databases
12 articles tagged databases.
-
Database Write-Ahead Logs and Crash Recovery
How write-ahead logging protects database updates and lets recovery replay committed work after a crash without leaving inconsistent pages.
-
MVCC Snapshots and Row Version Visibility
How MVCC snapshots choose visible row versions so SQL readers and writers can run concurrently without blocking each other.
-
SQL Query Cardinality Estimation and Histograms
How SQL planners use table statistics to estimate predicate results and choose scans, joins, and execution strategies.
-
Skip Lists and Expected Logarithmic Index Operations
Layered linked lists let skip lists search, insert, and delete ordered data in expected logarithmic time through randomized node heights.
-
SQL Write-Ahead Logs and Crash Recovery
A write-ahead log records transaction changes durably before data pages, allowing a SQL database to recover committed work after a crash.
-
Quorum Reads and Writes in Replicated Datastores
How N, R, and W thresholds trade consistency for availability when replicated datastore nodes fail or lag.
-
MVCC Snapshots and SQL Row Visibility
How SQL transactions choose visible row versions so readers can use a consistent view while writers update the same data.
-
SQL NULL and Three-Valued Logic
Understand SQL NULL, UNKNOWN predicate results, and why WHERE, JOIN, and CHECK constraints handle them differently.
-
DynamoDB Adaptive Capacity and Hot Partition Keys
DynamoDB adaptive capacity shifts unused throughput toward hot partition keys while keeping the table’s provisioned capacity unchanged.
-
SQL Selectivity Estimates and Query Plans
How database planners use histograms to estimate matching rows, and how bad estimates lead to unexpectedly slow scans, joins, and indexes.
-
Database B-Tree Page Splits and Separator Keys
How B-tree pages split at capacity, propagate separator keys, and preserve fast, logarithmic index lookups.
-
Database Write-Ahead Logging and Crash Recovery
How databases use durable log records to preserve committed transactions and remove incomplete changes after a crash.