[mapguide-internals] Avoiding unnecessary Tile Cache invalidation (Trac Ticket 1332)

[Zac Spitzer]

a base layer group could be treated as a layer?

this is really a frustrating issue for my clients as well

z

On 28 April 2010 11:04, Jason Birch <jason at jasonbirch.com> wrote:
> WOULD increase (no way of referencing external tile sets currently)
>
> On 2010-04-27, Jason Birch <jason at jasonbirch.com> wrote:
>> My suggestion has always been to treat tile sets as separate resources
>> and allow them to be included in multiple map definitions. This
>> increases usefulness and stability all in one go.
>>
>> On 2010-04-27, Jackie Ng <jumpinjackie at gmail.com> wrote:
>>>
>>> Hi All,
>>>
>>> At Zac's suggestion, I'm spawning this thread off of discussions on Trac
>>> #1332 (http://trac.osgeo.org/mapguide/ticket/1332) to stimulate some more
>>> discussion on this list.
>>>
>>> Sometime last week, I heard a tale of total frustration about how a Tile
>>> Cache of 1.5 million tiles that was built over 1.5-2 days was instantly
>>> trashed the moment a dynamic untiled layer was added to the map
>>> definition
>>> and saved back into the repository.
>>>
>>> That got me thinking about whether something as innocuous as changing the
>>> description or background color of a map definition w/ tiled layers would
>>> invalidate the tile cache so I tested this out and just as I feared, it
>>> indeed wiped out the tile cache.
>>>
>>> My initial thoughts were that tiling's only concerned with the base layer
>>> settings in the Map Definition. So theoretically speaking, doing
>>> modifications that don't affect the base layers should not affect the
>>> integrity of the original tiles.
>>>
>>> Now according to Tom, there is a whole stack of dependencies that would
>>> have
>>> to be checked such as Feature Source changes, Symbol changes, Layer
>>> Definition changes in order to determine whether a Map Definition's Tile
>>> Cache needs to be rebuilt. I wonder what overhead would be incurred by
>>> performing these checks (if it hasn't been done already).
>>>
>>> There's also renaming the tile cache directory before saving (also
>>> suggested
>>> by Tom) and then renaming back. I wonder what other things can be done so
>>> that the Tile Cache is cleared *only* if it has to be.
>>>
>>> - Jackie
>>> --
>>> View this message in context:
>>> http://osgeo-org.1803224.n2.nabble.com/Avoiding-unnecessary-Tile-Cache-invalidation-Trac-Ticket-1332-tp4971985p4971985.html
>>> Sent from the MapGuide Internals mailing list archive at Nabble.com.
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>>>
>>
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-- 
Zac Spitzer
Solution Architect / Director
Ennoble Consultancy Australia
http://www.ennoble.com.au
http://zacster.blogspot.com
+61 405 847 168