Top 3 C++ oltp Projects

stonedb

7 851 7.2 C++

StoneDB is an Open-Source MySQL HTAP and MySQL-Native DataBase for OLTP, Real-Time Analytics, a counterpart of MySQLHeatWave. (https://stonedb.io)
corobase

1 228 0.0 C++

Coroutine-Oriented Main-Memory Database Engine (VLDB 2021)
InfluxDB

www.influxdata.com featured

Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
ScaleStore

2 108 3.4 C++

This is the source code for our (Tobias Ziegler, Carsten Binnig and Viktor Leis) published paper at SIGMOD’22: ScaleStore: A Fast and Cost-Efficient Storage Engine using DRAM, NVMe, and RDMA.

Project mention: Ask HN: Why are there no open source NVMe-native key value stores in 2023? | news.ycombinator.com | 2023-10-16

I don't remember exactly why I have any of them saved, but these are some experimental data stores that seems to be fitting what you're looking for somewhat:
- https://github.com/DataManagementLab/ScaleStore - "A Fast and Cost-Efficient Storage Engine using DRAM, NVMe, and RDMA"
- https://github.com/unum-cloud/udisk - "The fastest ACID-transactional persisted Key-Value store designed for NVMe block-devices with GPU-acceleration and SPDK to bypass the Linux kernel."
- https://github.com/capsuleman/ssd-nvme-database - "Columnar database on SSD NVMe"

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).