Introduction I had a complex SQL query that was used to extract data from my system and send it across via web request to an external system. The query was taking unduly longer time to run. I made few changes to the query structure and reduced it run time to 7 mins. A part of the main query that was actually causing the delay has been pasted in the sections below. Problem Description One of my external systems reported that one of the queries that run at my end have failed with the error below: ORA-20001: Error - WebService Request Failed. ORA-29276: transfer timeout. When I tried running the SELECT query in question at my end (on Toad), the query kept running after I aborted it after almost 90 minutes. The central part of the original query is as below. This part was causing the entire query to slow down. The tables TEAM, TIMESHEET, TIMEENTRY and ASSIGNMENT are considerably huge tables with billions of records. The explain plan showed a full table access on ASSIGNMENT and TIMESHEET tables. The code Problem Code: SELECT TP.START STARTED , TP.FINISH FINISHED, TP.ID PERIOD, TM.PROJECTID PROJECTID, TM.ID TEAMID, TM.RESOURCEID RESOURCEID, SUM(TE.ACT) ACT FROMTASK TK, TEAM TM, ASSIGNMENT ASM, TIMEENTRY TE, PERIOD TP, (SELECTMAX(A.ID)ID,PERIODID,RESOURCEID FROM TIMESHEET A, PERIOD B WHERE STATUS IN(1,3,4)AND ADJUSTMENT =0 ANDA.periodid = B.id ANDTRUNC(B.START)>=TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUPBY PERIODID,RESOURCEID)TS WHERE TM.PROJECTID IN(SELECT PRJ.ID FROM PROJECTS PRJ, CU_PROJECT CU, PRJ_ASSOC AS, PRJ_UNITS OBS, PRJ_TYPES TYPE WHEREAS.TABLE_NAME ='PROJECTS' ANDAS.RECORD_ID = PRJ.ID ANDAS.UNIT_ID = OBS.ID AND OBS.TYPE_ID=TYPE.ID ANDTYPE.NAME='TEST1' AND CU.ID=PRJ.ID AND CU.PRT_CODE='TEST2') AND TK.PROJECTID=TM.PROJECTID AND ASM.TASKID=TK.ID AND ASM.RESOURCEID=TM.RESOURCEID AND TE.TIMESHEETID=TS.ID AND TS.PERIODID=TP.ID AND TE.ASSIGNID=ASM.ID ANDTRUNC(TP.START)>=TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUPBY TP.START,TM.ID,TM.RESOURCEID,TM.PROJECTID,TP.ID,TP.FINISH I changed the query structure as below. This query took 7 mins to run, a considerable improvement from the old query: Code: WITH TS AS(SELECT/*+ materialize */MAX(A.ID)ID,PERIODID,RESOURCEID FROM TIMESHEET A, PERIOD B WHERE STATUS IN(1,3,4)AND ADJUSTMENT =0 ANDA.periodid = B.id ANDTRUNC(B.START)>=TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUPBY PERIODID,RESOURCEID) SELECT TP.START STARTED , TP.FINISH FINISHED, TP.ID PERIOD, TM.PROJECTID PROJECTID, TM.ID TEAMID, TM.RESOURCEID RESOURCEID, SUM(TE.ACT) ACT FROMTASK TK, TEAM TM, ASSIGNMENT ASM, TIMEENTRY TE, PERIOD TP, (SELECT PRJ.ID FROM PROJECTS PRJ, CU_PROJECT CU, PRJ_ASSOC AS, PRJ_UNITS OBS, PRJ_TYPES TYPE WHEREAS.TABLE_NAME ='PROJECTS' ANDAS.RECORD_ID = PRJ.ID ANDAS.UNIT_ID = OBS.ID AND OBS.TYPE_ID=TYPE.ID ANDTYPE.NAME='TEST1' AND CU.ID=PRJ.ID AND CU.PRT_CODE='TEST2')S, WHERE TK.PROJECTID=TM.PROJECTID AND ASM.TASKID=TK.ID AND ASM.RESOURCEID=TM.RESOURCEID AND S.ID= TM.PROJECTID AND TE.TIMESHEETID=TS.ID AND TS.RESOURCEID = TM.RESOURCEID AND TS.PERIODID=TP.ID AND TE.ASSIGNID=ASM.ID AND TP.START>=TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUPBY TP.START,TM.ID,TM.RESOURCEID,TM.PROJECTID,TP.ID,TP.FINISH Using the WITH clause with materialize hint