SQL/MX 3.2 Query Guide (H06.25+, J06.14+)

SQL/MX Operators
HP NonStop SQL/MX Release 3.2 Query Guide—663851-002
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and does not overflow to disk. The reuse feature allows reuse of the hash table for
subsequent requests within the same query. Choose this operator when you need to
preserve the order of the outer table or if you can benefit from the reuse feature. It
should be chosen only if the inner table is small enough to fit in memory.
The ORDERED_HASH_ANTI_SEMI_JOIN operator has two child nodes. The
description field for this operator contains the following:
The following is an example of the ORDERED_HASH_ANTI_SEMI_JOIN operator:
PREPARE TestQuery3 FROM
SELECT s_nationkey, s_suppkey
FROM supplier
WHERE s_suppkey NOT IN
( SELECT ps_suppkey from partsupp)
GROUP BY s_nationkey, s_suppkey
ORDER BY s_nationkey, s_suppkey;
DESCRIPTION
fragment_id ............ 0
parent_frag ............ (none)
fragment_type .......... master
join_type .............. inner anti-semi
join_method ............ hash
hash_join_predicate .... (DETCAT.DETSCH.SX1.S_SUPPKEY =
DETCAT.DETSCH.PSX1.PS_SUPPKEY)
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
hash_join_predicate Expression of the join predicate. expr(text)
join_type Inner, left, natural, inner semi, or inner anti-
semi-join.
text
join_method Name of join method: hash text
join_predicate Expression of the join predicate. expr(text)
parallel_join_type Type1 or Type2, depending on parallel join
algorithm.
text
reuse_comparison_values List of values that cause the hash table to be
rebuilt when values change.
expr(text)
selection_predicates Expression of the WHERE clause. expr(text)
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