“Xiao Zhang, why hasn’t this SQL query finished after 5 minutes?”
“I checked this data yesterday; why does it take so long today?”
“The morning meeting is about to start, and the report is still loading…”

Do these complaints sound familiar? As a DBA or data engineer, you’ve likely experienced the awkward moments of being “swarmed” by users. Faced with repetitive query demands, the system acts like a “forgetful patient,” recalculating every time, which is truly frustrating.