Archives of the TeradataForum
Message Posted: Mon, 21 Jun 2004 @ 22:36:38 GMT
| Subj: || || Re: AMP Worker Tasks and Skewed Queries |
| From: || || Ballinger, Carrie |
Teradata will release a given AMP worker task at the time that particular AMP completes that query step. Each AMP will make a notification
that it has completed that query step, and then frees up its AWT for other work. Only the last AMP done with that step does the additional work
of notifying the dispatcher that all AMPs are done and the next step can be sent. So if the step is highly skewed, some AMPs will be holding AWTs
on behalf of that step, while other AMPs will have completed and released their AWT to do other work.