multi-process concurrency

[Jonathan Rudenberg]

What are the multi-process concurrency semantics of Sophia? Can I open the database for read access concurrently from another process? What is the procedure to take a consistent, reliable backup?

Thanks,

Jonathan

[Dmitry Simonenko]

Right now there is no support for direct multi-thread or multi-process access. There should be no issues using separate repositories in separate threads, or use single database instance and do sp_set/get access with your own lock.

There should be no issues to implement this for the main Sophia api, since it's mostly implemented for internal uses. I'm planing to add this feature when i get a free time, hopefully on the weekend :)

Right now the only procedure to make a backup is to close the database handle and copy the database repository. Hot-backups are also planned :)

Thanks! :)

[Andrea Peruffo]

Please can we have the actual clear project situation about concurrent "things" on db (mean processes, therads, fs accesses and so...)

Thanks in advance!

[Dmitry Simonenko]

Yes, sure:

multi-thread sophia does support multi-thread access (and sophia's compaction is multi-threaded too).

multi-process sophia does not support access a same repository from different working processes at the moment.

database sophia does support creation of a additional databases (which can have their own directory) run under a 

single environment. Any number of databases can be involved in a multi-statement transactions.

append-only sophia does not do random disk access for updates.

Please let me know, if you still have any questions left.

Thanks!

[Amirouche Boubekki]

Hello,

Thanks a lot for the hard work!

On Saturday, March 21, 2015 at 10:40:56 AM UTC+1, Dmitry Simonenko wrote:

multi-process sophia does not support access a same repository from different working processes at the moment.

Is this still true?