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Archives of the TeradataForum
Message Posted: Thu, 01 Dec 2005 @ 10:30:15 GMT
| Subj: | | Re: Is collect statistics ok along with read lock |
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| From: | | Victor Sokovin |
| | Yes, we can run COLLECT STATISTICS on a table that already has a READ lock. The COLLECT STATISTICS just reads the table so it will not have
any lock conflict with another READ lock. This is not a V2R6.1 feature. | |
Thanks for the confirmation. I think this justifies the hope expressed in the original question in this thread, and this is indeed not new in
TD.
I have tried to place the question in a broader context, though: possibilities for concurrent, on-line activities such as, say, normal queries,
loads and statistics collection. Statistics collection on earlier releases has traditionally been done "overnight", in the reserved window when no
loads or user queries were permitted.
On-line statistics collection concept as I understood it at the NCR presentation on extreme availability features would imply, for example,
that execution plans of queries which intersect in time with the statistics collection process would not be adversely affected (for as much as it
is at all possible).
In the R6.1 release summary, I can find information on another extreme availability feature mentioned in the presentation: on-line rebuild of
join indexes. I only mention this one to describe the context in which I heard about the on-line statistics collection. As I said earlier, the
feature might only be possible to implement on the dual active configuration, not on a single database system (dual active was the motto of the
day). That's what I would like to clarify, if possible.
Regards,
Victor
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