← Back to Martin Tile Server roadmap
Together with the Technical University of Munich’s chair of Big Geospatial Data Management, we are currently working on a thesis where the next generation of vector tile performance from tile servers could come from:
- At the minimum, the outcome of this initiative will be a documentation page detailing which aspects of vector tiles are not improving performance and why.
- At best, the outcome will be a new optimised mode for serving styles and the data in a co-optimised fashion.
Here are the optimisations that are currently planned for evaluation:
| optimisation | requirement | description (technique) |
|---|---|---|
| dead source elimination | - | remove impossible or hidden data-sources or style-layers (dead code elimination) |
| expression order optimisation | sampling | optimise the order of reorderable-expressions (like match) (selectivity analysis) |
| expression kind optimisation | - | rewrite expensive operators with more performant forms (operator selection) |
| constant folding | full scan | replace constant style expressions or predicates with literal values (constant folding) |
| filter reordering | sampling | optimise style filter order (like any, all, match, case) (selectivity analysis) |
| metadata refinement | full scan | more accurate {min,max}_zoom metadata based on the data, filters, and impossible styling conditions (think: opacity=0 after zooming out) (no exact match) |
| tile shaving | - | only encodes the exact data that a style would actually look at (no exact match) |
| transparent reencoding | - | reencode tiles into a different tile specification on the fly (storage format) |
| compression optimisation | - | compress tiles more aggressively or with a different compression algorithm (no exact match) |
| prewarming caches | - | make sure that sprites and fonts are in an in-memory cache (prefetching) |
| minimum sprite-set mining | - / full scan | some styles may permit to statically know which sprites will be used. For others, one might need to do a full table scan to gather this statistic. (no exact match) |
| data layout optimisation | - | for dynamic databases, reorganise tile data for access pattern (storage layout) |
| overlap reduction | - | for some layers like roads or pois at the higher zoom levels overlap is common. If one knows the style redundant data can be removed (storage layout) |
| static generation | static source | extract semantics and generate a new, optimal static instruction set for constructing the tile database |