maria-discuss team mailing list archive

[Roberto Spadim <roberto@xxxxxxxxxxxxx>]

right sergei!

rowsAn *estimate *of how many rows we will find in the table for each key
lookup.


2014-05-26 21:05 GMT-03:00 Roberto Spadim <roberto@xxxxxxxxxxxxx>:

> nice :) no problems in this case
> i wasn't considering this
> i will check if documentations have this, serious i don't remember if
> something simple like this is explained and i never checked before :)
>
> if i don't found this information, i will reply here
>
>
> 2014-05-26 19:52 GMT-03:00 Sergei Golubchik <serg@xxxxxxxxxxx>:
>
> Hi, Roberto!
>>
>> On May 26, Roberto Spadim wrote:
>> > maybe include at extra "estimative rows count"
>> > just to understand what happened
>>
>> Row count in the EXPLAIN output is *always* an estimation, there is no
>> need to specify it explicitly because it is always the case.
>>
>> > > I suppose you've seen the answer in the bug report. But just for the
>> > > sake of completeness I repeat it here.
>> > >
>> > > CONNECT does not read rows several times. But in the CSV file format,
>> > > rows can have different lengths and CONNECT cannot directly know how
>> > > many rows your table has. So, it *estimates* the number of rows by
>> > > dividing the file length by the minimal row length (which it can
>> > > calculate from the table definition).
>>
>> Regards,
>> Sergei
>>
>
>
>
> --
> Roberto Spadim
> SPAEmpresarial
> Eng. Automação e Controle
>



-- 
Roberto Spadim
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Eng. Automação e Controle