Quantcast
Channel: Teradata Forums - All forums
Viewing all articles
Browse latest Browse all 27759

Performance Tuning Merge Statement - response (1) by srilamaiti

$
0
0
Here is the explain plan for the same:-     1) First, we lock a distinct EDW_PR_WORK_DB."pseudo table" for read      on a RowHash to prevent global deadlock for      EDW_PR_WORK_DB.SWM_SLS_AGG_NEW.    2) Next, we lock a distinct EDW_PR_WORK_DB."pseudo table" for write      on a RowHash to prevent global deadlock for      EDW_PR_WORK_DB.F_MOBILE_APP_TD_SLS.    3) We lock EDW_PR_WORK_DB.SWM_SLS_AGG_NEW for read, and we lock      EDW_PR_WORK_DB.F_MOBILE_APP_TD_SLS for write.    4) We do an all-AMPs merge with matched updates into      EDW_PR_WORK_DB.F_MOBILE_APP_TD_SLS from      EDW_PR_WORK_DB.SWM_SLS_AGG_NEW with a condition of (      "(EDW_PR_WORK_DB.F_MOBILE_APP_TD_SLS.LOC_ID =      EDW_PR_WORK_DB.SWM_SLS_AGG_NEW.LOC_ID) AND      ((EDW_PR_WORK_DB.F_MOBILE_APP_TD_SLS.GNRC_ITEM_ID =      EDW_PR_WORK_DB.SWM_SLS_AGG_NEW.GNRC_ITEM_ID) AND      (EDW_PR_WORK_DB.F_MOBILE_APP_TD_SLS.GNRC_ITEM_LVL_CD =      EDW_PR_WORK_DB.SWM_SLS_AGG_NEW.GNRC_ITEM_LVL_CD ))").  The number      of rows merged is estimated with low confidence to be 95,074,664      rows.    5) Finally, we send out an END TRANSACTION step to all AMPs involved      in processing the request.   -> No rows are returned to the user as the result of statement 1.   

Viewing all articles
Browse latest Browse all 27759

Trending Articles



<script src="https://jsc.adskeeper.com/r/s/rssing.com.1596347.js" async> </script>