Re: Serializable Isolation and read/write conflict with index and different keys

I have inserted a row that i don't touch, runned ANALYZE and tried again
but with the same result.
I'm using postgres 9.6.3 and EXPLAIN ANALYZE shows this:

Index Scan using users_username_idx on users (cost=0.13..8.14 rows=1
width=4) (actual time=0.020..0.020 rows=0 loops=1)

Index Cond: (name = 'bob'::text)

2017-08-30 0:13 GMT+02:00 Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>:

> On Wed, Aug 30, 2017 at 4:28 AM, Luca Looz <luca(dot)looz92(at)gmail(dot)com> wrote:
> > I'm trying to use the serializable isolation but i'm getting read/write
> > dependencies error even if i have an unique index on the column used and
> the
> > transactions are using different keys.
> > For an example see this gist:
> > https://gist.github.com/nathanl/f98450014f62dcaf0405394a0955e18e
> > Is this an expected behavior?
>
> Take a look at the EXPLAIN plan for the SELECT. You'll get fine
> grained SIREAD locks if it's doing a btree index scan, but table-level
> SIREAD locks for other kinds of plans. Sometimes simple SSI tests can
> show a lot of false positives just because of empty tables or missing
> statistics (ANALYZE).
>
> --
> Thomas Munro
> http://www.enterprisedb.com
>