Re: Predicate locking

Kevin Grittner wrote:
>> I don't think Vlad is being unreasonable here; he's provided a
>> test case demonstrating the behavior he'd like to see, and shown
>> it doesn't work as expected.
>>     
>  
> ... on a toy table with contrived values.  How different is this
> from the often-asked question about why a query against a four-line
> table is not using the index they expect, and how can we expect it
> to scale if it doesn't?

It's not, but in that case I've been known to show someone that the 
behavior they're seeing doesn't happen on a larger table.  My point was 
just that no one has really done that here yet:  provided an example 
showing SSI serialization working as a substitute for predicate locking 
in this sort of use case.  I trust that the theory is sound here, and 
yet I'd still like to see that demonstrated.  This is why I launched 
into making a less trivial test case.

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us