Tab, Shp, Shptree, PostGIS performance

[Erki Saluveer]

Hi

I've been using Minnesota Mapserver for a while with a big success. Though I
haven't understood completely which file formats to read fits best for
Mapserver.

Biggest mystery is shape file. It should be the fastest file format to read,
but it's been the slowest in all my tests.

 

Like one test I made with Mapinfo TAB, ESRI shape, PostGIS database table
and shptree file.

I had at first one MapInfo dataset (33 Mb). To get shape file I translated
it with MapInfo's Universal Translator. From shape file I made qix file with
shptree in depth 8 and using shp2pgsql I created database entry file (I also
indexed postgis table)

 

Then I put together 4 different map files to read these. Test was made with
single and concurrent queries (500 queries for each map file).

The results are as follows:


File Type

Time per request

Time per concurrent request


TAB

78

30


SHP

835

579


SHP with qix

822

580


PostGIS

69

19

* Times are in milliseconds

Why is shape so slow?!? I appreciate any help to find answer to this
question. 

Sincerely,
Erki Saluveer

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