Re: [basex-talk] BaseX 7.9 unstable

[Alexander Holupirek]

> On 13. Sep 2017, at 11:28, Steinhauer, Dorothea 
>  wrote:
> 
>>> On 13. Sep 2017, at 10:06, Steinhauer, Dorothea 
>>>  wrote:
>>> 
>>> Hi,
>>> 
>>> we use BaseX 7.9 and we have the problem that in some (non-replicable) 
>>> situations no more data is written to the database.
>>> The database is still readable.
>>> Logfiles are currently not available.
>>> 
>>> If the problem is known, can changes to properties help?
>>> 
>>> For us, it is not an option to switch to a newer version of the baseX-DB 
>>> because API changes would be a huge effort.
>>> 
>>> 
>>> Thanks,
>>> Dorothea
>> 
>> I think, you would have to detect the pattern that leads to the unwanted 
>> behaviour.
>> Maybe the documentation on Transaction Management [1] can help to reason 
>> about the problem?
>> 
>> By the way, what do you mean with 'no more data is written to the database'. 
>>  Never ever again after some situation or during a phase (and later on it 
>> possible again)?
>> 
>> Thanks,
>>  Alex
>> 
>> [1] http://docs.basex.org/wiki/Transaction_Management#Concurrency_Control
> 
> 
> Hi,
> 
> we use the database in production, so we can't wait if anything changed. You 
> wanted to know with the question whether the database is permanently locked?

I have problems to understand what 'no more data is written to the database' 
actually means.
- Is it there a permanent write-lock on the database?
- Or is the database corrupt after a write operation?
- Or can't you write at some point in time and then, at later point, once again 
write to the database?

> When the database is "write-locking", is it possible to back up our data?

When a write operation alters the database you can not read (or write) the 
database [1], so a regular backup is not possible.

What you nevertheless can do, is, on the OS-level and only for debugging and 
failure analysis, copy the database directory to another location and, for 
instance, inspect [2] the state of the database.

Perhaps you can elaborate a bit on your whole scenario. How does your 
application operate? What do you do, if you encounter a situation in which you 
can not write to the database? Can you make a guess what is happening in your 
application when the situation occurs?

Cheers,
Alex

[1] http://docs.basex.org/wiki/Transaction_Management#Concurrency_Control
[2] http://docs.basex.org/wiki/Commands#INSPECT

Re: [basex-talk] BaseX 7.9 unstable

[Alexander Holupirek]

Hi Dorothea,

> On 13. Sep 2017, at 10:06, Steinhauer, Dorothea 
>  wrote:
> 
> Hi,
>  
> we use BaseX 7.9 and we have the problem that in some (non-replicable) 
> situations no more data is written to the database.
> The database is still readable.
> Logfiles are currently not available.
> 
> If the problem is known, can changes to properties help?
> 
> For us, it is not an option to switch to a newer version of the baseX-DB 
> because API changes would be a huge effort.
>  
>  
> Thanks,
> Dorothea

I think, you would have to detect the pattern that leads to the unwanted 
behaviour.
Maybe the documentation on Transaction Management [1] can help to reason about 
the problem?

By the way, what do you mean with 'no more data is written to the database'.  
Never ever again after some situation or during a phase (and later on it 
possible again)?

Thanks,
Alex

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