Re: [jbosscache-dev] CacheLoader preload with region based marshalling
Brian,
Looking at JBCACHE-1009, do you still see value in preloading regions
as regions are activated? If we do do this, there are a few things we
need to think about:
1. Regions being created on the fly. E.g., in <preload> I have /.
And no regions are created. DefaultInactive is true. I start the
cache, preload / (including /a/b) and then create a new region, /a/b.
Which is inactive. Would this wipe state in that region?
2. As above, but what happens to active sub-regions?
3. Overwriting. I create region /a and /a/b/c. Both are preloaded.
I now create a new region, /a/b, which is inactive on startup and I
now activate. I am assuming anything now in memory for /a/b would be
erased and overwritten with state in the CL?
And this is just the start - I see a whole can of worms here. :-)
Cheers
Manik
On 6 Jun 2008, at 10:04, Manik Surtani wrote:
On 5 Jun 2008, at 13:39, Brian Stansberry wrote:
> The regions are created/registered after start(); i.e. after the
> point shown in the logs. This is why I think it might just be a
> configuration mistake that's been in AS 5 all along; just wasn't
> exposed due to JBCACHE-1358. (In AS 4 there is no cacheloader
> involved.)
>
> Perhaps w/ region-based marshalling I shouln't use <preload>/</
> preload>. A nice fix to http://jira.jboss.com/jira/browse/JBCACHE-1009
> would include logic to defer the preload until regions are
> activated.
Yes, agreed. And this is not necessarily overly complex to do either:
When preloading stuff from cache loader:
1) Loop through all Fqns to be preloaded.
2) For each Fqn being preloaded, if any state is regionalised (i.e.,
a non-null region) check if the region is activated. If so, proceed
as normal, if not skip.
When a region is actvated:
1) Check if the region is a sub-region of any "preload" Fqns
specified in your cache loader cfg.
2) If so, attempt to preload that Fqn, but only for regions that
match the one being activated. Skip others.
I wonder if it is worth fixing JBCACHE-1009 in 2.2.0. It would
warrant another CR in 2.2.0 though. Thoughts? Votes on this?
> TBH, I don't see why I want <preload>/</preload> at all for this
> usage.
Yes - isn't lazy loading a virtue here anyway? :-)
And re: 2.1.1.GA, since JBCACHE-1358 is an obvious bug in JBC, I may
port this fix to 2.1.X which will cause future 2.1.X releases to
break in the same way.
Cheers
Manik
--
Manik Surtani
Lead, JBoss Cache
manik(a)jboss.org
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Manik Surtani
Lead, JBoss Cache
manik(a)jboss.org