Maximum Size for UDT

21 Jan 2006 8:45 PM

Leila

Hi,
I want to use UserDefined format for my CLR UDT and I need a formula to
calculate its MaxSize.
Thanks in advance,
Leila

21 Jan 2006 9:34 PM

Niels Berglund

"Leila" <Lei***@hotpop.com> wrote in
news:eVTHivsHGHA.2300@TK2MSFTNGP15.phx.gbl:

> Hi,
> I want to use UserDefined format for my CLR UDT and I need a formula
> to calculate its MaxSize.

There is as such, no formula. A UDT can not be bigger than 8k, so the
sum of the sizes of all fields in the UDT is not allowed to be greater
than 8K. In other words, if you have three integer fields, the size is
12. The pronlem occurs when you have variable length fields (strings for
example), then you have to make sure the combined size of the fields do
not exceed 8k.

Niels

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**************************************************
* Niels Berglund
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* nielsb@no-spam.develop.com
* "A First Look at SQL Server 2005 for Developers"
* http://www.awprofessional.com/title/0321180593
**************************************************

21 Jan 2006 9:42 PM

Dejan Sarka

> I want to use UserDefined format for my CLR UDT and I need a formula to
> calculate its MaxSize.
> Thanks in advance,

You have to implement the Write method by yourself, so it is up to you how
long will it be. You have to persist your internal members (variables). So
you check how many of them there are to persist, which data type do they
use, etc. Also, you might add some (8?) bytes in the beginning of the
serialized data for ordering and indexing.

--
Dejan Sarka, SQL Server MVP
Mentor, www.SolidQualityLearning.com
Anything written in this message represents solely the point of view of the
sender.
This message does not imply endorsement from Solid Quality Learning, and it
does not represent the point of view of Solid Quality Learning or any other
person, company or institution mentioned in this message

21 Jan 2006 9:46 PM

Bob Beauchemin

Hi Leila,

There are only two serialization choices in the SQL Server 2005 RTM. With a
Format.Native UDT, you don't need to (in fact shouldn't) specify
MaxByteSize, the Native serialization code will figure it out. Format.Native
has some additional requirements, though, you can't use it with all UDTs.
Check BOL for these requirements.

The other choice is Format.UserDefined. With this format, you are in control
of the UDT serialization, so you must know how you're going to write the UDT
and what MaxByteSize should be.

In no case can the UDT MaxByteSize exceed 8000 bytes in this release.

Cheers,
Bob Beauchemin
http://www.SQLskills.com/blogs/bobb

Show quote

"Leila" <Lei***@hotpop.com> wrote in message
news:eVTHivsHGHA.2300@TK2MSFTNGP15.phx.gbl...
> Hi,
> I want to use UserDefined format for my CLR UDT and I need a formula to
> calculate its MaxSize.
> Thanks in advance,
> Leila
>
>
>

21 Jan 2006 11:22 PM

Leila

Thanks every body :-)
I had poblem with this sentence: "Number of control bytes of overhead
incurred from serializing a binary stream".
By reading your replies, I realized that I must not be worried about
calculating these extra bytes if I am using Format.Native!
But should I still care about it when I'm using Format.UserDefined? or there
will not be extra overhead in addition to what I write on disk?

Leila

Show quote

"Bob Beauchemin" <no_bobb_spam@sqlskills.com> wrote in message
news:ORgVKQtHGHA.2012@TK2MSFTNGP14.phx.gbl...
> Hi Leila,
>
> There are only two serialization choices in the SQL Server 2005 RTM. With
> a Format.Native UDT, you don't need to (in fact shouldn't) specify
> MaxByteSize, the Native serialization code will figure it out.
> Format.Native has some additional requirements, though, you can't use it
> with all UDTs. Check BOL for these requirements.
>
> The other choice is Format.UserDefined. With this format, you are in
> control of the UDT serialization, so you must know how you're going to
> write the UDT and what MaxByteSize should be.
>
> In no case can the UDT MaxByteSize exceed 8000 bytes in this release.
>
> Cheers,
> Bob Beauchemin
> http://www.SQLskills.com/blogs/bobb
>
>
> "Leila" <Lei***@hotpop.com> wrote in message
> news:eVTHivsHGHA.2300@TK2MSFTNGP15.phx.gbl...
>> Hi,
>> I want to use UserDefined format for my CLR UDT and I need a formula to
>> calculate its MaxSize.
>> Thanks in advance,
>> Leila
>>
>>
>>
>
>

22 Jan 2006 6:07 PM

William Stacey [MVP]

I was thinking they should add a Format.None so you could have something
like an Array type they really needs more then 8K, and you don't need as a
column type either - you just need the type to work with.

--
William Stacey [MVP]

Show quote