Glossary

Terms

These short definitions can help you build the right mental model when reading the rest of the docs.

Term	Definition
A
AST	Abstract Syntax Tree — the tree representation of code, a fundamental piece of a compiler.
C
Cluster	The distributed deployment form of MatrixOne, made up of multiple hosts that act as a single logical system.
E
Explicit Transaction	A transaction in which you explicitly decide which set of operations must succeed or fail together, controlled with BEGIN TRANSACTION and ROLLBACK TRANSACTION / COMMIT TRANSACTION.
I
Implicit Transaction	An auto-commit transaction.
O
Optimistic Transaction	A transaction that does no conflict detection or locking when it starts; it caches the relevant data in memory and applies inserts / updates / deletes against it.
P
Pessimistic Transaction	The default transaction model in MatrixOne. When the transaction starts, it assumes write contention is possible and locks the relevant tables or rows in advance; insert / update / delete are buffered in memory and persisted only on commit (or discarded on rollback), with the locks released.
S
Snapshot Isolation (SI)	A widely used multi-version concurrency control technique. MatrixOne supports distributed transactions at Snapshot Isolation.

Key concepts

Concept	Definition
A
Auto-Rebalance	In a distributed system, the automatic process of rebalancing storage and read/write load across multiple servers.
C
Consistency	MatrixOne provides strong consistency, guaranteeing that once a write succeeds, the latest data is visible from every Store (node).
E
Execution Plan	A graph representation of query operations produced by the query optimizer, describing the most efficient way to execute the query.
F
Fault-Tolerance	The ability of the system to keep running after one or more components fail.
M
Monolithic Engine	A hyper-converged engine that supports mixed workloads — TP, AP, time-series, machine learning.
Materialized View	A pre-computed dataset, persisted for later reuse, typically used to speed up queries.
Metadata	Data describing the structural information of data in a database.
P
Paxos	A consensus algorithm that keeps a group of distributed computers communicating asynchronously in agreement.
R
Raft	A consensus algorithm easier to understand than Paxos, comparable in fault tolerance and performance.
Raft Group and Leader	Raft defines a leader and several followers in a group. The group represents a replicated state machine; only the leader handles client requests, then propagates them to followers.
S
SIMD instruction	Single Instruction / Multiple Data — a way to process multiple pieces of data with one instruction.
T
Transaction	A series of operations against the database that satisfies the basic ACID requirements.
TAE	Transactional Analytic Engine — the storage engine. The storage engine is the main interface of the storage layer; TAE supports both row and columnar storage and transactional processing.
V
Vectorized Execution	By making efficient use of CPU caches, vectorized execution speeds up analytical query engines. Arrow’s columnar format enables lightweight techniques such as dictionary encoding, bit packing, and run-length encoding, all of which further improve query efficiency.