Re: [basex-talk] A few general questions about BaseX

Hi Anastasiou,

:-)

Am 12.09.2017 um 10:54 schrieb Anastasiou A. a.anastasiou@swansea.ac.uk:

Hello everyone

I am trying to load BaseX with a large number of XML files (~500), each one a few hundreds of MBs big. BaseX fails with a message along the lines “This is too big for one database”.

=> might be that you hit one of our database limits. See the first line here for general limits: http://docs.basex.org/wiki/Statistics http://docs.basex.org/wiki/Statistics

Can I please ask:

1.  Are there any logs, beyond the DB logs? If yes, where can I find them?
   

a. The reason I am asking is because once basexgui gives the message, there is no indication about the error. Ideally, I would like to know if this is a limitation on memory amount or number of items (?).

The database logs are all there is. You can use the admin module to add your own messages to these logs, http://docs.basex.org/wiki/Admin_Module#admin:write-log http://docs.basex.org/wiki/Admin_Module#admin:write-log

So for example in a try / catch block you could log more explicitly whats happening :)

2.  The parser options include reading XML files from archives, which is very convenient, but once the file has been 
   

parsed, does BaseX require the “originals” for queries / returning results?

If you created a database from your archive, i.e. db:create(‚foo.zip‘,…) the original files are no longer needed. http://docs.basex.org/wiki/Database_Module#db:create http://docs.basex.org/wiki/Database_Module#db:create

3.  Is it possible to do federation with BaseX? In other words, let’s say I split a database in two large parts (as per #1), 
   

is it possible to launch two baseX servers and then have them talk to each other so that ultimately I just query one of them and get back unified results?

Yes, it is possible, but only if you are willing to suffer a little :-) You can use the http://docs.basex.org/wiki/Client_Module http://docs.basex.org/wiki/Client_Module to connect to a running basex server and you could use the http://docs.basex.org/wiki/XQuery_Module#xquery:fork-join http://docs.basex.org/wiki/XQuery_Module#xquery:fork-join to connect to multiple servers at once, pose a query and return the results.

But expect to do some stuff by hand: i.e.:

- maintain a list of servers you currently have - handle storing, deleting and updating documents - handle document retrieval, …

So a probably large bit of manual work is absolutely required, but depending on what you need to do with your documents it might work "well enough“ :-)

If you need more information let me know!

Best Michael

All the best