DOC: doc build on travis timing out

[jorisvandenbossche]

For some reason, the doc build on travis started timing out since a couple of commits. See eg https://travis-ci.org/pandas-dev/pandas/builds/206994038. It just takes so long it hits the "The job exceeded the maximum time limit for jobs, and has been terminated." (around 50 min), while before the doc build on travis took between 20 and 30 min.

It started with the FrozenList changes (37fe2c4), but I don't see how that could cause this.

I also don't directly see any changes in the environment that is created on travis to build the docs (eg both using sphinx 1.5.1, no change there).

[jreback]

hmm that is odd. we have certainly had occasional failures but nothing like this.

[jorisvandenbossche]

I also see this locally as well. It seems to be keep hanging on building the timeseries.rst file.
EDIT: no, not specifically this file, also with others. So reading in general is a lot slower.

There was no change in the IPython version before and after this started (both 5.3.0), so also not caused by the ipython directive.

[jorisvandenbossche]

So my local build just finished and it took 92 min.
If I reset the last 7 commits (so up to including the Frozenlist changes), it takes 17 min (exact same environment, not even a rebuild of pandas)

I tried few benchmarks, but don't see any direct changes on those between the two versions.

[jreback]

https://travis-ci.org/pandas-dev/pandas/jobs/207696130

looks like it built, but some issue in reshape

[jreback]

so I think this is somehow constantly doing import matplotlib as plt but not really sure why / how this happens. maybe its something in the import cycle.

[gfyoung]

Let's watch this, but this hasn't been an issue for awhile.