Archives of the TeradataForum
Message Posted: Wed, 04 Aug 2004 @ 22:15:41 GMT
| Subj: | | Re: PMON explain window |
| |
| From: | | Christie, Jon |
Probably never.
The PMON explain is produced by examining the steps sent to the dispatcher (the output of the gen phase). The bteq explain is produced by
walking the white tree (the output of the optimizer phase which comes before the gen phase). The visual explain should be the same as the bteq
explain except that it has been GUIed up.
The bteq explain will always have logical spool numbers because that's what's in the white tree. The PMON explain will always have real spool
numbers because that's what's in the steps. The bteq explain has estimates because they're in the white tree. The PMON explain has no estimates
because there are none in the steps. The bteq explain has table and database names because they're in the white tree. The PMON explain only has
database and table ids (which you have to write queries to look up) because that's all that's in the steps.
Whenever I have to deal with a PMON explain, I go get a bteq explain. It doesn't take long, and the bteq explain is more useful.
Jon
| 
