SQL/MX 3.x Query Guide (H06.22+, J06.11+)

SQL/MX Operators
HP NonStop SQL/MX Query Guide—640323-001
7-28
INDEX_SCAN Operator
The following is an example of the INDEX_SCAN operator:
control query default nested_joins 'off';
control query default hash_joins 'off';
prepare TestQuery37b from
SELECT *
FROM customer LEFT JOIN nation ON c_nationkey = n_nationkey
WHERE c_custkey > 1000 AND c_custkey < 1010
ORDER BY c_custkey;
DESCRIPTION
fragment_id ............ 2
parent_frag ............ 0
fragment_type .......... dp2
olt_optimization ....... not used
olt_opt_lean ........... not used
scan_type .............. subset scan of index
DETCAT.DETSCH.CX1(DETCAT.DETSCH.CUSTOMER)
scan_direction ......... forward
key_type ............... simple
lock_mode .............. not specified, defaulted to lock
cursor
access_mode ............ not specified, defaulted to read
committed
columns_retrieved ...... 3
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
key_type Simple or MDAM. text
executor_predicates Any predicate expression that is not a key
predicate evaluated by the executor in DAM.
expr(text)
columns_retrieved Estimated number of columns to be returned. integer
fast_replydata_move Indicates whether an optimization for returning
data from DAM is used. The value used is
returned if this optimization is used.
text
fast_scan Indicates whether an optimization for a simple
scan operation is used. The value used is
returned if this optimization is used.
text
part_key_predicate Predicate expression specified on the
partitioning key. Displayed only if partitioning key
differs from clustering key.
expr(text)
mdam_disjunct Disjunct key predicates used by MDAM. expr(text)
Token Followed by ... Data Type