SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
C-82
CONTROL TABLE Directive
OPEN { ALL | ACCESSED } [ PARTITIONS ]
specifies whether to defer opening indexes and remaining partitions in a table until
access to the objects is required:
The default is OPEN ACCESSED.
{ RETURN | WAIT } IF LOCKED
specifies action if you attempt to access data with STABLE or REPEATABLE
access and the data is locked by another user. (This option does not apply to
catalog tables.)
The default is WAIT IF LOCKED.
If you specify RETURN IF LOCKED, make sure the TIMEOUT option is large
enough to permit a lock request to be passed to the disk process.
You might want to use RETURN IF LOCKED for converted Enscribe applications
that used alternate locking mode. The operations are similar.
SEQUENTIAL [ INSERT | READ | UPDATE ] { ON | OFF | ENABLE }
specifies whether the file system should buffer INSERT, READ, or UPDATE
operations. Buffering reduces the number of messages between the file system
and disk process by a factor equal to the blocking factor.
For audited tables, the default is ENABLE. For nonaudited tables, the default is
OFF for INSERT and UPDATE; the default is ENABLE for READ.
Use OFF if operations will not be sequential or if a small but common subset of
rows will be accessed concurrently by more than one process. Use ENABLE if you
are unsure whether operations will be sequential or random.
Under certain conditions, SQL might determine whether or not to buffer operations
regardless of the option you specify. For more information about this and other
aspects of buffering, see the comments on buffered operations under
Considerations—CONTROL TABLE on page C-85.
ALL opens all indexes and partitions the first time any partition is
accessed
ACCESSED opens indexes and partitions only as needed (called “on-demand
opens”)
RETURN returns file-system error 73 (SQL error -8300) to SQLCI or
(through SQLCODE) the host language program.
WAIT waits for data as specified by the TIMEOUT option.
ON buffer operations when possible
OFF do not buffer operations
ENABLE let SQL decide when to buffer