[bob457]

I always see people say how great gmail search is, as does the author in this article.

This befuddles me.

Gmail search often leaves out results I know are there, and sometimes comes up erroneously empty. I can verify this, because I store my emails offline. They are indexed by notmuch. I find notmuch to be not only faster than gmail search, but far more thorough: notmuch gives me hits that gmail skips.

[partomniscient]

My guess they got so many performance gains by conceding a bit of data integrity or search accuracy or replication accuracy or something. Not sure whether it was accidental or on purpose but it seems a persistent behaviour.

Running the same very low result count returning search queries in other parts of googles data sprawl sometimes returns different sized outputs. There's more than one reason they stopped telling you how many search results there were, my guess is consistent inconsistencies is another.