Hi David,

this is maybe something we could append to the documentation that Christian already
pointed you to.

As far as I get it, the concurrency management works single writer/multiple reader.
If you are writing to database A all reads on said database are blocked until modification
is finished. Other databases may still be readable, depending on whether the compiler
can figure out if it is safe.

--> If you call db:add() on database A, you cannot read on database A. All other dbs might
still be accessible. If you start another server process P2 you might run into problems when
process P1 starts another update operation (because this one doesn't know about P2's reads).

I hope this wraps it up correctly ...
Lukas


On Thu, Mar 5, 2015 at 1:55 PM, Christian Grün <christian.gruen@gmail.com> wrote:
Hi David,

Thanks for your mail. If i get it right, you are adding a new XML file
into a database, using the client/server architecture, and you'd like
to read documents from another database, right? This shouldn't be a
problem. What API are you working with (how do you add the new file)?

Cheers,
Christian

PS: You are invited to also have a look into our Wiki article on
transactions [1].

[1] http://docs.basex.org/wiki/Transaction_Management


On Thu, Mar 5, 2015 at 1:31 PM, David Mathei <david.mathei@gmail.com> wrote:
> Hello BaseX Team,
>
> I am loading a big file into BaseX (2.1G) and try to understand the handling
> of concurrent reads during that process. The size does only matter in so
> far, as loading seems to block reading for an extended amount of time.
>
> I observe that I can not read the collection I'm loading into nor any other
> collection under the same server. When I use another server process on a
> different port to write to the target collection I can read other
> collections without delay, the collection I'm loading into is (obviously)
> blocked by the upd.basex flag.
>
> Is there no parallelisation involved that would separate reading from
> writing processes, or does that only come into play for xquery updates that
> run under the transaction module?
>
> My PARALLEL setting is at the default of 8 and I'm on version 8.0.1. And I
> apologise already if I missed some obvious configuration...
>
> Thanks to everyone involved in this project!
>
>
>
> David Mathei
>