Sybase 15.0 提供的優化profile/ optimization goal

Sybase 15.0 提供的優化profile

Ref:

http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.infocenter.dc00743.1502/html/queryprocessing/BGBJEDCE.htm

http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.dc00743_1500/html/qp_abstrpln/qp_abstrpln154.htm

如何調整

At Server level:

sp_configure "optimization goal", 0, "fastfirstrow"

At Session level:

set plan optgoal allrows_oltp

At the query level:

select * from A order by A.a plan "(use optgoal allrows_oltp)"

or

select * from A order by A.a plan "(use optgoal fastfirstrow 5)"

Table 7-3: Default settings for optimization criteria
Optimization criteria	fastfirstrow	allrows_oltp	allrows_mixed	allrows_dss
append_union_all	1	1	1	1
bushy_search_space	0	0	0	1
distinct_sorted	1	1	1	1
distinct_sorting	1	1	1	1
group_hashing	1	1	1	1
group_sorted	1	1	1	1
hash_join	0	0	0	1
hash_union_distinct	1	1	1	1
index_intersection	0	0	0	1
merge_join	0	0	1	1
merge_union_all	1	1	1	1
multi_gt_store_ind	0	0	0	1
nl_join	1	1	1	1
opp_distinct_view	1	1	1	1
parallel_query	1	0	1	1
store_index	1	1	1	1