SQL/MX 3.2.1 Query Guide (H06.26+, J06.15+)

SQL/MX Operators
HP NonStop SQL/MX Release 3.2.1 Query Guide—663851-003
7-86
UNIQUE_UPDATE Operator
The following is an example of the UNIQUE_DELETE operator:
prepare TestQuery26 from
delete from tt22 where f1=46;
DESCRIPTION
olt_optimization ....... used
olt_opt_lean ........... used
fragment_id ............ 2
parent_frag ............ 0
fragment_type .......... dp2
Scan_Direction ......... forward
olt_optimization ....... used
olt_opt_lean ........... used
iud_type ............... unique_delete DETCAT.DETSCH.TT22
lock_mode .............. not specified, defaulted to lock
cursor
access_mode ............ not specified, defaulted to read
committed
columns_retrieved ...... 2
key ..................... (F1 = %(46))
UNIQUE_UPDATE Operator
DAM Unique Group
The UNIQUE_UPDATE operator describes a portion of an execution plan that works
on one row only; it updates zero or one row.
The UNIQUE_UPDATE operator has no child nodes. The description field for this
operator contains the following:
olt_opt_lean Indicates for short, simple operations whether a
further optimization that reduces the physical
size of the plan is used. Its value is used or not
used.
text
iud_type Type of delete followed by table or index name. expr(text)
predicate Expression specified on WHERE clause that is
not reflected in the begin and end predicates.
expr(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 of the current
fragment. The value is (none) for the master
executor.
integer
fragment_type Master, ESP, or DP2. text
TP663851.fm Page 86 Wednesday, January 30, 2013 5:37 PM