Senior DBA & SRE Engineering Glossary
MVCC, LSN, Split-Brain, WAL vs Redo, Spread Checkpoint, and Autovacuum: Core database internals explained with diagnostic queries.
Multi-Version Concurrency Control (Çoklu Sürüm Eşzamanlılık Denetimi)
A concurrency model where readers do not block writers, and writers do not block readers, providing consistent point-in-time snapshots.
Log Sequence Number (Günlük Sıra Numarası)
A monotonically increasing 64-bit integer representing the exact byte offset in the transaction write-ahead log stream.
Bölünmüş Beyin Sendromu (Dağıtık Küme İki Başlılık Krizi)
A critical distributed failure where network partitioning causes two independent nodes to both believe they are the write-master, causing irreversible data fork.
Write-Ahead Logging / Redo Log (Önceden Yazılan Günlük)
The fundamental storage principle enforcing ACID durability: Changes must be fsynced to a sequential append-only log before buffer pages are written to data files.
Denetim Noktası & Bellek-Disk Senkronizasyon Olayı
A known consistent state where all dirty memory buffers are flushed to disk, allowing older transaction logs to be recycled.
Autovacuum & Alan Geri Kazanım Mekanizması
The PostgreSQL background reclamation process that marks dead tuple space as reusable and freezes transaction IDs to prevent catastrophic XID wraparound.