Re: [xml] Constraint validation for huge documents

[Stefan de Konink <stefan konink de>]

Hi Nick,


Thanks for your reply. It does have a noticeable impact, while having 
compiled libxml2-git yesterday, I oversaw it.


With the single constraint file;
libxml2-2.9.10
User time (seconds): 90.81
Elapsed (wall clock) time (h:mm:ss or m:ss): 1:31.60

libxml2-git
User time (seconds): 49.57
Elapsed (wall clock) time (h:mm:ss or m:ss): 0:50.57

With the full constraint file;
libxml2-2.9.10
Not completed after 1 hour 30 min

libxml2-git
User time (seconds): 900.60
Elapsed (wall clock) time (h:mm:ss or m:ss): 15:02.87


Yesterday I wrote a custom validator in lxml for key/keyref and unique 
constraints. It basically validates syntactically using the normal libxml2 
code, and then fetches all constraints (this might be a shortcut), creates 
a hashset per constraint. This process can be executed in parallel per 
constraint. If taking into account the number of elements (by heuristics, 
if the same xsd is used over time) parallelism can be ensured over a longer 
period.

With multithreading (8):
User time (seconds): 1136.37
Percent of CPU this job got: 388%
Elapsed (wall clock) time (h:mm:ss or m:ss): 4:57.09

Without multithreading:

User time (seconds): 709.82
Percent of CPU this job got: 99%
Elapsed (wall clock) time (h:mm:ss or m:ss): 11:52.15



I assume that the optimisation currently present in git is a serious 
improvement. Sure, it is still not 'perfect' but I think that doing the 
validation in parallel might be something worthwhile to explore.

--
Stefan