On: What I wish someone told me about Postgres

[jedberg]

My number one tip: Vacuum every day!

I didn't know this when I started, so I never vacuumed the reddit databases. Then one day I was forced to, and it took reddit down for almost a day while I waited for it to finish.

[FreakLegion → jedberg]

No autovacuum? At reddit's scale I'm surprised you didn't run out of transaction IDs.

[jedberg → FreakLegion]

I turned it off because it would run at inopportune times.

And we did run out of transaction IDs, which is why I was forced to do it.

I never turned on the auto-vacuumer but I did set up a daily vacuum.

Keep in mind I left Reddit 13 years ago and I’m sure they’ve made improvements since.

[gtaylor → FreakLegion]

Auto vacuuming is enabled now. We did have some near misses due to long running vacuums that barely completed before wraparounds, but got things tuned over time.

I did none of that work but was on the team where it happened.