Tag
statistics
- Aug 27, 2026 Power, the Minimum Detectable Effect, and the Cost of Repeated Looks How sample size is determined by the smallest effect worth detecting rather than by convenience, why peeking at a running experiment inflates false positives, and what sequential designs cost in exchange. performance engineering
- Jun 2, 2026 Phi Accrual Detectors: Turning Inter-Arrival Samples into a Continuous Suspicion Level How a detector fits a distribution to observed heartbeat gaps, converts the current gap into a probability that the peer is dead, and why the exponential form of that probability is what makes a threshold portable. distributed systems
- Nov 18, 2025 Selectivity Estimation from Histograms and Most-Common-Value Lists How a single-column statistic turns a predicate into a row count, why equidepth buckets are chosen over equiwidth, and where the estimate fails for correlated columns. databases
- Oct 16, 2024 Confidence Intervals for the Difference Between Two Benchmark Runtimes Why two overlapping intervals can still hide a real difference, how the standard error of a difference is computed from paired or independent samples, and what a ratio estimate needs before it is trustworthy. performance engineering
- Jul 12, 2024 Join Cardinality and Where the Containment Assumption Fails How equality joins are estimated from distinct-value counts, why the uniform-frequency assumption collapses on skewed keys, and how the error compounds across a chain of joins. databases
- Jan 9, 2024 Distribution-Free Comparison When the Data Is Not Normal What rank tests actually test, how permutation and bootstrap procedures produce intervals on a benchmark difference without assuming a shape, and where each method loses power. performance engineering
- Aug 7, 2023 Sampling Error, Skid, and How Many Samples a Profile Needs Why a profile is a binomial estimate, how instruction skid biases samples toward long-running instructions, and what confidence a given sample count actually supports. observability
- Apr 27, 2023 Seasonality and the Limits of Static Alert Thresholds How diurnal and weekly cycles defeat a fixed threshold, what a seasonal baseline measures against, and why differencing a series amplifies its noise in proportion to the step size. observability