| | 1 | = !MapGuide RFC 64 - Enabling strict exception handling for tile generation = |
| | 2 | |
| | 3 | This page contains an change request (RFC) for the !MapGuide Open Source project. |
| | 4 | More !MapGuide RFCs can be found on the [wiki:MapGuideRfcs RFCs] page. |
| | 5 | |
| | 6 | |
| | 7 | == Status == |
| | 8 | |
| | 9 | ||RFC Template Version||(1.0)|| |
| | 10 | ||Submission Date||(08.05.2009)|| |
| | 11 | ||Last Modified||(UV Wildner) [[Timestamp]]|| |
| | 12 | ||Author||(UV Wildner)|| |
| | 13 | ||RFC Status||(draft)|| |
| | 14 | ||Implementation Status||(discussion needed)|| |
| | 15 | ||Proposed Milestone||(2.1)|| |
| | 16 | ||Assigned PSC guide(s)||(when determined)|| |
| | 17 | ||'''Voting History'''||(vote date)|| |
| | 18 | ||+1|||| |
| | 19 | ||+0|||| |
| | 20 | ||-0|||| |
| | 21 | ||-1|||| |
| | 22 | ||no vote|||| |
| | 23 | |
| | 24 | == Overview == |
| | 25 | |
| | 26 | Currently an exception thrown during the stylization code for a tile is caught and ignored. |
| | 27 | This can lead to partially incomplete tiles which are hard to detect as no error information is passed via the API. |
| | 28 | Even worse the tile is kept in the tilecache! |
| | 29 | |
| | 30 | == Motivation == |
| | 31 | |
| | 32 | Originally, the mapguide server has been designed as an interactive map generation system. |
| | 33 | For the important use case of rendering tiles and filling the tile cache incomplete tiles are undesirable. |
| | 34 | in particular keeping the faulty tile in the cache seems the wrong way to go. |
| | 35 | |
| | 36 | == Proposed Solution == |
| | 37 | |
| | 38 | A switch in serverconfig.ini should be introduced which can change this behaviour on demand. |
| | 39 | e.g. |
| | 40 | HandleRenderingErrors = STRICT |
| | 41 | |
| | 42 | which leaves us room for additional ways to deal with this: |
| | 43 | |
| | 44 | === render a tile with an error message could be === |
| | 45 | |
| | 46 | HandleRenderingErrors = SHOW |
| | 47 | |
| | 48 | === default cases === |
| | 49 | |
| | 50 | HandleRenderingErrors = IGNORE |
| | 51 | |
| | 52 | HandleRenderingErrors = DEFAULT |
| | 53 | |
| | 54 | HandleRenderingErrors = |
| | 55 | |
| | 56 | and ommitting the parameter would change nothing |
| | 57 | |
| | 58 | However I think letting the tile into the cache should be generally prohibited in an exception situation. |
| | 59 | |
| | 60 | == Implications == |
| | 61 | |
| | 62 | NONE |
| | 63 | |
| | 64 | == Test Plan == |
| | 65 | |
| | 66 | Render tiles on a low memory virtual machine which causes memory errors and compare TileCache with different settings |
| | 67 | |
| | 68 | == Funding/Resources == |
| | 69 | |
| | 70 | |
| | 71 | == closed Issues == |
| | 72 | |
| | 73 | NONE |
| | 74 | |
| | 75 | == open Issues == |
| | 76 | |
| | 77 | Does anyone wants to have faulty tiles in the tile cache? |
