Viewing profile — AlisdairO

Only on a per-connection basis

It supports transactional schema changes, but that's not what I'm talking about. Most schema changes require heavyweight locks on the tables they're altering. The locks might be sh…

Regarding schema changes and timeouts - while having timeouts in place is good advice, you can go further. While running the schema rollout, run a script alongside it that kills an…

Depending on exactly what you need, you can often fake this with a functional index on mod(queue_value_id, 5000). You then query for mod(queue_value_id,5000) between m and n. You c…

Me> different people will have different strengths of addiction You> It's profoundly obvious you're missing the point, and conflating somehow having a low degree of addiction to so…

> How have fat people gotten thinner without those meds up until now, then? Mostly, they haven't. You and I are outliers. The population-level data tells us that overweight people …

Respectfully, have you ever had anything in your life that you have struggled desperately with, and needed help? Anything at all that might give you a little empathy on the topic? …

I used to (and I didn't find much relief from eye drops). For the headaches, turned out they were migraines, which I was getting from screwing up my face because my eyes were uncom…

* In that link, V11 is not the version of Postgres, it's the version of the test. Scroll down to DB Version. * Lots of versions are tested, but 9.2.1 is the only version I see on t…

That link isn't particularly convincing. As far as I can see, the only Postgres test performed on the hardware that the top MariaDB entries had was on a positively ancient Postgres…

self-plug, but you could give https://pgexercises.com/ a try. No need to spin up your own DB etc.

Why shouldn't they want the easy way out? I was obese twenty years ago, and lost the weight via diet and exercise. Keeping that weight off is the single hardest thing I have ever d…

Indeed - People In The Know have some cocnerns with this approach: https://ardentperf.com/2021/07/26/postgresql-logical-replica... . At $work we did use this approach to upgrade a …

Do that in most relational dbs in the default isolation level (read committed), and concurrently executing transactions will still be able to delete users underneath you after the …

I think it because a significant fraction of my career has been spent fixing db-concurrency-related mistakes for people once they hit scale :-). I’m not talking about using cascade…

Can you give an example? I’m not aware of a mechanism like that that will protect you from concurrency artifacts reliably - certainly not a general one.

> so long as your code is correct This is a pretty tough definition of correct, though. Without foreign key constraints you'll have a really tough time dealing with concurrency art…

Table User: userid, etc Table Resources: resourceid, userid, etc If I want to restrict deletion of a user to only be possible after all the resources are deleted, I'm forced into u…

How does this stay correct in the presence of concurrent activity?

HA on rds uses synchronous replication - you won’t lose data on automated failover under any normal circumstances.

This is the c-store paper, which was evolved into Vertica: http://www.cs.umd.edu/~abadi/vldb.pdf . It's very readable, worth a look. edit: column stores existed before c-store, but…

Fair enough - I've seen it more commonly in smaller machines, but they're also more common in the fleets I've observed (and the ones that are more likely to run close to the edge m…

I think the key here is what you mean by using swap. Having a lot of data swapped out is not bad in and of itself - if the machine genuinely isn't using those pages much, then now …

> If you have a build farm / CI machines, don't use swap. With swap, if a user schedules too many compiles at once, machine will slow to a halt and become kinda-dead, not quite tri…

just a note that in newer versions of PG I believe partition changes no longer require an access exclusive lock on the parent table, which I'm looking forward to when we upgrade...…