Data Science Posts

Using Postgres Constraint Exclusion To Speed Up Time-Window Queries

I ran into a problem that felt almost too dumb to be real: I had “time-window” SQL queries that were slow even when the date range clearly should have...

Aug 16, 2026Read more

Data Science

Debugging Latency Spikes With Kafka Timestamp Skew And Deterministic Replays

The bug that made every dashboard “lie” I ran a real-time analytics pipeline that looked perfect—until I stared at a 5-minute gap every hour where me...

Aug 13, 2026Read more

Data Science

Streaming Quantile Drift With Online Parquet Row Group Fingerprints

The bug I couldn’t explain: “same pipeline” but different answers I ran an AI feature pipeline that reads events from a streaming source, lands them ...

Aug 10, 2026Read more

Data Science

Streaming Late-Event Repair For Clickstream Using Sql Temporal Windows

Why I got obsessed with “late events” in clickstreams I built a real-time clickstream pipeline for a dashboard that updates every few seconds. Every...

Aug 3, 2026Read more

Data Science

Streaming Late-Event Backfills With Event-Time Watermarks In Duckdb

The problem I ran into: “real-time” metrics that mysteriously move backward I was building a small real-time analytics pipeline that computed a roll...

Jul 17, 2026Read more

Data Science

Enforcing Scd Type 2 Integrity For Real Time Feature Store Feeds

Why I got stuck: “the feature went backwards” I was building a real-time feature feed for an AI model—think “latest customer attributes right now”—an...

Jul 9, 2026Read more

Data Science

Building A Real Time Data Freshness Gate With Debounced Heartbeats

The problem I ran into: “Fresh” data that wasn’t actually fresh I was building a real-time analytics feed for an AI feature store. Everything looked ...

Jul 3, 2026Read more

Data Science

Detecting Silent Timestamp Drift In Streaming Sensor Data With Sql And Row-Level Lineage

I got burned by a failure mode that’s weirdly hard to spot: my real-time model didn’t crash, but it started learning from “time-shifted” data. The sen...

Jun 26, 2026Read more

Data Science

Building A Backpressure-Aware Real-Time Feature Store Using Postgres Logical Replication And Kafka

The problem I ran into: “real-time” that wasn’t I built what I thought was a clean real-time analytics pipeline: events flowed into Kafka, a consume...

Jun 25, 2026Read more

Data Science

Optimizing Postgres With Generated Columns For Jsonb Key Existence Filters

The problem I kept running into I was building a real-time analytics pipeline on PostgreSQL, where events came in as `JSONB`. Each event had a paylo...

Jun 5, 2026Read more

Data Science

Predicting Same-Day Checkout Failures With Feature-Arrival Time Windows

I ran into a weird failure mode while building a predictive model for “will this checkout fail today?” The data looked fine in batch, but during real-...

May 5, 2026Read more

Data Science

Building A Scd Type 2 “Event-Time Merge” For Late Arriving Clickstream In Dbt And Snowflake

Building a SCD Type 2 “Event-Time Merge” for Late Arriving Clickstream in dbt and Snowflake The problem that pulled me into this niche is simple: cl...

Apr 22, 2026Read more

Data Science

Taming The “Late-Arriving Dimension” Spike With Sql Window Filters

The problem I chased: a sudden 10x query spike in real-time metrics I hit a performance cliff in a real-time analytics pipeline that joins event dat...

Apr 21, 2026Read more

Data Science

Event-Time Dedupe Drift In Kafka Streams With Late Arrivals

The bug I couldn’t explain: “Same event, different features” I ran a real-time feature pipeline for an AI model and watched accuracy slowly degrade o...

Apr 15, 2026Read more

Data Science

Building A Streaming “Monotonic Timestamp” Guardrail In Kafka Connect

Building a Streaming “Monotonic Timestamp” Guardrail in Kafka Connect A weird class of incidents kept biting me in real-time pipelines: event times ...

Apr 3, 2026Read more