Re: How many fields in a table are too many

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Тема Re: How many fields in a table are too many
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Msg-id 64479.216.238.112.88.1056657800.squirrel@$HOSTNAME
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Ответ на Re: How many fields in a table are too many  (Steve Crawford <scrawford@pinpointresearch.com>)
Ответы Re: How many fields in a table are too many  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: How many fields in a table are too many  (Steve Crawford <scrawford@pinpointresearch.com>)
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> On Thursday 26 June 2003 12:44 am, btober@seaworthysys.com wrote:
>> > On Thu, Jun 26, 2003 at 03:17:12AM -0400, btober@seaworthysys.com
>> >
>> > wrote:
>> >> > I have a table with 13 fields. Is that
>> >> > too many fields for one table.
>> >> > Mark
>> >>
>> >> Thirteen? No way. I've got you beat with 21:
>> >
>> > Pfft! Is *that* all?  I've got a table with 116 fields.
>>
>
> As long as we are playing "who's is biggest", I have one with 900+
> attributes (normalized) but there is a big warning - if you have a
> query that returns hundreds of columns it will be very, very slow.
> Slow as in tens of seconds to do a "select * from fattable" when
> fattable has <1000 records.
>

Is the SELECT * the only circumstance? That is, if you specify a small
number of columns, does the response improve even though the table
actually has that large number of columns but is only be asked to supply
a column-limited result set? What about when you limit the rows but not
the columns with a WHERE clause? And of course the last case when you
limit both rows and columns?

~Berend Tober




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