ADAM: Multi-valued (string) attributes: maximum number of values?

[Michael Herman (Parallelspace)]

Is there a maximum limit on the number of values a multi-valued attribute
can have?

...if so, is it based on the number of values? ...combined total storage of
the values?

My requirement is to store as many as a million values in a single attribute
(vs. having to create entity container).

Michael.

--
Michael Herman
Parallelspace Corporation
Developers of Advanced Business Collaboration Solutions for Microsoft
SharePoint, Microsoft Live Communications Server, Active Directory and
Groove Workspace
Portal and Content Migration Specialists:
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SharePoint Migration Knowledge Center:
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[Joe Kaplan (MVP - ADSI)]

My understanding is that there is no real limit for link value attributes
(DN syntax), but the limit for other types (strings and such) is around 850
for AD 2K3 and ADAM. Dmitri can probably confirm the exact numbers. I
think it is based on the number of values, not on the size.

Joe K.

"Michael Herman (Parallelspace)"
<mwherman@parallelspace.$nospam$.net.$please$> wrote in message
news:%23gj5Zqc...@TK2MSFTNGP11.phx.gbl...

[Dmitri Gavrilov [MSFT]]

That's correct. In ADAM and AD (w2k3 forest mode) the limit is around 1300
values, total per object, non-linked only, regardless of value size. In AD
(pre-w2k3 forest mode) the limit is approximately 850 values.

Now, the way people get around this is by creating a linked DN-string (or
DN-binary) attribute. This is the syntax that allows to append a string (a
blob) to a DN value. Then you can have unlimited number of values, you just
have to set the DN part to something.

The downside of this approach is that you can not index such attribute. You
can set the index bit, but it will have no effect. Linked attributes are
always implicitly indexed, and this index only includes the DN part.

We keep talking about removing the max value count limitation (which comes
from esent), but I don't think this is coming any time soon...

--
Dmitri Gavrilov
SDE, Active Directory Core

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"Joe Kaplan (MVP - ADSI)" <joseph....@removethis.accenture.com> wrote
in message news:OH5VI9d0...@tk2msftngp13.phx.gbl...

[Michael Herman (Parallelspace)]

Thanks Dmitri,

Re: creating a linked DN-string (or DN-binary) attribute

I found the MSDN reference for DN-String (2.5.5.14) here:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ad/ad/choosing_a_syntax.asp

...and they're also mentioned here in the context of Linked Attributes:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ad/ad/linked_attributes.asp

...and a DN-String attribute declaration sample can be found here:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ad/ad/ldif_scripts.asp

QUESTION: So I understand attributes when they're simple things like strings
and integers. In the case of DN-String, is it correct to think of the value
of a DN-String attribute being a 2-tuple (or loosely, a name-value pair)
consisting of a DN and a String?

Re: you can have unlimited number of values, you just have to set the DN
part to something

CONFIRMATION: So the idea is to use the String part as a string blob and not
really use the DN part?

QUESTION: What are some examples of where DN-Strings are typically used?

QUESTION: What are some examples of where Linked DN-Strings are typically
used?

Thanks,
Michael.

"Dmitri Gavrilov [MSFT]" <dmi...@online.microsoft.com> wrote in message
news:uVt$Mje0EH...@TK2MSFTNGP14.phx.gbl...

[Dmitri Gavrilov [MSFT]]

See inline.

--
Dmitri Gavrilov
SDE, Active Directory Core

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"Michael Herman (Parallelspace)"
<mwherman@parallelspace.$nospam$.net.$please$> wrote in message
news:OAQKxfp0...@TK2MSFTNGP15.phx.gbl...

> Thanks Dmitri,
>
> Re: creating a linked DN-string (or DN-binary) attribute
>
> I found the MSDN reference for DN-String (2.5.5.14) here:
>
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ad/ad/choosing_a_syntax.asp
>
> ...and they're also mentioned here in the context of Linked Attributes:
>
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ad/ad/linked_attributes.asp
>
> ...and a DN-String attribute declaration sample can be found here:
>
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/ad/ad/ldif_scripts.asp
>
> QUESTION: So I understand attributes when they're simple things like
strings
> and integers. In the case of DN-String, is it correct to think of the
value
> of a DN-String attribute being a 2-tuple (or loosely, a name-value pair)
> consisting of a DN and a String?

Yes.
http://msdn.microsoft.com/library/en-us/adschema/adschema/s_object_dn_string.asp

>
>
> Re: you can have unlimited number of values, you just have to set the DN
> part to something
>
> CONFIRMATION: So the idea is to use the String part as a string blob and
not
> really use the DN part?

Well yes. You *can* use the DN part too, if you want to.

>
>
> QUESTION: What are some examples of where DN-Strings are typically used?
>

Normally, you'd use them when you need a DN value with an additional string
qualifier. There are no dn-string attributes in the default AD schema, but
there are a few DN-binary ones. See, for example,
http://msdn.microsoft.com/library/en-us/adschema/adschema/a_wellknownobjects.asp

>
> QUESTION: What are some examples of where Linked DN-Strings are typically
> used?

Again, whenever you need a linked attribute with an attached string value.

You can also use this syntax when you need to have more than 850/1300 values
per object. AD does not use this by itself, but some of our customers do
this. Cert services, for example.

One other warning -- don't use empty DN as your dn value. We recently fixed
a bug (fix to come in SP1), which involved disallowing creating such values.
Always put some DN in -- even if you don't need it. Point to something --
self or perhaps domain head. Note you are not wasting any space doing this.
Any DN value (even empty one) is represented by a DWORD in the database.

[Joe Kaplan (MVP - ADSI)]

Another thing to watch out for is that DNBinary and DNString are somewhat
painful to deal with using the managed code APIs (System.DirectoryServices).
This is because you need to use the ADSI wrapper types to manipulate them
via COM interop. There isn't a lot of information on this as these types
are very rarely used, but most of the relevant documentation will be in the
ADSI SDK, not in S.DS.

This isn't to say that you can't make this work, though. Just that it is a
little extra work.

Joe K.

"Dmitri Gavrilov [MSFT]" <dmi...@online.microsoft.com> wrote in message

news:u7LJ5as0...@tk2msftngp13.phx.gbl...

[Michael Herman (Parallelspace)]

Thank you Dimtri and Joe for the detailed feedback,

Michael.

"Joe Kaplan (MVP - ADSI)" <joseph....@removethis.accenture.com> wrote

in message news:eywLiyw...@TK2MSFTNGP11.phx.gbl...