SQL/MX 2.x Reference Manual (H06.04+)

SQL/MX Statements
HP NonStop SQL/MX Reference Manual—540440-003
2-36
CONTROL QUERY SHAPE Statement
query-shape-options IMPLICIT
{ SORT | EXCHANGE | EXCHANGE_AND_SORT }
makes SORT, EXCHANGE, or ENFORCER nodes in CONTROL QUERY SHAPE
optional.
IMPLICIT SORT
indicates that the optimizer can add sort nodes at any location between the
nodes forced in the shape statements. The shape statement can still contain
additional sort nodes, and the compiler will enforce such nodes. Note that
WITHOUT SORT does not mean that the statement or the generated plans are
free of sort nodes.
IMPLICIT EXCHANGE
indicates that the optimizer can add exchange nodes at any location between
the nodes forced in the shape statements. The shape statement can still
contain additional exchange nodes, and the compiler will enforce such nodes.
Note that WITHOUT EXCHANGE does not mean that the statement or the
generated plans are free of exchange nodes.
IMPLICIT EXCHANGE_AND_SORT
indicates that the optimizer can add enforcer nodes (exchanges or sorts) at
any location between the nodes forced in the shape statements. The shape
scan-option is:
TABLE table
| PATH {access-path | ANY}
| BLOCKS_PER_ACCESS value
| MDAM mdam-option,...
| MDAM_COLUMNS mdam-columns-option,...
mdam-option is:
OFF
| SYSTEM
| FORCED
mdam-columns-option is:
n
| SYSTEM
| ALL
| (density,...)
| SYSTEM (density,...)
| ALL (density,...)
density is:
SPARSE
| DENSE
| SYSTEM