XSD Length Restriction Options - xsd

Question

This is valid, but duplicates the constraints on the length using both the pattern and the maxLength to enforce it:
<xsd:simpleType name="MyType">
<xsd:restriction base="xsd:string">
<xsd:pattern value="[0-9]{0,10}" />
<xsd:maxLength value="10" />
</xsd:restriction>
</xsd:simpleType>
The pattern alone would suffice:
<xsd:restriction base="xsd:string">
<xsd:pattern value="[0-9]{0,10}" />
</xsd:restriction>
Or the pattern could be simplified and we would rely on maxLength:
<xsd:restriction base="xsd:string">
<xsd:pattern value="[0-9]*" />
<xsd:maxLength value="10" />
</xsd:restriction>
Questions:
Are there known performance implications of choosing one over the other?
Will any given parser check the len first and short circuit the validation before compiling the pattern if both are provied?
Or will both be check in any case?
Does it vary from parser to parser?
I acknowledge that the performance difference here is probably minimal. I also expect that the regex engine may also be able to short circuit of the is a length constraint--but that's a level deeper than I probably care about.
Performance aside, I think i prefer having it all in the pattern, but that may relect my comfort level with regex rather than a typical best practice.
Thanks!

Answer 1

Is your code meant to be a number or numeric string? By that I mean are leading zeros allowed? If they aren't you could make your datatype even simpler by making it a restriction of xsd:integer with a maximum length or a maximum value such as either:
<xsd:restriction base="xsd:integer">
<xsd:maxLength value="10" />
</xsd:restriction>
or
<xsd:restriction base="xsd:integer">
<xsd:maxExclusive value="10000000000"/>
</xsd:restriction>
That going to be the simplest way of describing it, as well as probably faster as you are now doing an integer check, instead of a regex check.

Answer 2

In a way, your question has a funny side too... Since even you did a mistake in translating the last pattern (+ means one ore more, you wanted * instead), it proves a point that some will say about regular expressions, an that is regex could prove tricky. Regex is a struggle for many, whether we like it or not.
I am a firm believer in "Make things as simple as possible, but not simpler".
If you can without regex, stay away from it (see above). Reference as much as you can on built in types, and the provided facets (I would think the only valid case for you is if you wanted to allow for leading zeroes, otherwise an unsignedint with constraining facets would do the same).
If you can't, but regex could do it, don't hesitate to use it.
Never duplicate your "requirements" - maintenance is the most important reason. Undeniably there's a chance for extra CPU cycles, but unless someone is overdoing it intentionally, as you said it, the overhead is most likely minimal.
I think that if you stick with these principles, your questions kind of go away...