Critical Tegola bugs

[pnorman]

Tegola has some critical bugs that prevent a number of essential things in the style. This meta-issue is to track them

Critical bugs

These are serious enough to prevent release, and do not have acceptable workarounds.

SQL type sniffing

• Tegola uses LIMIT 1 to look at a row (error fetching geometry type for layer go-spatial/tegola#320). This prevents ordering in the roads layer.
• function(!ZOOM!) and !ZOOM! < n cause syntax errors (!ZOOM! substitution error go-spatial/tegola#343). This prevents filtering by area depending on zoom.

Output bugs

• Missing water polygon (Missing water polygon go-spatial/tegola#348)

Major

These don't prohibit release, but cause major problems or have bad workarounds

Output bugs

• Geometry corrupted by simplification (Geometry corrupted by simplification go-spatial/tegola#341).
• Tiles missing data when multiple rows have same id (Tiles missing data when multiple rows have same id go-spatial/tegola#337) is part of the cause of the extra sub-select all the queries have.

Major enhancements

These make something which is currently difficult or messy significantly better.

• Merging multiple layers (Merging multiple layers go-spatial/tegola#127). This would eliminate most of the UNION ALLs
• Don't require ID field for layers (Don't require ID field for layers go-spatial/tegola#338)
• Best practices for deploying Tegola (Best practices for deploying Tegola go-spatial/tegola#356) is not blocking code release, but blocks any public demo.