[Qgis-user] Problens in atribute tables (bug?)

[Jorge Gustavo Rocha]

Hi Frederico,

It would be very useful if you can isolate the problem.

You can enable logging for all Postgresql queries. Edit you
postgresql.conf file and change log_statement = 'all'. Restart
Postgresql. Open the log to see what is going on.

Duplicate you table on another schema or database and play with it.

I've created a new table, with an additional x and y columns for the
labels and I did some editing. I've set the label positioning to x and y.

CREATE TABLE public.cemiterio (
	fid serial NOT NULL,
	nome varchar(100) NULL,
	x numeric(10) NULL,
	y numeric(10) NULL,
	wkb_geometry geometry(Point, 3857),
	CONSTRAINT cemiterio_pkey PRIMARY KEY (fid)
);

Everything went fine. When changing the directly the attribute table, I
get just one single update. For example:

2018-11-17 23:13:15.263 WET [29639] geobox at geotuga LOG:  statement: BEGIN
2018-11-17 23:13:15.263 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "x"=-1923181 WHERE "fid"=3
2018-11-17 23:13:15.263 WET [29639] geobox at geotuga LOG:  statement: COMMIT
2018-11-17 23:13:15.275 WET [29537] geobox at geotuga LOG:  statement:
BEGIN READ ONLY
2018-11-17 23:13:15.275 WET [29537] geobox at geotuga LOG:  statement:
DECLARE qgis_38 BINARY CURSOR FOR SELECT
st_asbinary("wkb_geometry",'NDR'),"fid","nome"::text,"x"::text,"y"::text
FROM "public"."cemiterio" WHERE "wkb_geometry" &&
st_makeenvelope(-1921084.8524324435275048,3785638.23111640242859721,-1736633.8711264121811837,3881349.90870131878182292,3857)
2018-11-17 23:13:15.276 WET [29537] geobox at geotuga LOG:  statement:
FETCH FORWARD 2000 FROM qgis_38
2018-11-17 23:13:15.276 WET [29537] geobox at geotuga LOG:  statement:
CLOSE qgis_38
2018-11-17 23:13:15.276 WET [29537] geobox at geotuga LOG:  statement: COMMIT

When updating using the field calculator, I get all the updates:

2018-11-17 23:12:30.085 WET [29639] geobox at geotuga LOG:  statement: BEGIN
2018-11-17 23:12:30.086 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "y"=3900084.04311737 WHERE "fid"=1
2018-11-17 23:12:30.086 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "y"=3875154.0323308 WHERE "fid"=2
2018-11-17 23:12:30.087 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "y"=3850565.52854132 WHERE "fid"=3
2018-11-17 23:12:30.088 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "y"=3852551.36467331 WHERE "fid"=4
2018-11-17 23:12:30.088 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "y"=3832291.8228186 WHERE "fid"=5
2018-11-17 23:12:30.089 WET [29639] geobox at geotuga LOG:  statement:
UPDATE "public"."cemiterio" SET "y"=3819588.03812478 WHERE "fid"=6
2018-11-17 23:12:30.089 WET [29639] geobox at geotuga LOG:  statement: COMMIT

I've use expressions to update x and y columns, like:
"x" + 100
or
$x - 50

You hit some issue probably, but it would be great if you could identify it.

I did the tests with QGIS 2.18.17 against Postgresql 10.

If you need further help, just ask.

Regards,

Jorge

> POSTGIS.  A  few days ago our team observed some strange problens
> updating data in atribute tables.
> 
> It is hard to explains, because we couldn't isolate the process and the
> error until now.
> 
> Basicly, wen we are updating data, using field calculator, manualy at
> the tables or using label placement by X and Y registred in table, QGIS
> send an update to the POSTGRES with a random value in a random column. 
> 
> We discovered the error when an 'F' was updated in a Integer column,
> when the user tried to save the edition, QGIS has returned a mensage
> with the error and, since that day, we are very apreensive because we
> dont know the damage in our database.
> 
> Since this is random, I did'nt try to send a bug report and haven't
> found a ticket that describe something like that.
> 
> Its is a very atipical situation. We use QGIS since 1.8(Lisboa) and this
> has never hapened with us.
> 
> We are using 2.18.12 with POSTGRES 9.4 - POSTGIS 2.2.3
> 
> Has somebody experiencied sometihng like that? 
> Could anyone help us, please?
> 
> Best regards
> 
> -- 
> 
> Fred
> 
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J. Gustavo
-- 
Jorge Gustavo Rocha
Departamento de Informática
Universidade do Minho
4710-057 Braga
Tel: +351 253604480
Fax: +351 253604471
Móvel: +351 910333888
skype: nabocudnosor