postgis-mvt-server returns mvt vector tiles.

The creation of a tile can take considerable database query time, especially if the same tile is requested multiple times. This can be overcome by creating a disk-cache.

There are many external disk-caching possibilities, for instance Nginx caching, but a postgis-mvt-server internal cache can take into account the specific aspects of vector tile caching.

• a separate cache (sub-directory) per data source. If the datasource is removed or updated, the corresponding cache can be easily removed or reset.
• option to configure the cache to cache lower zoom levels only. Lower zoom levels contain more data and are requested much more often. Therefore it is extra advantageous to cache those levels. More detailed data could skip the cache and be retrieved from the database directly. This would make the tile-service both fast and deliver up-to-date detailed data.

Hi. I trying to use this server, but unfortenutely got the follwing error:

Error executing database query: function st_asmvt(unknown, integer, unknown, record) does not exist error: function st_asmvt(unknown, integer, unknown, record) does not exist
at Connection.parseE (/home/bulaj/projects/postgis-mvt-server/node_modules/pg/lib/connection.js:567:11)
at Connection.parseMessage (/home/bulaj/projects/postgis-mvt-server/node_modules/pg/lib/connection.js:391:17)
at Socket. (/home/bulaj/projects/postgis-mvt-server/node_modules/pg/lib/connection.js:129:22)
at emitOne (events.js:96:13)
at Socket.emit (events.js:188:7)
at readableAddChunk (_stream_readable.js:176:18)
at Socket.Readable.push (_stream_readable.js:134:10)
at TCP.onread (net.js:547:20)

What can be wrong? Pg 10 + PostGIS 2.4

SELECT PostGIS_full_version();

POSTGIS="2.4.1 r16012" PGSQL="100" GEOS="3.6.0-CAPI-1.10.0 r0" PROJ="Rel. 4.9.3, 15 August 2016" GDAL="GDAL 2.2.2, released 2017/09/15" LIBXML="2.9.3" LIBJSON="0.11.99" LIBPROTOBUF="1.2.1" TOPOLOGY RASTER
(1 row)

Many vector datasets are optimized for particular zoom-levels. A feature to automatically select a source dataset depending on the requested zoom-level would allow postgis-mvt-server to deliver optimized vector tiles for a larger range of zoom levels