On 9/21/24 01:31, shihao zhong wrote:
Nisha Moond <nisha.moond...@gmail.com> writes:
Thoughts? Looking forward to hearing others' opinions!
Had a productive conversation with Amit Kaplia today about time skew
in distributed systems, and wanted to share some thoughts.
Essentially, we're grappling with the classic distributed snapshot
problem. In a multi-active environment, where multiple nodes can
independently process transactions, it becomes crucial to determine
the visibility of these transactions across the system. Time skew,
where different machines have different timestamps make it a hard
problem. How can we ensure consistent transaction ordering and
visibility when time itself is unreliable?
As you mentioned, there are several ways to tackle the time skew
problem in distributed systems. These approaches generally fall into
three main categories:
1. Centralized Timestamps (Timestamp Oracle)
2. Atomic Clocks (True Time)
3. Hybrid Logical Clocks
4 Local Clocks
I recommend ...<snip>... implement a pluggable time access method. This
allows users to integrate with different time services as needed.
Huge +1
In the mid-term, implementing the HLC approach would provide highly
consistent snapshot reads. This offers a significant advantage for
many use cases.
agreed
Long-term, we should consider integrating with a distributed time
service like AWS Time Sync Service. This ensures high accuracy and
scalability for demanding applications.
I think the pluggable access method should make this possible, no?
--
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