considerably improved the run time of the sub-query with a GROUP by clause. Moreover, the second sub-query which was joined in a WHERE clause earlier, was used as a table in the new query and this also helped increasing the performance. More readable code by Nimesh Code: SELECT TP.START STARTED , TP.FINISH FINISHED , TP.ID PERIOD , TM.PROJECTID PROJECTID , TM.ID TEAMID , TM.RESOURCEID RESOURCEID , SUM(TE.ACT) ACT FROM TASK TK , TEAM TM , ASSIGNMENT ASM , TIMEENTRY TE , PERIOD TP , (SELECT MAX(A.ID) ID , PERIODID , RESOURCEID FROM TIMESHEET A , PERIOD B WHERE STATUS IN (1,3,4) AND ADJUSTMENT = 0 AND A.periodid = B.id AND TRUNC(B.START) >= TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUP BY PERIODID , RESOURCEID ) TS WHERE TM.PROJECTID IN (SELECT PRJ.ID FROM PROJECTS PRJ , CU_PROJECT CU , PRJ_ASSOC AS , PRJ_UNITS OBS , PRJ_TYPES TYPE WHERE AS.TABLE_NAME = 'PROJECTS' AND AS.RECORD_ID = PRJ.ID AND AS.UNIT_ID = OBS.ID AND OBS.TYPE_ID=TYPE.ID AND TYPE.NAME='TEST1' AND CU.ID=PRJ.ID AND CU.PRT_CODE='TEST2' ) AND TK.PROJECTID = TM.PROJECTID AND ASM.TASKID = TK.ID AND ASM.RESOURCEID = TM.RESOURCEID AND TE.TIMESHEETID = TS.ID AND TS.PERIODID = TP.ID AND TE.ASSIGNID = ASM.ID AND TRUNC(TP.START) >= TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUP BY TP.START , TM.ID , TM.RESOURCEID , TM.PROJECTID , TP.ID , TP.FINISH Sameer
Yes and if you plan to do it for the current one email me the content in text file. You know my email which is shabbir @ this domain
I follow this kind of Indentation, which is little different from what other use And when writing the codes, use fixed with font so the indentation will appear properly. Code: SELECT TP.START STARTED , TP.FINISH FINISHED , TP.ID PERIOD , TM.PROJECTID PROJECTID , TM.ID TEAMID , TM.RESOURCEID RESOURCEID , SUM(TE.ACT) ACT FROM TASK TK , TEAM TM , ASSIGNMENT ASM , TIMEENTRY TE , PERIOD TP , (SELECT MAX(A.ID) ID , PERIODID , RESOURCEID FROM TIMESHEET A , PERIOD B WHERE STATUS IN (1,3,4) AND ADJUSTMENT = 0 AND A.periodid = B.id AND TRUNC(B.START) >= TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUP BY PERIODID , RESOURCEID ) TS WHERE TM.PROJECTID IN (SELECT PRJ.ID FROM PROJECTS PRJ , CU_PROJECT CU , PRJ_ASSOC AS , PRJ_UNITS OBS , PRJ_TYPES TYPE WHERE AS.TABLE_NAME = 'PROJECTS' AND AS.RECORD_ID = PRJ.ID AND AS.UNIT_ID = OBS.ID AND OBS.TYPE_ID=TYPE.ID AND TYPE.NAME='TEST1' AND CU.ID=PRJ.ID AND CU.PRT_CODE='TEST2' ) AND TK.PROJECTID = TM.PROJECTID AND ASM.TASKID = TK.ID AND ASM.RESOURCEID = TM.RESOURCEID AND TE.TIMESHEETID = TS.ID AND TS.PERIODID = TP.ID AND TE.ASSIGNID = ASM.ID AND TRUNC(TP.START) >= TRUNC(NEXT_DAY(NVL(NULL,SYSDATE)-28,'MONDAY')) GROUP BY TP.START , TM.ID , TM.RESOURCEID , TM.PROJECTID , TP.ID , TP.FINISH Did you use the same query exactly, as I found lot of syntactical errors? :crazy:
You can make some more changes (which I don't prefer ) like this, Code: SELECT PRJ.ID FROM PROJECTS PRJ , CU_PROJECT CU , PRJ_ASSOC AS , PRJ_UNITS OBS , PRJ_TYPES TYPE WHERE AS.TABLE_NAME = 'PROJECTS' AND AS.RECORD_ID = PRJ.ID AND AS.UNIT_ID = OBS.ID AND OBS.TYPE_ID = TYPE.ID AND TYPE.NAME = 'TEST1' AND CU.ID = PRJ.ID AND CU.PRT_CODE = 'TEST2'
Any tips on how to use joins and unions effectively in SQL queries when it comes to play with multiple tables?