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Updated OptimizeRenderingWithPostGIS (markdown)

Pete 2016-06-28 16:24:17 +01:00
parent d778967a57
commit 7d2a9e95cc
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OptimizeRenderingWithPostGIS.md

@ -219,7 +219,7 @@ SELECT ST_XMin(ext),ST_YMin(ext),ST_XMax(ext),ST_YMax(ext)
FROM (SELECT ST_Extent(geom) as ext from planet_osm_line) as tmp FROM (SELECT ST_Extent(geom) as ext from planet_osm_line) as tmp
``` ```
...which requires PostGIS to walk the entire result set of the queried table each time the DataSource is used for the first time in a rendering session. There are three parameters available for use ...which requires PostGIS to walk the entire result set of the queried table each time the DataSource is used for the first time in a rendering session. There are three parameters available for use to avoid this process:
### extent_from_subquery ### extent_from_subquery
E.g. `<Parameter name="extent_from_subquery">true</Parameter>` E.g. `<Parameter name="extent_from_subquery">true</Parameter>`