained from all active allied threads and database access threads. Information is not obtained for any inactive database access threads that might exist. Refer to the Db2 mapping macro DSNDWQAL stored in the DSNxxx.SDSNMACS library which describes the qualification area.
RLX
/IFI uses REXX variables to receive qualification from your REXX program.The following trace records, identified by IFCID, cannot be qualified: 0001, 0002, 0106. If you attempt to qualify them, the qualification is ignored:. The rest of the synchronous records can be qualified.
The following table lists the variables that can be set to qualify trace requests:
Variable Name | Notes | Description |
WQALACE | 1,2 | 16 hexadecimal digits which represent the address of Agent Control Element used to identify the thread. |
WQALASID | 1,2 | 8 hexadecimal digits which specify the address Space ID (ASID) identifying process wanted |
WQALAUTH | 1,3 | 8-byte character field of the current primary authorization ID of the process wanted |
WQALCONN | 1,3 | 8-byte character field containing the connection name of the process wanted. If set, it must specify a valid connection name. |
WQALCORR | 1,3 | 24 hexadecimal digits or 12 characters that specify the correlation identifier of the process wanted |
WQALHASH | 1,2,4,5 | 8 hexadecimal digits which represent the hash value for a lock |
WQALLOCN | 1,3 | 16 character location name to select data for distributed agents originating at a specified location. |
WQALLUWI | 1,3 | 24 character Logical Unit of Work ID for the thread wanted |
WQALNETI | 1,3 | LUWID: Network ID -- 8-byte character data which is a part of the WQALLUWI field |
WQALUNM | 1,3 | LUWID: LUNAME -- 8-byte character Data that is a part of the WQALLUWI field |
WQALUNIQ | 1,3 | LUWID: Unique Value – 12-hexadecimal digits which is a part of the WQALLUWI |
WQALCCNT | 1,3 | LUWID: Commit counter - 4-hexadecimal digits which are part of the WQALLUWI |
WQALOPID | 1,6 | 8-byte character field containing the authorization ID for the thread wanted |
WQALPLAN | 1,3 | 8-byte character field containing the PLAN name of the process wanted |
WQALREST | 1,2,3,4,5 | 32-byte field (64 hexadecimal digits) which contains an IRLM resource token or 0 |
When specifying qualification values for hexadecimal fields, use character representations of hexadecimal digits. That is 0 - 9, and characters A - F.
RLX
/IFI does not translate or alter a hexadecimal field in any way.- If a variable is not defined or is set to NULL, the field is not used for qualification.
- Must contain only hexadecimal digits.
- Masking allowed for this field.
- Only valid when requesting IFCID 149.
- Value can be obtained from a previous IFCID 148 or 150.
EXAMPLES:
- To select a thread whose LUWID has a unique value of ‘AB59235A8F22’X, execute the following assignment statement:WQALUNIQ = ‘AB59235A8F22’.
- To select all threads containing the value ‘Db2LU1’ in the LUNAME field, execute the following assignment statement:WQALLUNM = ‘Db2LU1’.
Specifying Masks in Qualifications
Some of the qualification variables allow masks with the qualification value. You can use two masking characters in the qualifying variable: ‘_’ and ‘%’. The ‘_’ is a mask for any one-character byte, while the ‘%’ character matches any number of any characters. For example:
- To select all application threads whose plan names start with the character ‘R’, use the following mask:QWALPLAN = ‘R%’.
- To select all threads whose authorization ID has characters ‘SYS’ in positions 2,3, and 4, use the following mask:WQALAUTH = ‘_SYS%’.