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Fascinating disconnect I’ve seen on this one: - academic researchers: SERIALIZABLE isn’t the default? But everyone enables it first thing, right? - database users: SERIALIZABLE exists?

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"Why isolation level serializable is not the default?" reddit.com/r/Database/com Oh my.

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note: not exaggerating on this one. [postgresql.org, ~2011, around the time our work on Serializable Snapshot Isolation became available]

Survey Results
The current results of our Do you use SERIALIZABLE transaction mode? survey are:

Answer Responses Percentage

Yes, we depend on it for production code 29 15.026%
Yes, but only for a few non-critical things 11 5.699%
I've been messing with it in development (only) 17 8.808%
No, I never considered it 39 20.207%
No, I found SERIALIZABLE too unintuitive/undependable 10 5.181%
What's SERIALIZABLE? 81 41.969%

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Peter Geoghegan

@petervgeoghegan

Replying to

Even this seems biased - it's got to be more than 41%. (Please don't interpret this as a slight against SSI. SSI is a very important feature IMV.)

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Andres Freund (Tech)

@AndresFreundTec

Replying to

@petervgeoghegan

and

I wish somebody would spend a while making postgres' SSI implementation more scalable. Right now the locking is, uh, coarse grained. I don't think it'd even be that hard to do substantially better than we do right now.

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Peter Geoghegan

@petervgeoghegan

Replying to

@AndresFreundTec

and

That's almost certainly true, but I maintain that the main problem by far is the developer experience. And I don't know what can be done about that.

8:00 PM · Sep 15, 2022Twitter Web App

Replying to

@petervgeoghegan

@AndresFreundTec

and

What do you mean by “the developer experience”?

Replying to

@petervgeoghegan

@AndresFreundTec

and

My answer: fix the remaining obstacles to auto-retry, and encourage users to use decent transaction management libraries that do that.

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Peter Geoghegan

@petervgeoghegan

Replying to

@AndresFreundTec

and

Hmm. Maybe having good/better framework-level support would actually move the needle. It at least addresses the root problem, which is a start.

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Replying to

@petervgeoghegan

@AndresFreundTec

and

The coarse-grained locks are part of the developer experience, especially when they cause a sudden outage