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[ChristianGruen]

Hi Andy, I finally had some time to look at your project (actually, I did do so two weeks ago). I haven’t completely thought it through, but I also believe that the only chance to have real asynchronous queries is to create a completely new query process, and (as long as there is no way to serialize XQuery expressions) to pass the query on as string.

I could possibly add a new xquery:fork($func as xs:string) as empty-sequence() function in BaseX, which does exactly that (the query could be both updating or non-updating). As you are actually doing more than this, I’ll spend some more time on this before implementing anything by myself… Thanks!

[ChristianGruen]

Btw: As we can always use try/catch in a query, I am not sure if we really need then/fail branches. Of course it may happen that a query cannot be evaluated at all, but this usually happens if a query contains parsing errors, which can be fixed in advance.

[james-jw]

I think the xquery:fork-eval function you propose would be great.

I often find executing refined xquery expressions within the context of a larger expression garners way better performance. For example see xq-hunt.

Being able to fork that evaluation, including updates would be great.

In regards to try/catch... then/fail is not the same as its more dynamic in nature, allowing for conditional try/catch logic which in the context of certain applications, such as meta programming is highly desirable.

[apb2006]

Thanks for the comments.

I would see something like xquery:fork($func as xs:string,$opts as map(*)) as xs:string
where the return would be some sort of handle to the task, for cancelling etc.

[ChristianGruen]

I would see something like xquery:fork($func as xs:string,$opts as map(*)) as xs:string
where the return would be some sort of handle to the task, for cancelling etc.

Sounds reasonable. Ideally, such a thread id could then also be utilized to fetch a cached result. We’d additionally need to decide how long results will be cached before they are invalidated, etc.

I’ve added some more thoughts in BaseXdb/basex#1211.