NonStop SQL/MP Reference Manual

NonStop SQL/MP Reference Manual—142115
C-77
CONTROL TABLE Directive
sequence-number must be greater than zero and no greater than the number of
tables (or tables with different correlation names) participating in the SELECT. Two
tables (or two occurrences of the same table) cannot have the same join sequence in
a SELECT.
MDAM { OFF | ENABLE }
specifies whether to enable MDAM or turn it off.
You cannot specify MDAM OFF or MDAM ENABLE with the CONTROL TABLE
* command. The MDAM option must be associated with a specific table.
When you specify MDAM OFF or MDAM ENABLE, SQL sets the ACCESS PATH
MDAM options to their default values, USE DEFAULT KEY COLUMNS and
ACCESS SYSTEM.
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.
OFF turns MDAM off for the specified table
ENABLE enables the use of MDAM for the specified table. This is the default;
ENABLE has an effect only if you previously specified MDAM OFF or
ACCESS PATH...MDAM ON for the table.
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.