ClickHouse Buffers Every Byte: One Cursor, One nextImpl() Refill, and a memcpy Fast Path
ClickHouse replaces iostreams with ReadBuffer/WriteBuffer: one cursor, one virtual refill, and a memcpy fast path.
Clickhouse
ClickHouse's CODEC(...) Is a Pipeline, Not an Algorithm: Delta, Gorilla and One Method Byte
ClickHouse’s column codecs are bit-level transforms chained under a generic compressor: Delta, DoubleDelta and Gorilla, nested by CODEC(…).
ClickHouse's Hashed Dictionary Packs a Composite Key Into One Arena Blob: 128 Shards, 128 Threads
The hashed dictionary packs keys compactly, shards the table for parallel loading, and picks its hash table by measured memory footprint.
ClickHouse Turns a Distributed INSERT into .bin Files on Disk: The Filesystem Is the Queue
ClickHouse turns a Distributed INSERT into files on disk and ships them in the background.
ClickHouse's Query Condition Cache: Only Empty Granules, Never a Full Match
ClickHouse caches the granules a predicate emptied, so a dashboard that runs the same query every 30 seconds stops paying for index analysis and skipped data.