Обсуждение: Two PostgreSQL instances returning different output for same query

I’m a bit stumped on this one. For one of my application teams both their DEV instance and UAT instance are running pg
version12.3 in AWS RDS, and I’ve used the same psql version 13.4. 

The query is a simple:  SELECT to_jsonb(geom) FROM addresses LIMIT 1;

On both databases the geom field is of data type geometry from postgis, but the two dbs are running different versions
ofPostgis. DEV is 3.0.2 while UAT is 2.5.2, but I don’t think this is causing the issue. 

Running the query on the DEV instance produces
to_jsonb
———————————-
{“type”: “Point”, “coordinates”: [-106.54569, 31.82908]}

While running it on the UAT instance produces
to_jsonb
—————————————
“0101000020E610009000000000000000“

If I remove the to_jsonb() so the query becomes SELECT geom FROM addresses;  both output the same very long string that
theUAT instance produces for the to_jsonb() output. So UAT does not seem to be processing the to_jsonb. 

I’m thinking that there might be a GUC controlling the output format, but I can’t seem to find any references for one.

Any ideas?
Jay

Sent from my iPad

On Tue, Aug 30, 2022 at 11:21:26AM -0400, John Scalia wrote:
> I’m a bit stumped on this one. For one of my application teams both their DEV instance and UAT instance are running
pgversion 12.3 in AWS RDS, and I’ve used the same psql version 13.4.
 
> 
> The query is a simple:  SELECT to_jsonb(geom) FROM addresses LIMIT 1;
> 
> On both databases the geom field is of data type geometry from postgis, but the two dbs are running different
versionsof Postgis. DEV is 3.0.2 while UAT is 2.5.2, but I don’t think this is causing the issue.
 
> 
> Running the query on the DEV instance produces 
> to_jsonb
> ———————————-
> {“type”: “Point”, “coordinates”: [-106.54569, 31.82908]}
> 
> While running it on the UAT instance produces
> to_jsonb
> —————————————
> “0101000020E610009000000000000000“

Check installed extensions, and their versions in both dbs.

Best regards,

depesz

On 8/30/22 10:21, John Scalia wrote:

I’m a bit stumped on this one. For one of my application teams both their DEV instance and UAT instance are running pg version 12.3 in AWS RDS, and I’ve used the same psql version 13.4.

Obligatory "why are you using 12.3 when 12.11 is the latest?"  Upgrading takes all of 15 minutes.

The query is a simple:  SELECT to_jsonb(geom) FROM addresses LIMIT 1;

Are you sure that they are the same record?  (I always use ORDER BY with "LIMIT 1" when comparing records.)

John Scalia <jayknowsunix@gmail.com> writes:
> I’m a bit stumped on this one. For one of my application teams both their DEV instance and UAT instance are running
pgversion 12.3 in AWS RDS, and I’ve used the same psql version 13.4. 
> The query is a simple:  SELECT to_jsonb(geom) FROM addresses LIMIT 1;

> On both databases the geom field is of data type geometry from postgis, but the two dbs are running different
versionsof Postgis. DEV is 3.0.2 while UAT is 2.5.2, but I don’t think this is causing the issue. 

I think you're being far too hasty to reject a highly probable
explanation.  Consult the Postgis release notes to see if they
changed anything about casting-to-JSON between those two releases.

A quick look at to_jsonb's innards shows that for a non-core input type,
it will use the type's cast to JSON if there is one, while if there is
not, it will just run the type's output function and call the result a
JSON string.  This seems to fit quite well with the results you show.

            regards, tom lane

On Tue, Aug 30, 2022 at 11:21:26AM -0400, John Scalia wrote:
> I’m a bit stumped on this one. For one of my application teams both their DEV instance and UAT instance are running
pgversion 12.3 in AWS RDS, and I’ve used the same psql version 13.4.
 
> 
> The query is a simple:  SELECT to_jsonb(geom) FROM addresses LIMIT 1;
> 
> On both databases the geom field is of data type geometry from postgis, but the two dbs are running different
versionsof Postgis. DEV is 3.0.2 while UAT is 2.5.2, but I don’t think this is causing the issue.
 

Changelog for postgis 3.0.0 shows:

3687, Casts json(geometry) and jsonb(geometry) for implicit GeoJSON generation (Paul Ramsey)

looks to be very related.

Best regards,

depesz