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

[Jason Birch]

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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>