Storage & Databases

B-tree, hash, composite, covering indexes, write overhead, and when not to index

Memtable, SSTables, Bloom filters, compaction strategies, and B-tree vs LSM tradeoffs

Row vs columnar layout, compression, vectorized execution, Parquet, and OLAP vs OLTP

ACID, MVCC, WAL, buffer pool, and query planner

Decision framework, polyglot persistence, and NewSQL

Data structures, persistence, clustering, eviction, and use cases

Partition key, consistency levels, compaction, and hot partition avoidance

BSON, aggregation pipeline, replication, and sharding

Flat namespace, multipart upload, consistency model, and durability

Append-mostly writes, compression, retention, and downsampling