SQLによるパフォーマンスの向上（左結合？）

Question

パフォーマンス上の問題により、以下のクエリはもう機能しません。私は左の結合がほとんどありません。

主な問題は、異なる値から最大値を取得するために、同じテーブルで3つの「MAX」を検索していることです。

これを最適化する方法はありますか？

SELECT B.BG_BUG_ID "Defect ID" , 
     BG_USER_TEMPLATE_16 "Status" , 
     BG_USER_TEMPLATE_12 "Priority" , 
     BG_USER_TEMPLATE_11 "Severity", 
     BG_DETECTION_DATE "Detectado em", 
     BG_USER_TEMPLATE_01 "Fase Detecção", 
     BG_USER_TEMPLATE_10 "Fornecedor", 
     BG_USER_TEMPLATE_18 "Area Responsavel", 
     BG_RESPONSIBLE "Assinado para", 
     BG_USER_TEMPLATE_09 "Sistema Correção", 
     BG_USER_TEMPLATE_17 "Ambiente", 
     BG_USER_TEMPLATE_19 "Causa Raiz", 
     c.rtt_Time "RTT time", 
     BG_CLOSING_DATE "Data de Fechamento", 
     BG_USER_17 "Data Alteração Status", 
     al_description "Caminho Test Plan", 
     BG_SUMMARY "Descrição Resumida", 
     B.Fixed_Time "Fixed time", 
     BG_DETECTED_BY "Detectado por", 
     BG_USER_TEMPLATE_15 "Motivo", 
     BG_USER_TEMPLATE_04 "Motivo Status Waiting", 
     BG_USER_01 "Pendente com", 
     A.reopen_Time "lAST REOPEN DATE", 
     BG_TARGET_RCYC "Target Cycle", 
     R_CYCLE.rcyc_name "Target Cycle", 
     REL_NAME "Target Release", 
     BG_TARGET_REL "Target Release" , 
     BG_USER_TEMPLATE_08 "Tipo", 
     BG_USER_TEMPLATE_07 "Tipo de Solicitação", 
     BG_USER_TEMPLATE_06 "Status da Solicitação", 
     BG_USER_04 "Contador Fixing", 
     BG_USER_26 /*Defect.Reaberturas Validas*/ "Contador Reopened", 
     BG_USER_TEMPLATE_20 "CTs Impactados", 
     BG_USER_20 "Data Prevista Correção", 
     BG_USER_23 "Macro Processo", 
     BG_USER_TEMPLATE_03 "Defeito Associado" 
FROM BUG B LEFT JOIN ALL_LISTS AL 
ON B.bg_subject = AL.al_item_id 
LEFT JOIN (SELECT bg_bug_id, max(au_time) reopen_Time 
    from 
     bug,audit_log, audit_properties 
    where AU_ENTITY_TYPE='BUG' 
    and au_entity_id=bg_bug_id 
    AND AP_ACTION_ID=au_ACTION_ID 
    AND AP_FIELD_NAME='BG_USER_TEMPLATE_16' 
    AND AP_NEW_VALUE='Reopened' 
    group by bg_bug_id) A 
ON A.BG_BUG_ID=B.BG_BUG_ID 
LEFT JOIN (SELECT bg_bug_id, max(au_time) fixed_time 
    from 
     bug,audit_log, audit_properties 
    where AU_ENTITY_TYPE='BUG' 
    and au_entity_id=bg_bug_id 
    AND AP_ACTION_ID=au_ACTION_ID 
    AND AP_FIELD_NAME='BG_USER_TEMPLATE_16' 
    AND AP_NEW_VALUE='Ready to Application' 
    group by bg_bug_id) B 
ON A.BG_BUG_ID=B.BG_BUG_ID 
LEFT JOIN (SELECT bg_bug_id, max(au_time) rtt_time 
    from 
     bug,audit_log, audit_properties 
    where AU_ENTITY_TYPE='BUG' 
    and au_entity_id=bg_bug_id 
    AND AP_ACTION_ID=au_ACTION_ID 
    AND AP_FIELD_NAME='BG_USER_TEMPLATE_16' 
    AND AP_NEW_VALUE='Ready to Test' 
    group by bg_bug_id) C 
ON A.BG_BUG_ID=B.BG_BUG_ID 
left join RELEASE_CYCLES R_CYCLE 
on b.BG_TARGET_RCYC = R_CYCLE.rcyc_id 
Where 1=1 
and BG_TARGET_RCYC= 1085 
Order by B.BG_BUG_ID 

Answer 1

事前に一時テーブルにサブクエリを入れてみてください。次に、一時テーブルに参加するだけですか？

Answer 2

これらの3つのサブクエリ/派生テーブルを下の1つのサブクエリに縮小することができるように見えます。私はあなたの結合構文を更新しないために叫ばれたくないですが、テーブルエイリアスがなければ、どの列が何に対応しているかを推測する気がしません。

select 
    bg_bug_id, 
    max(case when AP_NEW_VALUE = 'Reopened' then au_time end) reopen_Time, 
    max(case when AP_NEW_VALUE = 'Ready to Application' then au_time end) fixed_Time, 
    max(case when AP_NEW_VALUE = 'Ready to Test' then au_time end) rtt_Time, 
from bug, audit_log, audit_properties 
where 
    au_entity_id = bg_bug_id AND AP_ACTION_ID = au_ACTION_ID /* join conditions */ 
    AND AU_ENTITY_TYPE = 'BUG' AND AP_FIELD_NAME = 'BG_USER_TEMPLATE_16' 
    AND AP_NEW_VALUE IN 
     ('Reopened', 'Ready to Application', 'Ready to Test') /* not really necessary? */ 
group by bg_bug_id 

ここでのトリックは凝集体のそれぞれの適切な値を除外するcase式を使用しています。

from 
    bug b 
    inner join audit_log l on l.au_entity = b.bg_bug_id 
    inner join audit_properties p on p.ap_action_id = l.au_action_id