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Archives of the TeradataForum
Message Posted: Thu, 03 Jun 2010 @ 12:32:57 GMT
| Subj: | | Re: Multiload and fastload session count |
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| From: | | Geoffrey Rommel |
Hold on here! The original question was "what is the max session number for fastload and multiload?" The replies so far, however, have been
about the total number of load jobs running on the system. MaxLoadTasks etc. are DBS Control parameters and should NOT be changed unless you have
a good reason.
Sessions are different. Each load job uses a certain number of sessions, and that number can be different for each job. If you don't specify a
number, the load utilities will query the target system to find out how many AMPs it has and start that many sessions; for instance, if you have
48 AMPs, it will start 48 sessions. This number is usually much too large; 6-8 sessions do all the work and the others sit idle. I recommend
loading the same data repeatedly with differing numbers of sessions and timing the jobs. You will probably find that the optimal number of
sessions is about 1/10 the number of AMPs.
The *maximum* number of sessions on a system is determined by the number of Parsing Engines. Each PE can handle 120 sessions, so if you have 4
PE's you can have a total of 480 sessions. (Again, this can be changed but usually shouldn't be.) The systems are sized so that you will probably
never reach this limit, but if you do you'll get one of my favorite errors, 8024: "All virtual circuits are currently in use."
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