Neoview Query Guide (R2.3, R2.4, R2.5)

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The ORDERED_HASH_JOIN operator has two child operators. The description field for this

operator contains:

Data TypeToken DescriptionToken

integerA sequential number assigned to the fragment. 0 is always master

executor and 1 is reserved for the Explain plan. Numbers 2 to n will

be ESP or DAM fragments.

fragment_id

integerThe fragment_id for the parent fragment of the current fragment.

Value is (none) for master executor.

parent_frag

textmaster, ESP, or DAMfragment_type

textInner or natural joinjoin_type

textName of join method: hashjoin_method

text1 for Type1 or 2 for Type2, depending on parallel join algorithmparallel_join_type

expr(text)Expression of the join predicatehash_join_predicate

expr(text)List of values that cause the hash table to be rebuilt when values

change

reuse_comparison_values

expr(text)Expression of the join predicatejoin_predicate

expr(text)Expression of the WHERE clause that is not included in a

hash_join_predicate or one of the child scans

selection_predicates

The difference between join_predicate and hash_join_predicate tokens is that the former are the

non-equijoin predicates. The latter are equijoin predicates that are used to help build and probe

the hash table.

ORDERED_HASH_SEMI_JOIN Operator

The ORDERED_HASH_SEMI_JOIN operator returns the outer rows for all matches. This operator

differs from the HYBRID_HASH_SEMI_JOIN operator in that it preserves the order of the outer

table and does not overflow to disk. The reuse feature enables reuse of the hash table for

subsequent requests within the same query. This operator is chosen only if the inner table is

small enough to fit in memory.

Also see “HYBRID_HASH_JOIN Operator” (page 29).

The ORDERED_HASH_SEMI_JOIN operator has two child operators. The description field for

this operator contains: