Comparison – Disk vs. MOT

The following table briefly compares the various features of the openGauss disk-based storage engine and the MOT storage engine.

Table 1 Comparison – Disk-based vs. MOT

Feature	openGauss Disk Store	openGauss MOT Engine
Intel x86 + Kunpeng ARM	Yes	Yes
SQL and Feature-set Coverage	100%	98%
Scale-up (Many-cores, NUMA)	Low Efficiency	High Efficiency
Throughput	High	Extremely High
Latency	Low	Extremely Low
Distributed (Cluster Mode)	Yes	Yes
Isolation Levels	RC+SI RR Serializable	RC RR RC+SI (in V2 release)
Concurrency Control	Pessimistic	Optimistic
Data Capacity (Data + Index)	Unlimited	Limited to DRAM
Native Compilation	No	Yes
Replication, Recovery	Yes	Yes
Replication Options	2 (sync, async)	3 (sync, async, group-commit)

Legend –

RR = Repeatable Reads
RC = Read Committed
SI = Snapshot Isolation

Appendices

References

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Glossary

Table 2 Glossary

Acronym	Definition/Description
2PL	2-Phase Locking
ACID	Atomicity, Consistency, Isolation, Durability
AP	Analytical Processing
ARM	Advanced RISC Machine, a hardware architecture alternative to x86
CC	Concurrency Control
CPU	Central Processing Unit
DB	Database
DBA	Database Administrator
DBMS	Database Management System
DDL	Data Definition Language. Database Schema management language
DML	Data Modification Language
ETL	Extract, Transform, Load or Encounter Time Locking
FDW	Foreign Data Wrapper
GC	Garbage Collector
HA	High Availability
HTAP	Hybrid Transactional-Analytical Processing
IoT	Internet of Things
IM	In-Memory
IMDB	In-Memory Database
IR	Intermediate Representation of a source code, used in compilation and optimization
JIT	Just In Time
JSON	JavaScript Object Notation
KV	Key Value
LLVM	Low-Level Virtual Machine, refers to a compilation code or queries to IR
M2M	Machine-to-Machine
ML	Machine Learning
MM	Main Memory
MO	Memory Optimized
MOT	Memory Optimized Tables storage engine (SE), pronounced as /em/ /oh/ /tee/
MVCC	Multi-Version Concurrency Control
NUMA	Non-Uniform Memory Access
OCC	Optimistic Concurrency Control
OLTP	Online Transaction Processing
PG	PostgreSQL
RAW	Reads-After-Writes
RC	Return Code
RTO	Recovery Time Objective
SE	Storage Engine
SQL	Structured Query Language
TCO	Total Cost of Ownership
TP	Transactional Processing
TPC-C	An On-Line Transaction Processing Benchmark
Tpm-C	Transactions-per-minute-C. A performance metric for TPC-C benchmark that counts new-order transactions.
TVM	Tiny Virtual Machine
TSO	Time Sharing Option
UDT	User-Defined Type
WAL	Write Ahead Log
XLOG	A PostgreSQL implementation of transaction logging (WAL - described above)