Live data from Hacker News

Ask HN: How do you update multiple disparate databases?

news.ycombinator.com

51–55 of 55 posts

Re: Ask HN: How do you update multiple disparate databases?

#51

It would be hard to formulate a one-size-fits-all solution even if you were talking about relatively modern systems. There’s a trade-off between having a manual vs. automated process in the best of circumstances. You might think intuitively that an automated process would be easier and more reliable, but depending on local factors for each of the databases, there might be issues like availability or locking that coul…

This is such a good answer because sometimes a system where people are used to solve the issue is the right way.

And I say 'system' because as long as the company knows that Sally does the updating each day, but if Sally is on holidays or sick or quits, then there is a protocol where the work is done and the checks/balances are done to ensure that that mortgage rate change is done.

Re: Ask HN: How do you update multiple disparate databases?

#52

Step 1) Generate a GUID Step 2) Send a message to all the `downstream` systems (i.e. not the Source of Truth systems) with the change description and GUID Step 3a) Update source of truth with the new info, write the GUID to a log table in source of truth in the same transaction Step 3b,c,d) Downstream systems poll the source of truth for existence of the GUID in the log table indicating the change has been committed…

Is this a known pattern in distributed systems?

It's basically a generational cache pattern
Post reply on HN