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
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SUBSET_UPDATE Operator
from CURSOR_UPDATE, which performs the read and update in separate operations.
The CURSOR_UPDATE operation also involves more messages.
This operator has no child nodes. The description field for this operator contains the
following:
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
begin_key Expression of the begin key predicates on the
clustering key columns of the table or index.
expr(text)
index_begin_key Expression of the begin key predicates on
index.
expr(text)
end_key Expression of the end key predicates on the
clustering key columns of the table or index.
expr(text)
index_end_key Expression of the end key predicates on index. expr(text)
check_constraint Check constraints in the update table. expr(text)
scan_type Physical scan associated with the scan logical
operator.
text
scan_direction Direction in which table is scanned: forward or
reverse.
text
lock_mode The lock mode specified: shared, exclusive, not
specified (defaulted to lock cursor), or unknown.
text
access_mode The access specified: read uncommitted, skip
conflict, read committed, stable, serializable,
mx serializable, not specified (defaulted to read
committed), or unknown.
text
new_rec_expr Computation of the row to be updated. expr(text)
columns_retrieved Estimate of the number of columns to be
returned.
integer
predicate Predicate used in the UPDATE statement. expr(text)
TP663851.fm Page 79 Wednesday, January 30, 2013 5:37 PM