--- title: Linux 7.2 boosts MongoDB throughput 100%, Datadog... description: A curated roundup of database and systems engineering news. Linux 7.2's MGLRU improvements deliver up to 100% MongoDB throughput gains on slower I/O and 30% on... canonical: https://daily.dev/posts/linux-7-2-boosts-mongodb-throughput-100-datadog-rewrites-routing-from-foundationdb-to-postgres-hwwlgqhc5 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Linux 7.2 boosts MongoDB throughput 100%, Datadog rewrites routing from FoundationDB to Postgres | daily.dev og:description: A curated roundup of database and systems engineering news. Linux 7.2's MGLRU improvements deliver up to 100% MongoDB throughput gains on slower I/O and 30% on... og:url: https://daily.dev/posts/linux-7-2-boosts-mongodb-throughput-100-datadog-rewrites-routing-from-foundationdb-to-postgres-hwwlgqhc5 og:image: https://api.daily.dev/og/posts/hwWLgqHC5.png og:image:alt: Linux 7.2 boosts MongoDB throughput 100%, Datadog rewrites routing from FoundationDB to Postgres og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Linux 7.2 boosts MongoDB throughput 100%, Datadog rewrites routing from FoundationDB to Postgres **[Databases Digest](https://daily.dev/sources/databases_digest)** · 4 min read · 0 upvotes · 0 comments ## Summary A curated roundup of database and systems engineering news. Linux 7.2's MGLRU improvements deliver up to 100% MongoDB throughput gains on slower I/O and 30% on NVMe. Datadog migrated their Stream Router from FoundationDB to PostgreSQL/DuckDB under live traffic, cutting a 45-minute operation to ~1 second and reducing database costs by 90%, with honest observations about AI-generated SQL requiring human optimization. Debezium 3.6.0.CR1 introduces off-heap RocksDB storage for table history, cutting MySQL connector memory usage by 75%. DuckCon #7 previewed DuckDB 2.0 with VARIANT type, triggers, and async object store I/O. Also covered: Visa's ClickHouse materialized views delivering 30-70x query speedups, PostgreSQL checkpoint stall incidents causing multi-hour outages, new PostgreSQL 17/18 planner GUCs, Quarkus 3.37 with Hibernate ORM 7.4, and a MySQL-to-PostgreSQL CDC migration guide. ## Content **TLDR:** Linux 7.2's MGLRU improvements are showing real numbers: up to 100% throughput gains for MongoDB on slower I/O, 30% on NVMe. Datadog migrated their Stream Router from FoundationDB to PostgreSQL/DuckDB while serving live traffic, cutting a 45-minute operation to ~1 second and dropping database costs 90%. Debezium 3.6.0.CR1 landed with off-heap RocksDB storage for table history and a 75% memory reduction in the MySQL connector. DuckCon #7 previewed DuckDB 2.0 with VARIANT type, triggers, and async I/O for object stores. --- ## Linux 7.2 MGLRU improvements: up to 100% MongoDB throughput gain The Linux 7.2 MM subsystem changes are now merged, and the headline number is hard to ignore: up to 100% throughput improvement for MongoDB on slower I/O, 30% on NVMe, driven by fixes to MGLRU's reclaim loop and dirty writeback handling. Other changes include faster batch freeing of order-0 pages (addressing vmalloc regressions) and tightened mmap_miss accounting that reduces synchronous readahead for sparse random and strided access patterns. If you're running MongoDB on anything slower than NVMe, this is worth tracking when 7.2 hits your distro. [Read more](https://daily.dev/posts/SwHdndsKo) ## Datadog migrates Stream Router from FoundationDB to PostgreSQL/DuckDB: 45 minutes to ~1 second Datadog's team moved their Stream Router from a key-value FoundationDB model to a relational PostgreSQL/DuckDB architecture under live production traffic, using Claude and Cursor in a test-driven loop. The results are striking: a 45-minute operation now runs in roughly 1 second, the routing dataset shrank 40x, and database costs fell 90%. The honest part of the writeup is worth reading: AI consistently produced correct but unoptimized SQL, requiring human intervention for batching, UNNEST tricks, and CTEs. Their conclusion — the quality of your test suite is the ceiling for how much you can trust AI-generated code — is the right frame for anyone considering this approach. [Read more](https://daily.dev/posts/1LSw1ClgT) ## Debezium 3.6.0.CR1: off-heap RocksDB history, 75% MySQL connector memory reduction Debezium 