Disabling Slack Indexing Seems to Improve Spotlight Performance on iOS twitter.com

I’ve generally had pretty good luck with Spotlight on iOS, but I’ve long noticed that results are delayed or nonexistent after not using it for a little while, particularly if I haven’t rebooted my phone recently. I thought I was losing my head a little bit, until I found a tip on Twitter from Anand Iyer‏:

Settings > General > Spotlight Search > toggle Slack off

Just like that, Spotlight seems to be running quickly again. Every query I’ve tried is fast and reliable, even if I don’t use my phone for a while. I don’t know why Slack, in particular, seems to make Spotlight perform so poorly — other apps surely index thousands of messages and require network lookups to complete — but this one weird trick seems to make Spotlight performance issues disappear.

Update: John Gruber:

Sounds like there might widespread problems with Spotlight indexing on iOS 10, because a bunch of readers have written to say they have the same problem but don’t even have Slack installed.

I’ve seen this Slack trick working for a few other people, so I wonder what the common thread is between those of us with Slack installed and those without. Perhaps there are issues with indexing large numbers of items, or perhaps toggling a setting simply rebuilds the Spotlight cache.

Update: I’ve seen reports that 10.3.2 fixes this bug altogether. Daniel Shockley says that he improved Spotlight performance by toggling languages, which makes me think that it is — or was — a bug that can be worked around by clearing a cache.