Episodes

  • Why Write-Ahead Logging Is Critical for Database Durability

    Why Write-Ahead Logging Is Critical for Database Durability
    Jul 28 2026
    Lucas and Luna dive into write-ahead logging (WAL), the mechanism that ensures your database can survive a power failure without losing data. They explain how PostgreSQL, Oracle, and SQL Server implement WAL, the performance trade-offs of synchronous vs asynchronous commit, and how checkpointing keeps the log from growing forever. A practical breakdown of a core ACID property. #WriteAheadLogging #DatabaseDurability #CrashRecovery #PostgreSQL #Oracle #SQLServer #TransactionLog #DatabaseInternals #ACID #GroupCommit #Checkpointing #SynchronousCommit #AsynchronousCommit #DatabaseTech #FexingoBusiness #BusinessPodcast #Technology #DataStorage Keep every episode free: buymeacoffee.com/fexingo
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    6 mins
  • Why Database Partition Pruning Cuts Query Time Dramatically

    Why Database Partition Pruning Cuts Query Time Dramatically
    Jul 27 2026
    Partition pruning is one of the most effective yet underappreciated optimizations in modern databases. In this episode, Lucas and Luna explore how PostgreSQL and BigQuery use partition pruning to reduce a full-table scan of a year's data down to just a single month. They walk through real-world numbers: a 12x reduction in data scanned, and a query that drops from 45 seconds to under 4. Along the way, they discuss how to design partition keys, what happens when pruning fails, and why even cloud data warehouses rely on this technique to keep costs low. A must-listen for anyone running analytical queries on large partitioned tables. #Database #PartitionPruning #QueryOptimization #PostgreSQL #BigQuery #DataEngineering #SQL #Performance #Analytics #Tech #FexingoBusiness #BusinessPodcast #DatabaseTips #DataWarehouse #CloudComputing #CostOptimization #LucasAndLuna #DatabaseTech Keep every episode free: buymeacoffee.com/fexingo
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    9 mins
  • Why Database Merge Joins Beat Hash Joins for Sorted Data

    Why Database Merge Joins Beat Hash Joins for Sorted Data
    Jul 27 2026
    In this episode of Database Tech with Fexingo, Lucas and Luna explore a common yet overlooked optimization: why merge joins can outperform hash joins when both input tables are pre-sorted. Using a concrete PostgreSQL example with a 10-million-row join, they break down the trade-offs in memory pressure, CPU cache behavior, and disk spill avoidance. Lucas argues that modern optimizers often underestimate the cost of building and probing hash tables, especially when the data is physically ordered by an index. They discuss real-world scenarios where switching to a merge join yielded a 4x speedup, and why leaving hints can help. The conversation also touches on the importance of understanding your data's physical order and how tools like EXPLAIN can expose suboptimal plans. Whether you're tuning SQL queries or designing schema, this episode offers a practical look at join algorithm selection. It's a must-listen for database engineers and data analysts looking to squeeze more performance from their queries without hardware upgrades. #Database #MergeJoin #HashJoin #QueryOptimization #Performance #SQL #PostgreSQL #SortMerge #Indexing #OLTP #JoinAlgorithms #MemoryManagement #DiskSpill #DatabaseTech #FexingoBusiness #BusinessPodcast #Tech #DataEngineering Keep every episode free: buymeacoffee.com/fexingo
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    7 mins
  • Why SQL Window Functions Outperform Self-Joins

    Why SQL Window Functions Outperform Self-Joins
    Jul 26 2026
    In this episode of Database Tech with Fexingo, Lucas and Luna break down a real-world query optimization: replacing a self-join with a SQL window function to compute running totals. They discuss how window functions like ROW_NUMBER, RANK, and LEAD reduce query time from seconds to milliseconds by eliminating multiple table scans. Lucas explains the OVER clause, partitioning, and ordering, and contrasts with subquery alternatives. They cover when window functions shine (analytics, rankings, moving averages) and when traditional joins might still be better. This episode includes a concrete example from a client where a 12-second query dropped to under a second. Ideal for data engineers, analysts, and SQL developers looking to improve query performance and code readability. #SQL #WindowFunctions #QueryOptimization #DataEngineering #Performance #SelfJoin #Subquery #PostgreSQL #MySQL #Snowflake #RunningTotal #Analytics #DatabaseTech #Technology #FexingoBusiness #BusinessPodcast #Engineering #DataAnalytics Keep every episode free: buymeacoffee.com/fexingo
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    7 mins
  • Why Time-Series Data Needs Downsampling Not Raw Storage

