pgsql2shp error on streaming replica: cannot execute CREATE TABLE AS in a read-only transaction

[dfuhry]

pgsql2shp when run against a PostgreSQL streaming replica gives output:

Initializing... 
Error executing user query: ERROR:  cannot execute CREATE TABLE AS in a read-only transaction

because streaming replicas are read-only and cannot execute mutable queries like CREATE TEMP TABLE in the ShpDumperOpenTable function in pgsql2shp-core.c.

A fix would be to instead of creating a temp table, PQexec the query, read data types from the PGresult, and compute field widths by scanning the result, something like how psql does in the printQuery and print_aligned_text methods in Postgres' psql/print.c.

[dfuhry]

A related ticket is #2045 which laments that pgsql2shp fails when the exporting database user does not have permission to create a temp table, and proposes a GSoC.

[robe]

dfuhry sounds good. The problem is that no one in PostGIS dev group is interested in mentoring except possibly strk and even he I don't think is all that interested.

You wanna be a mentor :)

I've changed title of GSOC page to 2014 since all these are still open and Voronoi is partially closed.

http://trac.osgeo.org/postgis/wiki/GoogleSummerCode

[robe]

I put us live on the OSGeo page. ​http://wiki.osgeo.org/wiki/Google_Summer_of_Code_2014_Ideas#OSGeo_Foundation_member_projects

I guess if any students are interested in pgsql2shp stuff I know it well enough to fill somewaht comfortable mentoring it and we do have other tickets for that I'll tag.

[robe]

As noted this is a duplicate of #2045