SQL/MX 2.x Query Guide (H06.04+, J06.03+)

SQL/MX Operators
HP NonStop SQL/MX Query Guide—540437-005
7-15
EXPLAIN_CMD Operator
EXPLAIN_CMD Operator
The EXPLAIN_CMD operator is generated when the EXPLAIN statement is used and it
has no children. The description field for this operator contains:
The example for EXPLAIN_CMD Operator is based on:
prepare TestQuery29 from
EXPLAIN options 'e' TestQuery28;
DESCRIPTION
fragment_id ............ 0
parent_frag ............ (none)
fragment_type ............ master
FILE_SCAN Operator
DAM Subset Group
The FILE_SCAN operator contains details about how a certain access path is scanned,
such as lock_mode and scan_direction.
The FILE_SCAN operator has no child nodes. The description field for this operator
contains:
Token Followed by ... Data Type
fragment_id A sequential number assigned to the fragment.
0 is always the master executor and 1 is
reserved for the EXPLAIN plan. Numbers 2 to n
will be ESP or DAM fragments.
integer
parent_frag The fragment_id for the parent fragment of the
current fragment. The value is (none) for the
master executor.
integer
fragment_type Master, ESP, or DP2. text
Token Followed by ... Data Type
fragment_id A sequential number assigned to the fragment.
0 is always the master executor and 1 is
reserved for the EXPLAIN plan. Numbers 2 to n
will be ESP or DAM fragments.
integer
parent_frag The fragment_id for the parent fragment of the
current fragment. The value is (none) for the
master executor.
integer
fragment_type Master, ESP, or DP2. text
olt_optimization Indicates whether an optimization for short,
simple operations is used. Its value is used or
not used.
text