Metabase can run on Heroku’s Free Tier, which only has 512MB, but it’s a highly optimized platform.
But it depends a lot on how many database source you have, how many people are using Metabase at the point when the Pulse task is being executed - and I would guess it also makes a difference which Java and version you’re using.
And if pulses are just a simple number/graph or if it includes an attachment.
Which version of Metabase are you using?
Could it be that each pulse task is not releasing it’s memory before going onto the next one?
There’s several issues involving memory issues, but none of them seems to fit your problem: