[mapserver-users] Speeding up WFS paging with Spatialite and GeoPackage

[Rahkonen Jukka (MML)]

Even Rouault wrote:
Re: [mapserver-users] Speeding up WFS paging with Spatialite and GeoPackage


On mardi 20 décembre 2016 13:07:27 CET Rahkonen Jukka (MML) wrote:

> https://www.postgresql.org/docs/9.1/static/sql-declare.html



In the PostGIS case (I mean not through OGR PG driver), OFFSET and LIMIT are also used:

https://github.com/mapserver/mapserver/blob/branch-7-0/mappostgis.c#L1968



Postgres cursors can be used when you have a persistent connection and iterate through the result set (that's what the OGR PG driver does in its GetNextFeature() implementation). But WFS is state less, so that couldn't be used. Or that would require special code, that could only work in fastCGI with defered connection closing, and likely some timeout mechanism to be able to ditch cursors no longer being used, to be able to reuse a Postgres iterator among several identical queries that would differ only by their STARTINDEX.



All right, now I understand much better this GDAL ticket https://trac.osgeo.org/gdal/ticket/6713 and the 2-3 times faster response time with tailor made system that is utilizing "next".



-Jukka-


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