https://www.professionaldev.dev/tags/concurrency/Recent content in Concurrency on Professional developerHugo -- gohugo.ioenMon, 19 Oct 2026 00:00:00 +0000https://www.professionaldev.dev/post/java/mssqlserver/fast_insert_part6/Mon, 19 Oct 2026 00:00:00 +0000https://www.professionaldev.dev/post/java/mssqlserver/fast_insert_part6/ <p>Every strategy we've tested so far — Hibernate, JDBC, Bulk API — pushes data through a single connection. SQL Server handles concurrent writes just fine; the bottleneck is the serial nature of one TCP stream. Split 100k rows across 4 threads with 4 connections and the Bulk API drops from 492 ms to <strong>330 ms</strong>, the fastest Java-client result in the whole series.</p> <p>But parallelism isn't a free lunch — threads past 4 give diminishing returns, concurrent readers slow the writers 2.5x, and the TABLOCK hint changes the trade-off. Here's where the inflection points actually are.</p>