8 min read
PostgreSQL synchronous_commit: A Durability Dial, Not a Switch
synchronous_commit is the rare setting that trades durability for latency openly. Used per transaction, it is the fastest safe win on a write-heavy pipeline.
Database Field Notes
Notes for the problems that show up after launch: bad plans, awkward migrations, index debt, vacuum pressure, replica lag, and the small decisions that keep PostgreSQL, MySQL, MariaDB, and SQL Server easier to operate.
Featured Guides
Slow query optimization
Find the queries dragging your Postgres down, read their plans, and fix them in order of impact.
Read the guide →Index optimization
Which indexes to add, which to drop, and how to spot redundant index debt before it costs you writes.
Read the guide →Vacuum guide
How autovacuum works, when it falls behind, and how to keep bloat from eating your storage and your buffer cache.
Read the guide →Connection pooling
Sizing pools, PgBouncer modes, and how to stop idle-in-transaction sessions from exhausting max_connections.
Read the guide →Replication monitoring
Track lag, WAL throughput, and replication slots before they turn into stale reads or a full disk.
Read the guide →Browse by Topic
Backups and Durability
9 articlesBackups, restores, PITR, archive gaps, and recovery drills for PostgreSQL.
Cloud Providers
5 articlesAWS RDS, Azure Database for PostgreSQL, Google Cloud SQL, AlloyDB, and managed PostgreSQL monitoring notes.
Connections and Pooling
10 articlesConnection storms, pool saturation, PgBouncer behavior, and max_connections pressure.
CPU, Memory, and I/O
17 articlesCPU, memory, disk, temp files, checkpoints, buffers, and workload pressure.
Indexes
37 articlesIndex design, index debt, reindexing, constraint indexes, and evidence-driven DDL.
Locks and Transactions
22 articlesLock waits, deadlocks, blocking chains, idle transactions, and transaction hygiene.
MariaDB
56 articlesGalera clustering, InnoDB and Aria internals, replication, optimizer behavior, and MariaDB operations notes.
MySQL
107 articlesInnoDB internals, replication, locking, query performance, and MySQL operations notes.
pgvector and RAG
15 articlesHNSW, IVFFlat, recall, embedding search, and production RAG performance notes.
Replication and WAL
28 articlesReplica lag, WAL growth, failover readiness, hot standby behavior, and replication slots.
Slow Queries
38 articlesQuery plans, EXPLAIN ANALYZE, planner regressions, pagination, joins, and statistics.
SQL Server
47 articlesWait statistics, tempdb, Query Store, Always On availability groups, and SQL Server operations notes.
Vacuum and Bloat
16 articlesAutovacuum, dead tuples, bloat, wraparound, MVCC, freeze age, and visibility.
Latest Field Notes
8 min read
PostgreSQL Huge Pages: TLB Pressure and Large shared_buffers
The bigger the shared_buffers and the more connections mapping them, the more 4KB pages cost you in TLB misses and page-table memory. Huge pages are cheap to set up if you size them honestly.
7 min read
MaxScale Read/Write Splitting for MariaDB: A Field Guide
MaxScale's readwritesplit router gives your application one endpoint and spreads reads across replicas. Here is how routing decisions are made, where session state bites, and how failover coordination works.
8 min read
READ_COMMITTED_SNAPSHOT: Turn It On, but Know What Changes
One database setting ended our reader-writer blocking overnight and introduced two bugs we only caught in a concurrency soak. RCSI mechanics, the honest migration checklist, and the version-store monitoring that keeps tempdb safe.
8 min read
How to Read a SQL Server Deadlock Graph Without Guesswork
A week of error 1205s and a proposed retry loop that would fix nothing. How to pull deadlock graphs from system_health, read victim, owner, and waiter nodes, and kill the three patterns behind most deadlocks.
7 min read
SQL Server Query Store: Hunting Regressions After a Deploy
The deploy that doubled p95 left its fingerprints in sys.query_store_runtime_stats. How to configure Query Store so the data is there when you need it, compare intervals to find the regressed plan, and force a plan without fooling yourself.
8 min read
SQL Server Index Maintenance: The Nightly Rebuild Reality Check
The nightly REBUILD job I inherited burned 90 GB of transaction log and fixed nothing. What fragmentation still means on flash, what REBUILD actually buys over REORGANIZE, and why updating statistics is usually the real win.
9 min read
SQL Server Wait Statistics Triage with sys.dm_os_wait_stats
Since-restart wait totals average your quietest night and your worst deploy into one meaningless number. Here is how I diff sys.dm_os_wait_stats over an interval, drop the benign noise list, and branch on what CXPACKET, PAGEIOLATCH, WRITELOG, and LCK_M_* are actually…
9 min read
SQL Server tempdb Contention: Fixes That Actually Work
A batch job that got slower as we added workers was queueing on three pages in tempdb. How to tell PAGELATCH from PAGEIOLATCH, size the data files, weigh memory-optimized metadata in 2019, and keep the version store from eating the…
8 min read
PostgreSQL JIT Compilation: When the Planner Makes Queries Slower
JIT compilation is supposed to make big PostgreSQL queries faster, but bad cost estimates fire it up on cheap ones. Here is how to spot the regression and switch it off safely.