Re: In-place updates and serializable transactions - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: In-place updates and serializable transactions
Date
Msg-id CACjxUsOPzRZsomSUU9rfba_Cy3yqT1txwaE9oV4_ztxCavysSQ@mail.gmail.com
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In response to Re: In-place updates and serializable transactions  (Joshua Yanovski <joshua.yanovski@gmail.com>)
Responses Re: In-place updates and serializable transactions  (Kuntal Ghosh <kuntalghosh.2007@gmail.com>)
List pgsql-hackers
On Wed, Nov 14, 2018 at 5:43 AM Joshua Yanovski
<joshua.yanovski@gmail.com> wrote:

> This is only a personal anecdote, but from my own experience with serializability, this sort of blind update isn't
oftencontended in realistic workloads. 

> So, if this only affects transactions with blind updates, I doubt it will cause much pain in real workloads (even
thoughit might look bad in benchmarks which include a mix of blind writes and rmw operations).  Particularly if it only
happensif you explicitly opt into zheap storage. 

I agree with all of that, but will be very interested in what
failures, if any, kick out from the "isolation" test set when all
tables are created using zheap.  I added all the common failure
patterns I had seen to that set, and other have filled in some corner
cases I missed since then, so if everything there passes I would not
worry about it at all.  If we do see some failures, we can take
another look to see whether any action is needed.

--
Kevin Grittner
VMware vCenter Server
https://www.vmware.com/


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