:)
True. I definitely won't say that this will solve all cases 100%. But
for basic rendering.. this allows you to essentially set "expires" for
fragments of the page. And yes it caches all operations that go through
PageRenderSupport. And if I could take over the markupWriter properly,
I would have cached and replayed those already.. but i couldn't easily
do that.. But on second thought, you're right, maybe I should have
cached a DOM tree.. since it would have a much better guarantees for
replaying.
But on most cases, this component works pretty darn good, and we love it.
Of course trying to do evict cache on particular events is hard.. but if
you are alright with "updates within 30hr" sort of cases. this is a good
start.
Howard Lewis Ship wrote:
I'm generally against these approached.
Cache the data, make it fast to access.
Let Tapestry do a full render every time.
You'll end up with confusing, unforseen consequences.
Rendering is increasingly a complex dance between components. That's
the power and the penalty of Tapestry. Components inside that cached
zone are not just rendering a character stream, they are generating
JavaScript, assigning unique ids (via PageRenderSupport) interacting
with an enclosing Form components, and doing other user-specific
things.
I would always look elsewhere first for places that need optimization,
and I'd start with database access and queries.
On Tue, Mar 18, 2008 at 11:22 AM, Fernando Padilla <[EMAIL PROTECTED]> wrote:
We have a component that we call "Buffer" :) it takes a timeout,
optional cachekey, and optional lastmodified (to tell you)
We have it for Tap4 and Tap5, if anyone really wants it, I bet I can
liberate it.. you would just have to change the cache hooks to use
whatever cache you want to use...
The easiest way to add caching to the app. :)
Martin Kersten wrote:
> @Chached is only used during a single page rendering cycle. It would not
> apply to your situation. (as far as I know)
>
> Source:
> http://sqllyw.wordpress.com/2008/03/15/new-features-in-tapestry-5011/
>
> Your scenario would be implementable using your own component.
> The component would represent a fragment and read the file (even
> use a inmemory cache strategy (soft/weakreferences)) and write
> the ouput directly to stream (or actually the dom tree of your
> document being returned).
>
> Using your own solution enables you to mimic the behavior you talk about.
> Another idea would to write / cache only datas needed to render the tables
> (e.g. cache only content not markup). Never the less I am in doupt,
> if such a solution is necessary (dynamically cache results of
> database queries in memory or on disk).
>
> So after all you might want to port your application. As always use
> the simpliest solution first. So database queries without any caches.
> Once you see any problems (performance is below required) just go for
> optimization. Since you have a fallback solution at hand (cron-jobs +
> disk fragments) you are at the safe side. But I am in doupt if you
> really need the markup being cached. Caching the database results
> and recreate markup sounds more reasonable. You might save you lots
> of seeking time.
>
> But you always know: Only the code / application will tell you!
>
>
> Cheers,
>
> Martin (Kersten)
>
> -----Ursprüngliche Nachricht-----
> Von: Tobias Marx [mailto:[EMAIL PROTECTED]
> Gesendet: Dienstag, 18. März 2008 17:45
> An: Tapestry users
> Betreff: @Cached and caching in general
>
> I have not used T5 yet, but would @Cached use the file system for caching
HTML fragments similiar to caching mechanisms in some php frameworks?
>
> Or is this a pure memory-based cache?
>
> I am thinking about migrating an old PHP application to T5 - it has really a
lot of traffic and any users are logged in at the same time.
>
> It is quite a low-level application that is still quite fast due to cron
jobs in the background that generate HTML fragments that are included to reduce
the database-query bottleneck (e.g. grouping/ordering and sorting of huge tables).
>
> Somehow I don't trust Hibernate for high-performance database queries on
huge tables .... as I think if tables are huge and many people access it, it will
always lead to problems...no matter how good the queries are and how well you have
splitted the data across several tables.
>
> So I think the best solution is always to generate HTML fragments in the background
that take a long time and simple "include" them....this is even quicker then
parsing templates when the data is cached. So you save the time necessary for querying the
database plus the time necessary for processing the templates that are involved.
>
> Currently the setup on this application uses one-way database replication
and the cron jobs access the the huge data table on the replicated database and
generate those HTML fragments without disturbing the web-applications performance.
So the main application simply includes those HTML fragments within milliseconds.
>
> But maybe the T5 caching mechanism would make all of those low-level tricks
redundant?
>
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