Re: Serializable read only deferrable- implications

On 3/8/22 08:21, Tom Lane wrote:
> Michael Lewis <mlewis@entrata.com> writes:
>>> A transaction started with the first statement will not take any SI locks,
>>> nor will it ever receive a serialization error.
> 
>> What is the meaning of SI? Anything you are aware of in source code or a
>> blog post that discusses this?
> 
> There's src/backend/storage/lmgr/README-SSI, which might or might
> not be the level of detail you are looking for.

If you want to ease into the above:

https://www.postgresql.org/docs/current/mvcc-intro.html

"PostgreSQL maintains this guarantee even when providing the strictest 
level of transaction isolation through the use of an innovative 
Serializable Snapshot Isolation (SSI) level."

Then:

https://www.postgresql.org/docs/current/transaction-iso.html#XACT-SERIALIZABLE

and

https://www.postgresql.org/docs/current/applevel-consistency.html#SERIALIZABLE-CONSISTENCY

> 
>             regards, tom lane
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com