Making Heroku CI (almost) as fast as running Rspec locally

Once Heroku support showed us how to specify the Postgres version for in-dyno Postgres in our app.json we re-ran our Rspec rspecs and were pleasantly surprised how fast they ran. (Specifying Postgres 9.6 seems to be required for Rspec for a Rails 4.2.11 app; using the default Postgres 10 causes errors related to the change of the increment_by field in P 10)

 Mac OS XHeroku CI "M" dynoHeroku CI "M" dyno
IN-DYNO postgres
Heroku CI "L" dynoHeroku CI "L" dyno
IN-DYNO postgres
Dyno cost/hour$0.34$0.34$0.68$0.68
Run Time5:5359:0013:27 !!!31:438:03 !!!
Heroku cost$ 0.34$ 0.08$0.36$0.09

The “trick” to specifying the Postgres version for in-dyno Postgres is to use an environment variable. If this is documented anywhere we could not find it, so perhaps this will be helpful to someone else:

In order to change the Postgres version for the in-dyno add-on you’ll need to create a new environment variable in your app.json like this:
  “environments”: {
    “test”: {
      “addons”: [“heroku-postgresql:in-dyno”],
      “env”: {
          “value”: “9.6”



Heroku Deploys via Github are not faster than using git push

While we did not expect to see any difference, we did confirm that our 10 minute deploys to a Heroku staging server typically take the same amount of time whether we use the old git push vs Github integration.

We did not test whether a deploy with significant new data (a ton of new images added to the repo for example) was materially faster from Github.

Heroku CI is remarkably slow, but half as slow if you use the largest dyno type

UPDATE: using in-dyno postgres puts Heroku CI on par with running Rspec locally!

Experimenting with using Heroku CI for a Rails app, we were a little surprised just how slow Rspec specs run.

As you can see however the runtime cost is about the same since the largest dyno performance-l costs twice as much as the default dyno used by Heroku CI.

Unfortunately, we cannot test using in-dyno Postgres since Heroku does not seem to offer a way to specify the Postgres version for in-dyno instances.

 Mac OS XHeroku CI "M" dynoHeroku CI "L" dyno
Dyno cost/hour$0.34$0.68
Run Time5:5359:0031:43
Heroku cost$ 0.34$0.36

Next Step: If we can get parallel tests to run, it will be interesting to see if the overall runtime (and cost) remains constant so we can shorten the test to say 2 minutes by running 16 dynos.

If so that may be GREAT news for using Heroku CI vs Travis CI or Circle CI, whose fixed monthly cost is HUGE for even a few concurrent instances.

4 Most Remarkable Shortcomings of Apple Watch Series 4 (e.g., why I returned it)

That’s a lie. It’s NOT an AirPlay source:

Ooops. Even on version 5 of Watch OS,
Apple forgot to ‘mirror’ your iPhone’s

default alert setting to your Watch, or provide
any other way to add an alert to an appointment.

For someone who uses Macs and iPads and iPhones, there’s a lot to like about the Series 4 Apple Watch (GPS + Cellular, watch OS 5.1.2).

But I returned mine to the Apple Store after only 3 days because:

  • The Deal Killer: Cannot create appointments with “alerts” – if you use the Watch to create a Calendar appointment, there is no way for the Watch to add an alert, such as an alert 30 minutes beforehand. So your appointments created with a Watch behave differently than the ones you created with your iPhone. (If you create an appointment via an iPhone, or an iPad, or a Mac you can set a default alert, but not with the Watch.) This was confirmed today by Apple Support who escalated the issue to engineering.
  • Calendar displays only current month. Of the many bone-headed things Apple has done in the post-Jobs era, a Calendar app that will not display months other than the current month deserves special mention. If you display the month-at-a-glance calendar, and turn the scroll knob, or swipe, the Watch displays… the same (current) month.
  • No 5 GHz Wifi support  – had to dumb-down my home wifi network to 2.4GHz for the Watch to connect correctly to the iPhone, even though it said it was connected it wasn’t connected to the iPhone via Wifi. Apple documentation is silent about the need to dumb-down your Wifi to 2.4GHz… One symptom is ridiculously slow music syncing when adding playlists to your watch if your iPhone connected via 5GHz and your watch connects via 2.4GHz… but the iPhone offers NO way to “see” what Wifi speed your iPhone is connected, so good luck debugging this.
  • No Airplay support – despite offering an “Airplay” option right on the Control Center when selecting audio output, the Watch is NOT on Apple’s list of Airplay audio sources. Confirmed with Apple Support on lengthy call: if you have a nice stereo connected to an Apple TV, no, you cannot stream audio to the Apple TV’s sound system. So the “Airplay” option on the Watch is a lie… iPhone and iPad and Mac Airplay options DO connect to my Apple TV (audio and/or video) the Apple Watch will not show an AppleTV among the audio destination options. (I thought perhaps it was because mine was a 3rd Gen AppleTV but Apple Support said no version of AppleTV can play music from a Watch.)
  • BONUS Shortcoming: No Phone or Messages quick-launch option for the new Infographic faces. Oddly, the fancy new faces do not support the two most important options (which they call complications)… no phone and no messages.