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From Vincent Poon <vincentp...@apache.org>
Subject Re: "upsert select" with "limit" clause
Date Wed, 12 Dec 2018 18:42:02 GMT
For #2, can you provide the table definition and the statement used?  e.g.
Is the table immutable, or does it have indexes?

On Tue, Dec 11, 2018 at 6:08 PM Shawn/Xiang Li <shawnlijob@gmail.com> wrote:

> Hi,
>
>
>
> 1.       Want to check what is underlying running for limit clause used
> in the following Upsert statement (is it involving any coprocessor working
> behind?):
>
>
>
> *                                  upsert into table2 select * from table1
> limit 3000000; * (table 1 and table 2 have same schema)
>
>
>
>               The above statement is running a lot slower than without
> “limit”  clause as shown in following, even the above statement upsert less
> data:
>
>
>
> *                                upsert into table2 select * from table1;*
>
>
>
> 2.       We also observe memory usable is pretty high without the limit
> clause (8gb vs 2gb), sometimes for big table it can reach 20gb without
> using limit clause.  According to phoenix website description for upsert
> select “If auto commit is on, and both a) the target table matches the
> source table, and b) the select performs no aggregation, then the
> population of the target table will be done completely on the server-side
> (with constraint violations logged, but otherwise ignored).”
>
>
>
>                My question is If everything is done on server-side, how
> come we have such high memory usage on the client machine?
>
>
>
> Thanks,
>
> Shawn
>

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