Presented by:

Sangwook kim

Sangwook Kim


Sangwook (Shawn) Kim is a co-founder and CEO at Apposha, which is building PostgreSQL extension for scalable file I/O. Before founding Apposha, Sangwook worked at Computer Systems Laboratory in Sunkyunkwan University. His main work was developing operating system-level techniques for database performance. Specifically, Sangwook has over 9 years experience in analyzing and optimizing Linux kernel for open source databases including PostgreSQL, MongoDB, MySQL, and Redis.

He spoke at various PostgreSQL Conferences in the past including -

PGDay Seoul - 2017

PGConf Asia - 2017

PGDay Seoul - 2018

PGConf Asia - 2019

Postgres Conference Silicon Valley - 2019

PGDay Seoul - 2019

PGConf Russia - 2020


Byeonghun Hyeon

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Cloud storage has some unique characteristics compared to traditional storage mainly because it is virtualized and controlled by software. One example is that AWS EBS shows higher throughput with larger I/O size up to 256 KiB without hurting latency. Hence, a user can get only about 4 MiB/sec with 1,000 IOPS EBS volume if the I/O request size is 4 KiB, whereas a user can get about 250 MiB/sec if the I/O request size is 256 KiB. This is because EBS consumes one I/O in a given IOPS budget for every I/O request regardless of the I/O size (up to 256 KiB). Unfortunately, PostgreSQL cannot exploit the full potential of cloud storage because PostgreSQL has designed without considering the unique characteristics of cloud storage.

In this talk, I will introduce the AppOS extension that improves the throughput of a write-intensive workload by 10x by transparently making PostgreSQL cloud storage-native. AppOS works like a storage driver that efficiently exploits the characteristics of cloud storage, such as I/O size dependency to storage throughput and latency, atomic write support in cloud block storage, and fast, but non-durable local SSDs. To do this, AppOS comprises a Linux-compatible file I/O stack including virtual file system, page cache, block I/O layer, cloud storage driver. On top of the file I/O stack, syscall module supports registering pre- and post-handler for file I/O-related system calls in order to transparently work without modifying PostgreSQL codes.

I will focus on presenting key use cases and performance results of the AppOS extension after explaining the internals. Specifically, I will show the performance results of OLTP and some batch workloads using standard benchmarking tools like pgbench and sysbench. I will also present performance results and implications on multiple clouds including AWS, GCP, and Azure. Lastly, I will show the extensibility of the AppOS extension by showing several results with TimescaleDB, CitusDB, and MariaDB as well as PostgreSQL.

50 min
Postgres Conference 2020
Ops and Administration