Adaptive Server lets you choose a query optimization goal that best suits your query environment:
fastfirstrow – optimizes queries so that Adaptive Server returns the first few rows as quickly as possible.
allrows_oltp – optimizes queries so that Adaptive Server uses a limited number of optimization criteria (described in “Optimization criteria”) to find a good query plan. allrows_oltp is most useful for purely OLTP queries.
allrows_mixed – optimizes queries so that Adaptive Server uses most available optimization techniques, including merge_join and parallel, to find the best query plan. allrows_mixed, which is the default strategy, is most useful in a mixed-query environment.
allrows_dss – optimizes queries so that Adaptive Server uses all available optimization techniques to find the best query plan, including hash join, advanced aggregates processing, and bushy tree plan. allrows_dss is most useful in a DSS environment.
