| As part of my Job i was optimizing a Data warehouse query which builds the update for the Fact table . The query Contains numerous update statements. Run The query and it took 365 Seconds to complete . |  |
I saw the Execution plan , there is no missing index and most of the thinks looks normal at the First glance.Hence i had too many update statements i was puzzled, there is no missing index showing from the execution plan. A Big question mark. Didn’t gave up and continued about which update is causing me the trouble, best thing i did was. I Started executing one by one. From among the updates , one of the update statement took more than 340 seconds . So i got the area where i need to do my analysis .
Breaking a query into smaller parts and examine one by one helped me in lot of cases . So a part which gave a challenge is a single update statement, updating the a value to a column based on the numerous case statements.
 | This image throws me big hint. Resembling update on your clustered index. I saw the execution plan and noticed 75% cost on updating the clustered index , also this update statement affects 15 Lacks records . |
No comments:
Post a Comment