Hi Swaminathan,

as i see, you are not using the server. Multiple request handling is only supported by the server-client architecture.

You should try it like in this example: http://www.inf.uni-konstanz.de/dbis/basex/code.php?code=ServerConcurrencyExa...

Kind regards, Andreas

Swaminathan S schrieb:

Hi Andreas,

Please find attached a test program (Please substitute the xml file and xquery- I had used my application data which is about 1.5MB xml file and it is confidential).

I got a BaseX error (attached) while doing both reads and writes parallely. But, It worked fine when I did reads only parallely or writes only parallely.

Thanks and regards,

Swaminathan S

On Mon, Mar 8, 2010 at 4:35 PM, Andreas Weiler <andreas.weiler@uni-konstanz.de mailto:andreas.weiler@uni-konstanz.de> wrote:

Hi Swaminathan,

BaseX is handling requests as multiple reader and single writers.
All update queries will be queued and then processed one by one
(doesnt mather on same or different xml).
Read queries will be processed simultaneous.

    I need to design the concurrency aspect.

We would be pleased about your results.

Kind regards,
Andreas (BaseX Team)

Swaminathan S schrieb:

    Hi,

    Suppose BaseX receives several requests(updates/queries) (on
    same or different xml) almost simultaneously, how will BaseX
    handle this? I mean does BaseX queue all requests and process
    one by one or the application querying BaseX needs to ensure
    that a second request does not reach BaseX till the first
    request is completed by BaseX?

    Since I am working on an application that handles operations
    for multiple xmls parallely, I need to design the concurrency
    aspect.

    Thanks and regards,

    Swaminathan S
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Hi Swaminathan,

in XQuery Update you can define and use a large number of xml's in an update, so it's pretty hard to define a good concurrency control which keeps up the good speed of BaseX and secures the queries too. So we decided to implement it as single writer. Maybe it will be enhanced to multiple writers in future releases. If you create your own concurrency controls, there shouldnt be any problems with updating different XMLs.

Kind regards, Andreas

Swaminathan S schrieb:

Hi Andreas,

You said: "All update queries will be queued and then processed one by one (doesnt mather on same or different xml)." Ideally, update queries on different xmls should be designed to run parallely? One of the reason I ask this is: Suppose I do not use server-client architecture(I use BaseX classes directly) and I introduce concurrency controls myself, should I expect any problems if I do concurrent writes on different XML?

Thanks,

Swaminathan Sahiram

On Mon, Mar 8, 2010 at 4:35 PM, Andreas Weiler <andreas.weiler@uni-konstanz.de mailto:andreas.weiler@uni-konstanz.de> wrote:

Hi Swaminathan,

BaseX is handling requests as multiple reader and single writers.
All update queries will be queued and then processed one by one
(doesnt mather on same or different xml).
Read queries will be processed simultaneous.

    I need to design the concurrency aspect.

We would be pleased about your results.

Kind regards,
Andreas (BaseX Team)