Changes between Version 11 and Version 12 of MapGuideRfc90

Timestamp:

Oct 14, 2011, 3:29:49 AM (13 years ago)

Author:

uvlite

Comment:

align with revision 6174

MapGuideRfc90

@@ -9 +9 @@
 ||RFC Template Version||(1.0)||
 ||Submission Date||(Date/Time submitted)||
-||Last Modified|| Uv Nov 4 2010||
+||Last Modified|| Uv Oct 14 2011||
 ||Author||Zac Spitzer, Uv ||
-||RFC Status||(draft)||
+||RFC Status||(ready for review)||
 ||Implementation Status||(testing sandbox)||
-||Proposed Milestone||(2.2)||
+||Proposed Milestone||(2.3)||
 ||Assigned PSC guide(s)||(when determined)||
 ||'''Voting History'''||(vote date)||
@@ -39 +39 @@
 e.g.
 {{{
-Client -> GetTile(0,1) -> RenderMetaTile(0,0 - 1,1) -> SplitUp -> ReturnTile (0,1)
+Client -> GetTile(0,1) -> GetMetaTile(0,0 - 1,1) -> RenderFromMetaTile-> ReturnTile (0,1)
        -> GetTile(1,1) -> wait................................... ReturnTile (1,1)
 }}}
+
 == Issues ==
 
 Locking the threads to the implicit producer consumer scheme is complex and
-the file locking seems not very efficient. To improve polling delay the Polling
-configuration value has been changed to ms semantics so we can specify 500ms.
+the file locking seems not very efficient.
 
-In addition an ace_condition has been implemented to get rid of the lockfiles 
-all together and further improve the response time. (LockMethod == 3)
-In addition to the standard approach with one lock per sub tile (LockMethod == 2)
-we also experimented using a single file per metatile (LockMethod == 1).
-This is a variable in the TileService section of the serverconfig.ini together with the
-UseMetaTiles variable specifying the multiplication factor. 
+The default locking method is 0 which uses a single file per metatile (LockMethod == 0).
+LockMethod is a config value in the TileService section of the serverconfig.ini together with the
+UseMetaTiles value specifying the multiplication factor. 
+
+In addition an attempt to use ace_conditions has been implemented to get rid of the lockfiles 
+all together and further improve the response time. (LockMethod == 1)
+There are still some stability issues in the release version. 
 
 == Implications ==
@@ -59 +60 @@
 For example when using a meta tiling factor of 4, 15 tiles will wait while the meta tile is rendered
 and sliced up. A most efficient locking scheme will have significant effect on this behaviour.
-
 
 == Test Plan ==
@@ -67 +67 @@
 == Issues ==
 
-There are extra tiles calculated to fill up the grid of the meta tiles. They are empty small and don't take long to compute. Any algorithm to avoid that would cause a lot of extra complications due to the loss of the currently orthogonal algorithm. This would impact tile generation and locking strategies. So we currently think its not an issue. 
+There are extra tiles calculated to fill up the grid of the meta tiles. They are empty tile and don't take long to compute. Any algorithm to avoid that would cause a lot of extra complications due to the loss of the currently orthogonal algorithm. This would impact tile generation and locking strategies. 
+Using the MgCooker is adding even more empty tiles around the map boundaries. So we currently think its not an issue. 
+
+There seem to be some leaks somewhere which could not be found also with some tools. However, they are small and considering the use case of the metatiling mode - namely filling the tile cache - they might be tolerable.
+
+[[Image(MapGuideMemoryMetatilingLockfiles.png)]]
+
+[[Image(MapGuideMemoryNoMetatiling.png)]]
 
 == Funding/Resources ==
@@ -75 +82 @@
 == Sandbox ==
 
-http://trac.osgeo.org/mapguide/browser/sandbox/rfc90 OBSOLETE Due to many trunk changes
 http://trac.osgeo.org/mapguide/browser/sandbox/rfc90.2  branched from Rev 5924 and merged in changes
+
+so http://trac.osgeo.org/mapguide/browser/sandbox/rfc90 is now OBSOLETE