我已經離開去調試一些我沒寫的hibernate代碼。我直言不諱地承認,我正努力讓自己的頭腦在Hibernate如何將查詢集中到這一點上,所以請耐心等待。如何調整Hibernate查詢
我們看到的問題是,Web應用程序花費了大量的時間來加載頁面(使用JSP,Spring和Hibernate)。
其中一個正在執行的查詢引用了一個映射中的公式,該映射似乎在執行hibernate的查詢中使用了兩次。第一個引用是列值,第二個引用用作內部聯接的標準。第二個,在內部聯接中,強制執行一個我們不需要的全表掃描,更不用說它讓查詢真的很慢。
有沒有辦法調整hibernate查詢,以便它不在查詢中使用此公式(列值除外)?請告知您是否需要更多信息。
編輯:每按照要求,這裏是我從登錄Hibernate獲取查詢:
SELECT this_.PARTY_ID AS PARTY1_23_2_,
this_.STUDENT_ID AS STUDENT3_23_2_,
this_.STUDENT_PIDM AS STUDENT4_23_2_,
this_.USERNAME AS USERNAME23_2_,
this_.FIRST_NAME AS FIRST6_23_2_,
this_.LAST_NAME AS LAST7_23_2_,
this_.ACTIVE AS ACTIVE23_2_,
subjectenr1_.PARTY_ID AS PARTY1_24_0_,
subjectenr1_.OFFERING_ID AS OFFERING2_24_0_,
subjectenr1_.RSTS_CODE AS RSTS3_24_0_,
subjectenr1_.SITE_CODE AS SITE4_24_0_,
subjectenr1_.PROGRAM_CODE AS PROGRAM5_24_0_,
(SELECT su2.offering_id
FROM sakaicfg.subject_offering su2
WHERE su2.offering_id = subjectenr1_.OFFERING_ID
) AS formula0_0_,
subjectoff2_.OFFERING_ID AS OFFERING1_25_1_,
subjectoff2_.CRN AS CRN25_1_,
subjectoff2_.IS_ACTIVE AS IS3_25_1_,
subjectoff2_.TEACHING_SCHOOL AS TEACHING4_25_1_,
subjectoff2_.CAMPUS AS CAMPUS25_1_,
subjectoff2_.START_SEMESTER AS START6_25_1_,
subjectoff2_.STUDYMODE AS STUDYMODE25_1_,
subjectoff2_.SUBJECT_ID AS SUBJECT8_25_1_,
subjectoff2_.GRADE_MARKING_CODE AS GRADE9_25_1_,
(SELECT MAX(su2.effective_semester)
FROM sakaicfg.subject su2
WHERE su2.subject_id = subjectoff2_.SUBJECT_ID
AND su2.effective_semester <= subjectoff2_.START_SEMESTER
) AS formula1_1_
FROM SAKAICFG.STUDENT this_
INNER JOIN SAKAICFG.SUBJECT_ENROLMENT subjectenr1_
ON this_.PARTY_ID=subjectenr1_.PARTY_ID
INNER JOIN SAKAICFG.SUBJECT_OFFERING subjectoff2_
ON (SELECT su2.offering_id
FROM sakaicfg.subject_offering su2
WHERE su2.offering_id = subjectenr1_.OFFERING_ID)=subjectoff2_.OFFERING_ID
WHERE this_.ACTIVE ='Y'
AND subjectenr1_.RSTS_CODE <>'DD'
AND subjectoff2_.IS_ACTIVE ='Y'
AND subjectoff2_.OFFERING_ID='35505'
ORDER BY this_.PARTY_ID DESC;
有問題的部分是摘錄:爲
(SELECT su2.offering_id
FROM sakaicfg.subject_offering su2
WHERE su2.offering_id = subjectenr1_.OFFERING_ID
)
映射xml文件Subject登記表包含以下關係:
<many-to-one name="student" entity-name="CsuActiveStudentDto" column="PARTY_ID" insert="false" update="false" access="field" unique="false"/>
<many-to-one name="subjectOffering" entity-name="CsuSubjectOfferingDto" insert="false" update="false" access="field" unique="false">
<formula>(select su2.offering_id
from sakaicfg.subject_offering su2 where su2.offering_id = OFFERING_ID)</formula>
</many-to-one>
<one-to-one name="student" class="au.edu.csu.enterprise.domain.StudentDto" property-ref="enrolment"/>
<many-to-one name="offering" class="au.edu.csu.enterprise.domain.SubjectOfferingDto" column="OFFERING_ID"/>
我一直在與我們的一位DBA一起研究查詢並隔離那些需要查看的查詢,這就是我們如何找到這一問題的方法。
如果你把一個例子,甚至真正的查詢可能有幫助,如果它是不要太長。 – 2011-04-18 05:39:00
Hib查詢可以像SQL一樣進行優化。因此你擁有的任務當然是可行的。但是你需要顯示代碼。 – 2011-04-18 05:42:01