On Mon, 21 Aug 2023 at 14:42, Edoardo Panfili <edoard...@gmail.com> wrote:
> > > > Il giorno 21 ago 2023, alle ore 20:13, Peter J. Holzer <hjp-pg...@hjp.at> > ha scritto: > > > > On 2023-08-21 17:27:20 +0200, Edoardo Panfili wrote: > >> The attended result was a sequence of ten equal values but this is the > actual result: > >> p: -1 > >> p: -1 > >> p: -1 > >> p: -1 > >> p: -1 > >> p: -1.0 > >> p: -1.0 > >> p: -1.0 > >> p: -1.0 > >> p: -1.0 > > [...] > >> 2023-08-21 11:51:50.633 CEST [1511] user@testdb LOG: execute > <unnamed>: SET extra_float_digits = 3 > >> 2023-08-21 11:51:50.634 CEST [1511] user@testdb LOG: execute > <unnamed>: SET application_name = 'PostgreSQL JDBC Driver' > >> 2023-08-21 11:51:50.644 CEST [1511] user@testdb LOG: execute > <unnamed>: SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.648 CEST [1511] user@testdb LOG: execute > <unnamed>: SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.649 CEST [1511] user@testdb LOG: execute > <unnamed>: SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.650 CEST [1511] user@testdb LOG: execute > <unnamed>: SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.651 CEST [1511] user@testdb LOG: execute S_1: > SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.651 CEST [1511] user@testdb LOG: execute S_1: > SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.653 CEST [1511] user@testdb LOG: execute S_1: > SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.653 CEST [1511] user@testdb LOG: execute S_1: > SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.654 CEST [1511] user@testdb LOG: execute S_1: > SELECT dim1 FROM number WHERE name='first' > >> 2023-08-21 11:51:50.656 CEST [1511] user@testdb LOG: execute S_1: > SELECT dim1 FROM number WHERE name=‘first' > > > > Are these outputs from the same run? > Yes > > > > > I notice that the output from the program switches after 5 queries from > > "-1" to "-1-0", but the logged query name switches after 4 queries from > > "<unnamed>" to "S_1”. > > You’re right. It seem a JDBC side problem. I am doing some tests using > suggestions from pgsql-jdbc list. > > What sounds strange to me is that switching from “mode_X” to “mode_Y” I > obtain different representation of the same value, > > I know the value is semantically the same.. but… in some way I like to > see.. "a perfect postgresql env” (as it absolutely is) > > Edoardo > > I have confirmed that this behaviour is by design either by postgres or the driver. When postgres provides us the data using text mode we see -1 (psql) select * from number ; name | dim1 -------+------ first | -1 This is the way the data is presented by the text output function. In binary mode we see -1.0. This is an artifact of the binary output function. If ResultSet.getDouble is used the data is the same ... -1 for both text and binary Using getString we see the problem. So you have a few options to stop this: Set prepareThreshold to 0 and the driver will not switch to named statements or binary, Or remove double from binary transfer. Regards, Dave
