MVStore -- can I ignore it?
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SkiAddict
Dec 21, 2016, 12:23:11 AM12/21/16
to H2 Database
So after managing to resolve my slow console launch problem, I'm back to actually working with h2. First question: what version to use? I was on 1.3.167 but would like to use something more up to date. 1.3.176 still gives me an error on opening the database (something about not being able to find the class -- in my Java frontend application -- which implements a database function) but 1.4.193 doesn't. However, 1.4.193 has this MVStore thingie, which I'm not too sure about.
I've had a quick read of this, but it seems to be written for an audience who will use the MVStore features in their code directly. I simply use h2 as a standard SQL database, from my Java frontend.
So: are there reasons I should avoid 1.4.193? Is there anything special I need to do to use it? (e.g. file conversion, like we had to do when upgrading from 1.1) Can I ignore MVStore altogether? I see that I can now get the h2 console to open a database which is already opened by my Java frontend -- but only if I don't add MV_STORE=FALSE to my console's URL. What are the tradeoffs here? What are the secondary effects of not adding that to the URL? And finally: have I already harmed my database file by opening it both with and without MV_STORE=FALSE?
Many thanks :-)
I've had a quick read of this, but it seems to be written for an audience who will use the MVStore features in their code directly. I simply use h2 as a standard SQL database, from my Java frontend.
So: are there reasons I should avoid 1.4.193? Is there anything special I need to do to use it? (e.g. file conversion, like we had to do when upgrading from 1.1) Can I ignore MVStore altogether? I see that I can now get the h2 console to open a database which is already opened by my Java frontend -- but only if I don't add MV_STORE=FALSE to my console's URL. What are the tradeoffs here? What are the secondary effects of not adding that to the URL? And finally: have I already harmed my database file by opening it both with and without MV_STORE=FALSE?
Many thanks :-)
Noel Grandin
Dec 21, 2016, 2:15:40 AM12/21/16
to h2-da...@googlegroups.com
MV_STORE is a completely separate storage engine from the old PageStore.
The old PageStore engine generates files with a .h2.db extension, the new MV_STORE engine generates files with a .mv.db extension.
So it's not possible to mix and match opening the same files with the different engines.
I and some other people currently use MV_STORE in production, but there may still be some issues. If you have .h2.db database files from the 1.3 series that you want to carry on using, then you will need to use the old PageStore engine.
SkiAddict
Dec 21, 2016, 3:26:49 AM12/21/16
to H2 Database
Thanks Noel for such a clear explanation of the situation :-)
As I understand it, eventually all h2 databases will be MV_STORE ones? In which case I'm going to need to migrate my .h2.db file sooner or later? IOW I may as well do it now, esp since 1.3.176 gives me an error and I'd rather move beyond 1.3.167.
How do we migrate to the MV_STORE format?
As I understand it, eventually all h2 databases will be MV_STORE ones? In which case I'm going to need to migrate my .h2.db file sooner or later? IOW I may as well do it now, esp since 1.3.176 gives me an error and I'd rather move beyond 1.3.167.
How do we migrate to the MV_STORE format?
Noel Grandin
Dec 21, 2016, 3:35:58 AM12/21/16
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On 2016/12/21 10:26 AM, SkiAddict wrote:
>
> How do we migrate to the MV_STORE format?
>
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