Large numbers of log statements cause the UI to hang

[Dan Nixon]

The following script demonstrates the problem well:

sample = CreateSampleWorkspace(NumBanks=100, Random=True, XUnit='Energy', XMin=-10, XMax=10, BinWidth=0.1)
symm_out = Symmetrise(Sample=sample, XMin=0.2, XMax=1, Verbose=True)

When run with log level set to information this takes around 30 seconds, on notice or higher it takes around 2.

It seems like the Result Log can't handle large amounts of log statements in a short time and until all of the queued log statements are printed the entire Mantid UI hangs.

[Nick Draper]

This is nothing to do with the volume of logging, but is affected by the logging level. Both in debug and release if the logging level is information or lower (even if you stop the symmetrise algorithm from logging) there is:

1. a freeze of the application (if you try moving a gui window around during processing).
2. a slight slow down in processing despite very little logging actually going on.

However this is not too urgent because:

1. We have only been able to reproduce this with this algorithm so far.
2. In release this algorithm runs in under 2 seconds.

[Stuart Campbell]

This ticket has been transferred to github issue ​11317