Re: [HACKERS] postgresql transactons not fully isolated

2017-06-21 Thread Merlin Moncure
On Tue, Jun 20, 2017 at 2:58 PM, Merlin Moncure wrote: > On Tue, Jun 20, 2017 at 2:34 PM, David G. Johnston > wrote: >> On Tue, Jun 20, 2017 at 12:22 PM, Chapman Flack >> wrote: >>> I get the reported result (DELETE 0 and a

Re: [HACKERS] postgresql transactons not fully isolated

2017-06-20 Thread J Chapman Flack
On 06/20/2017 12:33 PM, Merlin Moncure wrote: > postgres=# create table ints (n int); > CREATE TABLE > postgres=# insert into ints values (1); > INSERT 0 1 > postgres=# insert into ints values (2); > INSERT 0 1 > > T1: BEGIN > T1: UPDATE ints SET n = n + 1; > T2: BEGIN > T2: DELETE FROM ints

Re: [HACKERS] postgresql transactons not fully isolated

2017-06-20 Thread Merlin Moncure
On Tue, Jun 20, 2017 at 2:34 PM, David G. Johnston wrote: > On Tue, Jun 20, 2017 at 12:22 PM, Chapman Flack wrote: >> I get the reported result (DELETE 0 and a table containing 2 and 3) >> in both 'read committed' and 'read uncommitted'. > >

Re: [HACKERS] postgresql transactons not fully isolated

2017-06-20 Thread David G. Johnston
On Tue, Jun 20, 2017 at 12:22 PM, Chapman Flack wrote: > I get the reported result (DELETE 0 and a table containing 2 and 3) > in both 'read committed' and 'read uncommitted'. Practically speaking those are a single transaction isolation mode.

Re: [HACKERS] postgresql transactons not fully isolated

2017-06-20 Thread Chapman Flack
On 06/20/2017 03:08 PM, Chapman Flack wrote: > For me (in PG 9.5 at $work), at the instant of the commit in T1, > T2 says: > ERROR: could not serialize access due to concurrent update I get that result in 'serializable' and in 'repeatable read'. I get the reported result (DELETE 0 and a table

Re: [HACKERS] postgresql transactons not fully isolated

2017-06-20 Thread Tom Lane
Merlin Moncure writes: > Michael Malis via: > http://malisper.me/postgres-transactions-arent-fully-isolated/ has > determined that postgresql transactions are not fully isolated even > when using serializable isolationl level. > If I prep a table, ints via: > postgres=#

[HACKERS] postgresql transactons not fully isolated

2017-06-20 Thread Merlin Moncure
Michael Malis via: http://malisper.me/postgres-transactions-arent-fully-isolated/ has determined that postgresql transactions are not fully isolated even when using serializable isolationl level. If I prep a table, ints via: postgres=# create table ints (n int); CREATE TABLE postgres=# insert