    Why Time-Series Data Needs Downsampling Not Raw Storage
    Jul 26 2026
    Episode 132 of Database Tech with Fexingo dives into a common but costly mistake: storing every raw time-series data point forever. Lucas and Luna examine a smart-meter company collecting one-minute readings from 10,000 meters, producing 5.2 billion data points per year. They break down the storage costs, query slowdowns, and why downsampling to hourly aggregates preserves insight while slashing infrastructure bills. The conversation covers retention policies, downsampling strategies (average, min, max, count), and real-world implementations using InfluxDB and TimescaleDB. A must-listen for engineers managing IoT, monitoring, or any time-series pipeline. #TimeSeries #Downsampling #DataStorage #Database #InfluxDB #TimescaleDB #IoT #DataRetention #Aggregation #Performance #CostOptimization #SmartMeter #DataEngineering #Technology #FexingoBusiness #BusinessPodcast #DatabaseTech #SQLNoSQL Keep every episode free: buymeacoffee.com/fexingo
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    8 mins
  • Why Database Schema Changes Need Online Migration Not Downtime

    Why Database Schema Changes Need Online Migration Not Downtime
    Jul 25 2026
    Most teams still schedule maintenance windows to add a column or change a table schema, but in production databases with millions of rows, those windows can stretch into hours of downtime. This episode explains why online schema migration tools like gh-ost and pt-online-schema-change are the safer, faster alternative. Lucas walks through the trigger-based and binlog-based approaches, compares lock vs. non-blocking strategies, and breaks down a real case: how a mid-size e-commerce company cut a 4-hour migration to 15 minutes with row-based replication and asynchronous shadow tables. Luna asks the critical questions about rollback safety and performance impact during the copy phase. No clickbait, just the architecture behind zero-downtime schema changes. #DatabaseSchemaMigration #OnlineMigration #MySQL #ghost #ptOnlineSchemaChange #ZeroDowntime #DataMigration #DatabaseOperations #SQL #NoSQL #TechPodcast #DatabaseEngineer #ProductionDatabase #SchemaChange #TechTalk #FexingoBusiness #BusinessPodcast #DatabaseTech Keep every episode free: buymeacoffee.com/fexingo
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    8 mins
  • Why Database Bloom Filters Defeat Expensive Disk Seeks

    Why Database Bloom Filters Defeat Expensive Disk Seeks
    Jul 24 2026
    Episode 130 dives deep into a single database index technique—the Bloom filter—and shows how it saves millions of disk seeks per second. Lucas explains how a probabilistic data structure with zero false negatives can check whether a key exists without touching storage, using an in-memory bit array and a handful of hash functions. He walks through the classic use case: Apache Cassandra's bloom_filter_fp_chance setting, where a 1% false-positive rate reduces wasted I/O by 99%. Luna probes the trade-off: memory vs. accuracy, and why PostgreSQL's Bloom index extension only makes sense for wide, low-cardinality columns. Together they unpack the math behind optimal hash-count (roughly 7 hash functions per element for a 1% false-positive rate) and why the real win isn't query speed but storage-amplification reduction. A concrete episode for anyone who's ever watched an index scan stall on spinning rust or even SSD latency spikes. #BloomFilter #DatabaseIndexing #ProbabilisticDataStructures #ApacheCassandra #PostgreSQL #DiskSeek #StorageAmplification #HashFunctions #FalsePositiveRate #ReadPathOptimization #LSMTrees #CassandraTuning #bloom_filter_fp_chance #Technology #FexingoBusiness #BusinessPodcast #DataEngineering #DatabaseTech Keep every episode free: buymeacoffee.com/fexingo
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    8 mins
  • Why Database Cursor Fetching Needs Pagination Not Streaming

    Why Database Cursor Fetching Needs Pagination Not Streaming
    Jul 23 2026
    Lucas and Luna dig into why database cursors cause memory blowups when naive streaming is used instead of proper pagination. Using a real-world example of a Postgres query that crashed an analytics dashboard by fetching 2 million rows at once, they explain the mechanics of server-side cursors, client-side buffering, and why LIMIT/OFFSET is not the answer. The episode walks through a concrete fix: using keyset pagination with a stable sort to avoid the O(n) cost of offset skips. Listeners learn one practical pattern to prevent runaway memory in production data pipelines. #DatabaseCursors #Pagination #Postgres #QueryPerformance #DataEngineering #SQL #KeysetPagination #CursorFetching #MemoryManagement #AnalyticsDashboard #BackendPerformance #TechDeepDive #DatabaseOptimization #StreamingData #Technology #FexingoBusiness #BusinessPodcast #DatabaseTechWithFexingo Keep every episode free: buymeacoffee.com/fexingo
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    7 mins