WAL

What is a Write-Ahead Log (WAL) and Why Do Databases Use One?

A write-ahead log (WAL) is a durability mechanism where the database records every change as a sequential log entry on stable storage before it modifies the ac…

How Does the Write-Ahead Log Enable Crash Recovery?

The write-ahead log enables crash recovery because, on restart, the database replays log records to redo committed changes that never made it to data pages, th…

What is Checkpointing in a Database and Why is it Needed?

Checkpointing is the process of periodically flushing all dirty (modified but unwritten) data pages from memory to disk and recording a marker in the write-ahe…

What is Transaction Log Shipping and How is it Used?

Transaction log shipping is a high-availability technique where the write-ahead or transaction log records generated on a primary database are continuously cop…