Multi-User mode is required to execute this command. Execute the DEFRAG function using the following command format:
►►─ DEFRAG DBID=n ─┬─────────────────────────────────┬─┬──────────────┬───────►◄ └─ ,KEYID=n ─┬──────────────────┬─┘ └─ ,PERCENT=n ─┘ ├─ ,FIRSTKEY= ─ n ─┤ └─ ,LASTKEY= ─ n ──┘
Command
Invokes the DEFRAG function.
Required Keywords
Specify the name of the DBID that you want to use.
a valid DBID
(No default)
Optional Keywords
Specify the key ID that you want to use.
Note: A normal DEFRAG does not include this keyword. KEYID= is provided for special cases where past executions have been analyzed and results have shown that one KEYID (or more) does not derive benefits from the DEFRAG.
a valid key ID
(No default)
If you specify KEYID=, you can use FIRSTKEY= and/or LASTKEY= to limit DEFRAG to a segment of the specified key. We recommend you allow FIRSTKEY=/LASTKEY= to default. The DEFRAG function normally defaults to include the full specified key range from low values to high values. FIRSTKEY= overrides the default starting position while LASTKEY= overrides the default ending position, limiting what is processed by DEFRAG. If one keyword is specified and the other is not specified, a default value is selected for the missing keyword. Normal CA Datacom key lengths are from 1 through 180 bytes. The key value data entered for FIRSTKEY= and LASTKEY= can be from 0 (zero) through 59 bytes long. You only need to code the number of positions of the key value that are significant to you, but be aware that the value coded is left justified regardless of key field data type. The utility pads the low order or remaining positions of the key value with low values on FIRSTKEY= and high values on LASTKEY=. To DEFRAG the entire key in one step, specify neither FIRSTKEY= nor LASTKEY=. Alternately, you could specify FIRSTKEY=00 and/or LASTKEY=00 to cause processing to start at low values and end at high values. The length of zero indicates that the padded key values (low values and high values) are to be used.
The data is not edited or interpreted. Therefore, if the key value data you need to enter is in binary, you must set up the JCL using a hexadecimal mode display and enter the key value data in hexadecimal. This data can contain blanks, commas, and any other special characters. CA Datacom/DB cannot edit this data for syntax, so the control statement can look invalid, especially when it includes blanks or commas or key value data containing English words. For example, FIRSTKEY=12121212121212 means the length is 12, key value is 121212121212. Another example, FIRSTKEY=10FIRSTKEY10 means the length is 10, key value is FIRSTKEY10.
A 2-byte length (in a range of 00 through 59) followed by a character string of key value bytes (for the length specified) that represents the key value.
The starting/ending position of the full key range from low to high values.
PERCENT= defaults to 100, which means all DXX blocks that can be merged will be merged, that is, any block that is less than completely full is a merge candidate. PERCENT=0 (zero) is treated as PERCENT=100. Coding a value between 1 and 99 means you want to tune which DXX blocks qualify as a merge candidates. Each DXX block has its current populated percentage compared to the number specified. If it is less than the specified percent, it is a merge candidate.
Note: We recommend that you do not code a value for PERCENT= but allow it to default to 100.
0 thru 100, where specifying a zero is the same as specifying 100
100
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