Hello,
I hope you are doing well.
In PostgreSQL 16, startup appears to initialize databases sequentially and
primarily uses a single CPU core. In clusters with a very large number of
databases (around 5,000 in our case), this results in noticeably long
startup times after restarts or crash recovery.
I would like to ask:
- Is the largely single-threaded startup behavior a fundamental architectural
constraint (e.g. catalog dependencies, locking, recovery ordering), or mainly
an unimplemented optimization?
- Are there any existing discussions, patches, versions (18+) to parallelize parts of startup or otherwise improve startup scalability with many databases?
- Are there any PostgreSQL configuration settings known to dramatically reduce startup time, or is startup performance mostly fixed by architecture in this scenario?
I understand that having many databases in a single cluster is not the most
common or recommended multi-tenant model, but this is an existing system and
I’m trying to better understand the current limits and future direction.
Thank you for your time and insights.
Best regards.
