[GRASS-user] SQLITE db locking problem

[Mark Wynter]

Hi everyone

I’m having issues with SQLITE as the db driver - I encounter this BUSY warning.  Only occurs when patching a particular map, in this case  “temp_nbt_cleaned" which is the largest of the datasets being patched.  If I work with smaller datasets, it works fine.  Pre-patching, SQLITE DB size is only 170MB.

I’ve come across various threads reporting something similar with db locking.  But couldn’t find a resolution.
I’m running grass70 on Centos65, hosted on AWS..  SQLite is version 3.6.23.1 

This is the error message.

GRASS 7.0.0svn (nodeclean):/var/tmp > v.patch -e input=temp_t_cleaned,temp_b_cleaned,temp_nbt_cleaned out=temp_patched
Patching vector map <temp_t_cleaned>...
Patching vector map <temp_b_cleaned>...
Patching vector map <temp_nbt_cleaned>...
WARNING: Busy SQLITE db, already waiting for 10 seconds…
WARNING: Busy SQLITE db, already waiting for 20 seconds…
etc
etc

I encounter no problems patching the maps, including “temp_nbt_cleaned" if I use PG db driver, or DBF driver.

building topology for vector map <temp_patched at PERMANENT>...
Registering primitives...
1860504 primitives registered
9027638 vertices registered
Building areas...
 100%
0 areas built
0 isles built
Attaching islands...
Attaching centroids...
 100%
Number of nodes: 1457611
Number of primitives: 1860504
Number of points: 0
Number of lines: 1860504
Number of boundaries: 0
Number of centroids: 0
Number of areas: 0
Number of isles: 0
Intersections at borders will have to be snapped
Lines common between files will have to be edited
The header information also may have to be edited
v.patch complete. 3 vector maps patched


I’m more than comfortable using PG in the backend, but I find v.out.postgis too slow when exporting the resultant dataset back to postgis (possibly because its simultaneously trying to read and write to the same db). I haven’t tested whether v.out.ogr quicker than v.out.postgis.

Any assistance resolving the SQLite issue would be greatly appreciated.

Kind regards

Mark

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