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Archives of the TeradataForum
Message Posted: Wed, 05 Apr 2006 @ 15:43:03 GMT
| Subj: | | Re: TPUMP Blocking on multiple sessions |
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| From: | | Hassinger, Bill |
I was corrected by an earlier email, in that hash collisions are at the full row hash 4 bytes, not the DSW which is 2 bytes used to assign AMP.
With 4 bytes and a UPI, row hash collisions are unlikely.
I do however wonder if the blocking can still be caused by a relationship of pack size, number of AMPs, and DSW. TPUMP is still writing to a
very finite number of AMPs, so if all the rows of the pack happen to the same AMP, the rows and sessions are sequentially blocking each other. In
other words is the blocking an I/O issue, and not necessarily a hash collision issue.
Bill H
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