LIMIT 50 OFFSET 45000 reads forty-five thousand rows and discards them, which is fine until somebody paginates to the end. The row-value comparison is the part that trips…
A cache that fills, restarts, and refills, with every restart being a period where every request compiles everything. The restart counters are the numbers to alert on and…
A cache entry expiring under load means every request recomputes it at once, and a lock that expires before the computation finishes makes it worse. Two things have…
A COPY rebuilds if any earlier layer changed, even when what it copies is identical — –link breaks that chain. The mechanism is that a linked copy creates…
Nothing in the profile looked slow, and one function accounted for 80 seconds of a 94-second job. Sorting a profile by self time per call finds the slow…
An average response time of 180 ms describing a distribution where a fifth of requests take over a second. The correlation between the slow tail and the valuable…