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Use the UDBCTL command to open and initialize the data set. Whether the database will use the VSAM LSR pool depends on the options specified on the UDBCTL command.
By convention, the database name is the same as the DD name (z/OS) or file name (z/VM).
If you do not want the database to use the LSR pool, issue the following UDBCTL command:
UDBCTL OPEN=dbname ID=* STRNO=7 BUFNI=10 BUFND=10
The values for STRNO, BUFNI, and BUFND are the suggested defaults.
The STRNO value should be 3 + (value of NDBSUBMX SYSPARM - 1, times 2). A lower value can lead to string space being dynamically acquired by VSAM (z/OS) or string waits (z/VM) if several &NDBSCAN statements are executing concurrently.
If you want the database to use the LSR pool, issue the following UDBCTL command:
UDBCTL OPEN=dbname ID=* LSR
Use the LSRPOOL command to define the LSR buffer pool sizes and the number of buffers for each size. LSR is the recommended way of running an NDB.
You might want to use deferred I/O when running the NDB. Deferred I/O involves sharing of buffers in between requests and enhances performance but possibly at the expense of integrity. Deferred I/O is not recommended when running an NDB in an online transaction update environment.
If you want to run deferred I/O you must use the DEFER option of the UDBCTL command to open the file:
UDBCTL OPEN=dbname ID=* LSR DEFER
You must also use the DEFER option on the NDB START command. For more information about the NDB START command, see the Online Help.
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