sqlite plugin - vtable constructor failed

[talaj]

Getting following error on older distributions like Debian Wheezy or Ubuntu Precise with this test: #2461.

"text-data-binding-500-500-1.0" with agg... ✘ (RuntimeError('Sqlite Plugin: \'vtable constructor failed: idx_circular_layer_geom\' (/mapnik/tests/visual_tests/
styles/../data/text-data-binding.sqlite)\nFull sql was: \'SELECT geom,id,[alignment],[color1],[color2],[color3],[double],[placement],[text1],[text2] FROM circu
lar_layer WHERE id IN (SELECT pkid FROM "idx_circular_layer_geom" WHERE xmax>=-1 AND xmin<=1 AND ymax>=-1 AND ymin<=1)\'',))

[talaj]

I found where the problem is finally! Shared cache in SQLite datasources should not be used with SQLite prior to 3.7.15. There are concurrency issues, see "Bug fix: Avoid various concurrency problems in shared cache mode.": https://www.sqlite.org/releaselog/3_7_15.html
I was comparing SQLite 3.7.15 with 3.7.14. The 3.7.14 fails on vtable constructor failed , 3.7.15 works fine.
I would update version to 3.7.15 in https://github.com/mapnik/mapnik/blob/master/plugins/input/sqlite/sqlite_connection.hpp#L58

[springmeyer]

Aha! nice find. Please feel free to commit that change and close this up.

[springmeyer]

Would be worth backporting to 2.3.x as well I think. You agree?