Re: opening multiple databases from same program

 Hi

Yeah, but SwingWorker adds a lot of noise to your codebase, and it should only really be necessary for long-running things.
And my embedded database (H2) is pretty fast, so it shouldn't be necessary.

Doing detachFromThread() is working for me, so I'm going with that.

-- Noel Grandin

[email protected] wrote:
>  
>
> No SwingWorker? These have their own thread.
>
> Envoyé par mon BlackBerry Wireless Handheld.
>
> ------------------------------------------------------------------------------------------------------------------------
> *From: * Noel Grandin <[email protected]>
> *Sender: * [email protected]
> *Date: *Mon, 12 Jul 2010 14:44:22 +0200
> *To: *John Abraham<[email protected]>
> *ReplyTo: * [email protected]
> *Cc: *<[email protected]>
> *Subject: *Re: [SimpleORM] opening multiple databases from same program
>
>  
>
> Hi
>
> In Swing, a lot of operations are required to happen on the event thread, which means I end up often talking to the DB
> on the event thread, which in turn means that the two UIs both try and talk to the DB from the event thread.
>
> Sigh. Looks like I'm going to have to call
>     SSessionJdbc.open()
>     .. do some stuff....
>     SSessionJdbc.commitAndDetachDataSet();
>     SSessionJdbc.detachFromThread();
> everywhere I touch the DB.
>
> (Note: I'm not closing it because I'm reusing connections - it is very expensive to open and close an embedded database!)
>
> -- Noel
>
>
> John Abraham wrote:
>
>> I agree that multiple sessions per thread would sometimes be useful, and would support any enhancements in that
>> direction.  But in your particular case, Noel, can you not just use two threads, one per UI?
>>
>> --
>> John Abraham
>>
>>   
>> On 2010-07-12, at 7:54 AM, Noel Grandin wrote:
>>
>>>  
>>>
>>> Hi
>>>
>>> I have 2 embedded databases, and normally one UI runs on each database. But in a particular situation, the two UIs
>>> will be running the in same VM at the same time, and thus need access to both databases.
>>>
>>> I understand what the check is trying to achieve, but it would be better if it checked that there was only one
>>> session per database per thread.
>>> This should be possible by calling
>>>    javax.sql.Connection#getMetaData()->getURL()
>>>
>>> Alternatively, could we get a mechanism for disabling the check?
>>>
>>> Thanks, Noel Grandin
>>>
>>> Franck Routier wrote:
>>>
>>>>  
>>>>
>>>> Hi,
>>>>
>>>> well, AFAIK, you can't do that... !
>>>>
>>>> SSessionJdbc has built-in checks that a connection is single threaded
>>>> using a ThreadLocal object. [I think Hibernate has some kind of best
>>>> practice to achieve the same goal (I'm not formal here, I didn't use
>>>> hibernate for years)]
>>>>
>>>> There is only one dataSource per SSessionJdbc and one SSessionJdbc per
>>>> thread.
>>>>
>>>> You could implement a different strategy to handle this part. Some work
>>>> was done along this path in a previous version of Simpleorm, for using a
>>>> single JTA transaction per session. But it is not maintained.
>>>> See simpleorm/extras/SConnectionEJB.java
>>>>
>>>> My question would be : what are you trying to achieve ?
>>>>
>>>> Franck
>>>>
>>>> Le vendredi 09 juillet 2010 à 17:11 +0200, Noel Grandin a écrit :
>>>> >
>>>> > Hi
>>>> >
>>>> > I'm opening multiple different databases from the same thread, which
>>>> > is triggering this check:
>>>> >
>>>> > simpleorm.utils.SException$Error: Thread's SSession already open [SS
>>>> > 1.SkyMon]
>>>> > [0@17:08:40.976] !SE>: at
>>>> > simpleorm.sessionjdbc.SSessionJdbc.innerOpen(SSessionJdbc.java:129)
>>>> > [0@17:08:40.976] !SE>: at
>>>> > simpleorm.sessionjdbc.SSessionJdbc.open(SSessionJdbc.java:88)
>>>> > [0@17:08:40.976] !SE>: at
>>>> > simpleorm.sessionjdbc.SSessionJdbc.open(SSessionJdbc.java:108)
>>>> >
>>>> >
>>>> > What do I do?
>>>> >
>>>> > Thanks, Noel Grandin
>>>> >
>>>> >
>>>> >
>>>> >
>>>> >
>>>> >
>>>> >
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>>>
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