Everyone can self-identify as they like, the real ones in this case are easy to spot just asking them to tell you some stories of absurd problems they solved. They always have a boatload of war stories.
Tiny example: I joined a company and a nightly process was data import. The import was starting to take longer than 25 hours, threatening the “daily” aspect, and on the verge of causing logistical problems because of this.
The problem had been looming for months and has taken more time from multiple folks than anyone anticipated, impacting other projects’ timelines.
It wasn’t on my plate, but I overheard others talking about it. I took a look, and spent a couple days testing out ideas. I got a 25 hour process down to 30 minutes. Had to do it myself first to prove it, because just making suggestions to the “experienced” folks was dismissed with “that’s not how this works, you don’t understand”. After I got it to 30 minutes, the same folks “optimized” my process down to about 25 minutes, then didn’t overly acknowledge the approach I’d used to make this manageable again.
I’ve had pushback on this story like “well, there was probably something you’re leaving out. Everyone likes to think their contribution is the most important, but things are a team effort. We’re not all superheroes”.
If you ask for war stories, be prepared for dailywtf-level stuff sometimes.
That's how people that give no contributions whatsoever would reply, I think. The pattern "identify thing that takes too long, local expert says it's unfixable and you don't understand, you fix it in a few hours, local expert downplays" is VERY common, but until the one controlling the budget is aware of reality I'm ok with it. And in those cases you see the good people because they get excited and want to help improve more things.
* Create new table on disk.
* Create temp table in RAM.
* Start chunked import.
* Import 50k rows in to temp table.
* Dump temp table to new table.
* Clear temp table.
* Import next 50k rows.
* Repeat.
* Drop old table, rename new table on disk to regular name
Each row being imported was updating indices. Just removing indexes, then importing, did speed it up, but not as dramatically. Importing most to RAM table, then chunking to the final table. That was a core key.
I'd indicated early on "let's try temp memory tables". It was dismissed ("we tried that" and also "what's that?"). So I did my own tests, and it was pretty dramatic.