Re: [Geotools-devel] ContentDataStore transactions are not really properly isolated?

2018-12-07 Thread Jody Garnett
Yeah I understand; so introducing a read write lock should address this does it not? One writer has reached commit and is trying to obtain a write lock no further readers are let out. We have to wait for then to settle down and complete before the commit can proceed. That is we need to wait on th

Re: [Geotools-devel] ContentDataStore transactions are not really properly isolated?

2018-12-07 Thread Andrea Aime
Hi Jody, I think we agree on the two transaction case, what is giving me more trouble right now is the lack of isolation between readers got out of transaction and writers committing a transaction, leaving readers (temporarily) going over a corrupted file. Cheers Andrea On Fri, Dec 7, 2018 at 8:

Re: [Geotools-devel] ContentDataStore transactions are not really properly isolated?

2018-12-07 Thread Jody Garnett
Makes sense, think we arrived at the same spot (narrowing the conflict down to the commit). The comment about responsibility for readers and writers was with respect to encapsulation (because it is response we can fix it one location). It is just hard to talk clearly about this as we have two leve

Re: [Geotools-devel] ContentDataStore transactions are not really properly isolated?

2018-12-07 Thread Andrea Aime
On Fri, Dec 7, 2018 at 6:42 PM Jody Garnett wrote: > Yeah I am aware of the gap, we did not implement a two phase commit. > > Can we introduce those read/write locks into TransacationStateDiff? I > thought the object was already responsible for producing reader and writer > wrappers which should

Re: [Geotools-devel] ContentDataStore transactions are not really properly isolated?

2018-12-07 Thread Jody Garnett
Yeah I am aware of the gap, we did not implement a two phase commit. Can we introduce those read/write locks into TransacationStateDiff? I thought the object was already responsible for producing reader and writer wrappers which should give us a clean way to do it? For clarity we “only” need to o

[Geotools-devel] ContentDataStore transactions are not really properly isolated?

2018-12-07 Thread Andrea Aime
Hi, I am looking at removing a read/write found in the image mosaic, which guards all read/write operations against GeoTools data stores, so that no to writes can occur in parallel, and no writes can occur in parallel with reads. My first reaction was "hey, datastores can already handle this, why