On Sun, Jul 26, 2009 at 1:02 AM, Greg Caulton <caultonpos@xxxxxxxxx> wrote:
Hello,
It seems to me that the following query should be a lot faster. This runs in 17 seconds (regardless how many times I run it)
select ac.* from application_controls_view ac, refs r where ac.custom_controller_ref_id = r.ref_id and r.ref_key like '%XYZ%';
if I do not use the view the query runs in under 100 ms
select ac.* from application_controls ac, refs r where ac.custom_controller_ref_id = r.ref_id and r.ref_key like '%XYZ%';
The view is
SELECT t.action_form_type_ref_id, r1.display AS action_form_type_display, t.action_order_type_ref_id, r2.display AS action_order_type_display, t.action_view_ref_id, r3.display AS action_view_display, t.active_ind, t.application_control_id, t.application_control_name, t.application_view_id, t.background_color, t.background_processing_ind, t.base_model_type_ref_id, r4.display AS base_model_type_display, t.base_value_script, t.class_instantiate_script, t.class_name, t.combo_add_to_list_ind, t.combo_category_ref_id, r5.display AS combo_category_display, t.combo_dynamic_search_ind, t.combo_filter_ref_id, r6.display AS combo_filter_display, t.combo_group_ref_id, r7.display AS combo_group_display, t.combo_short_display_ind, t.combo_values_term_id, t.comparison_operator_ref_id, r8.display AS comparison_operator_display, t.context_ref_id, r9.display AS context_display, t.control_description, t.control_format, t.control_format_ref_id, r10.display AS
<snip for brevity>
t.parameter_ref_id = r30.ref_id AND t.parameter_source_ref_id = r31.ref_id AND t.record_item_ref_id = r32.ref_id AND t.repeating_section_view_ref_id = r33.ref_id AND t.report_print_ref_id = r34.ref_id AND t.right_arrow_action_ref_id = r35.ref_id AND t.right_click_action_ref_id = r36.ref_id AND t.section_view_ref_id = r37.ref_id AND t.select_action_ref_id = r38.ref_id AND t.source_ref_id = r39.ref_id AND t.state_field_type_ref_id = r40.ref_id AND t.table_access_ref_id = r41.ref_id AND t.update_user_ref_id = r42.ref_id AND t.value_data_type_ref_id = r43.ref_id;
so basically it joins 43 times to the refs table on the primary key
the explain confirms the nested loops
" {NESTLOOP "
" :startup_cost 2660771.70 "
" :total_cost 3317979.85 "
" :plan_rows 27 "
" :plan_width 4708 "
" :targetlist ("
" {TARGETENTRY "
" :expr "
" {VAR "
" :varno 65001 "
" :varattno 29 "
" :vartype 20 "
" :vartypmod -1 "
" :varlevelsup 0 "
" :varnoold 5 "
<snip for brevity>
" -> Index Scan using refs_pk on refs r17 (cost=0.00..5.45 rows=1 width=50)"
" Index Cond: (r17.ref_id = t.detail_record_item_ref_id)"
" -> Index Scan using refs_pk on refs r1 (cost=0.00..5.45 rows=1 width=50)"
" Index Cond: (r1.ref_id = t.action_form_type_ref_id)"
" -> Index Scan using refs_pk on refs r (cost=0.00..5.45 rows=1 width=8)"
" Index Cond: (r.ref_id = t.custom_controller_ref_id)"
" Filter: ((r.ref_key)::text ~~ '%ERNEST%'::text)"
I did a vacuum analyze and so the primary key (indexes of course) is being used. But the above query is still 17s. If I dont return so many columns it comes down to around 10 seconds.
select ac.application_control_id from application_controls_view ac, refs r where ac.custom_controller_ref_id = r.ref_id and r.ref_key like '%ERNEST%';
But in either case this is only 37 rows. So 1554 lookups on a unique index on a table of 34000 rows means 6ms per internal join - note that many of those values are the same.
Does this seem right to you? Anything I can tune ?
--
Gregory Caulton
Principal at PatientOS Inc.
personal email: caultonpos@xxxxxxxxx
http://www.patientos.com
corporate: (888)-NBR-1EMR || fax 857.241.3022
Oh it seems to be the join that is throwing it off, because this runs in 600 ms
select ac.* from application_controls_view ac
where ac.application_control_id in (
50000745,
50000760,
50000759,
50000758,
50000757,
50000756,
50000753,
50000751,
50000750,
50000749,
50000748,
50000746,
50000744,
50001328,
50000752,
50000754,
50000755,
50002757,
50002756,
50002755,
50002754,
50001168,
50020825,
50021077,
50020821,
50020822,
50020824,
50020823,
50020820,
50020819,
50020809,
50020810,
50020806,
50020807,
50020817,
50021066,
50020808
)
never mind, makes sense now - its fixed
--
Gregory Caulton
Principal at PatientOS Inc.
personal email: caultonpos@xxxxxxxxx
http://www.patientos.com
corporate: (888)-NBR-1EMR || fax 857.241.3022