3.6.0.CR1 introduces off-heap memory management for table history and schemas using RocksDB, which matters for connectors tracking large schemas over long periods. The MySQL connector's poll path sees a 75% reduction in memory allocation and 31-42% CPU overhead reduction. Oracle connector improvements include exponential back-off for XStream attach retries, deferred transaction creation until first DML, and better diagnostics for missing archive logs. The release resolves 44 issues total, including a KafkaSchemaHistory recovery race condition and PostgreSQL varbit column handling. [Read more](https://daily.dev/posts/eiXmjK3Z6) ## DuckCon #7: DuckDB 2.0 previews VARIANT type, triggers, and async object store I/O DuckCon #7 in Amsterdam surfaced the DuckDB 2.0 roadmap: VARIANT type for semi-structured data, triggers, async I/O for object stores, and a more stable C API. Talks covered SQLFrame for migrating PySpark workloads to DuckDB, Spotify's adoption, MariaDB using DuckDB as a storage engine, and DuckLake with semantic search. The pg_lake talk on Postgres-Iceberg integration and DuckLake running on Hetzner for under €15/month are worth digging into if you're watching the local analytics space. [Read more](https://daily.dev/posts/RHmxGDCU0) --- ## Also notable - **Visa: ClickHouse materialized views cut 500K-row query from 2-3 seconds to 100ms:** Visa's Authorize.net team replaced multi-day BI reporting with conversational analytics on 40 PBs of payments data using ClickHouse Cloud and LibreChat; materialized views deliver 30-70x query speedups, with a 500K-row revenue analysis dropping from 2-3 seconds to 100ms via a 624-row pre-computed view. [Read more](https://daily.dev/posts/F2l99B9zJ) - **PostgreSQL checkpoint stalls: 40-hour outage from inode exhaustion, 8.5-hour standby loop on Kubernetes:** Two production incidents make the case for alarming on checkpoint duration: one caused a 40-hour outage from 27 million unlinked files and inode exhaustion after a week-long checkpoint stall, another caused an 8.5-hour standby loop in CloudNativePG due to disk I/O saturation and a 60-minute startup probe timeout. [Read more](https://daily.dev/posts/8r64jnswX) - **PostgreSQL 17/18 GUCs: enable_group_by_reordering and enable_distinct_reordering:** PostgreSQL 17 and 18 added enable_group_by_reordering and enable_distinct_reordering, planner GUCs that permute GROUP BY and DISTINCT keys to minimize comparison costs and avoid redundant sorts — if a query regressed after upgrading, check the plan for reordered keys and run ANALYZE before reaching for the GUC disable. [Read more](https://daily.dev/posts/XhdvYn0Ky) - **Quarkus 3.37: Hibernate ORM 7.4 with PostgreSQL 14 minimum and SQL-level pagination changes:** Quarkus 3.37 bumps Hibernate ORM to 7.4, which brings behavioral changes including SQL-level pagination limits, new NOT NULL constraints on timestamp columns, and a PostgreSQL 14 minimum — worth reviewing before upgrading if you're on older Postgres or rely on Hibernate's pagination behavior. [Read more](https://daily.dev/posts/AxuVjuezI) - **MySQL to PostgreSQL migration: CDC-based low-downtime cutover with tool comparison:** A practical walkthrough covers the full MySQL-to-PostgreSQL migration path including data type mapping, SQL dialect rewrites, stored procedure porting to PL/pgSQL, and a comparison of DBConvert, pgloader, and AWS DMS for low-downtime CDC-based cutover. [Read more](https://daily.dev/posts/dmxVYvju7) --- Tags: [#linux](https://daily.dev/tags/linux), [#backend](https://daily.dev/tags/backend), [#postgresql](https://daily.dev/tags/postgresql), [#duckdb](https://daily.dev/tags/duckdb), [#debezium](https://daily.dev/tags/debezium) [View this post on daily.dev](https://daily.dev/posts/linux-7-2-boosts-mongodb-throughput-100-datadog-rewrites-routing-from-foundationdb-to-postgres-hwwlgqhc5) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"DiscussionForumPosting","mainEntityOfPage":"https://daily.dev/posts/linux-7-2-boosts-mongodb-throughput-100-datadog-rewrites-routing-from-foundationdb-to-postgres-hwwlgqhc5","headline":"Linux 7.2 boosts MongoDB throughput 100%, Datadog rewrites routing from FoundationDB to Postgres","text":"A curated roundup of database and systems engineering news. 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