Reduce I/O thrashing during feature ingestion and tiling

2.23.0

• Remove the concept of "separate metadata." Features now always directly reference their keys and values rather than going through a second level of indirection.
• Limit the size of the string pool to 1/5 the size of memory, to prevent thrashing during feature ingestion.
• Avoid using writeable memory maps. Instead, explicitly copy data in and out of memory.
• Compress streams of features in the temporary files, to reduce disk usage and I/O latency

Speed up feature dropping by removing unnecessary search for other small features

2.22.0

• Speed up feature dropping by removing unnecessary search for other small features

Improve label placement to avoid placing labels in polygon holes

2.21.0

• Improve label placement to avoid placing labels in polygon holes

Round coordinates instead of truncating them, for better precision when overzooming

2.20.0

• Round coordinates instead of truncating them, for better precision when overzooming

Set the base zoom for -Bg as part of the --smallest-maximum-zoom-guess logic

2.19.0

• Don't guess an excessively large maxzoom when there is only one feature
• Set the base zoom for -Bg as part of the --smallest-maximum-zoom-guess logic

Fix crash when using tile-join to join an empty pmtiles tileset

2.18.0

• Fix crash when using tile-join to join an empty pmtiles tileset

Add support for pmtiles output format

2.17.0

• Add pmtiles output format

Reduce memory usage when there are large numbers of features

2.16.0

• During tiling, limit the size of the statistics that are kept for -as-needed calculations, because they can get quite large for sources with hundreds of millions of features.

Generate fewer duplicate label points at high zoom levels

2.15.0

• Generate label points in a more straightforward checkerboard, and fewer of them at high zoom levels.

Don't preflight zoom levels for potential as-needed dropping

2.14.0

• Don't preflight each zoom level if one of the as-needed options is specified. Instead, go ahead and write out the tiles, and then clear out the zoom level for another try if necessary.