Issue with st_estimatedextent function ??

[Bo Victor Thomsen]

Hi list -

I'm using Postgres/Postgis as a data repository for QGIS - and it 
normally just works.. However I'm getting errors with tables having long 
names, for example:
/*
fdc_results.bygningskade_stormflod_rcp85_2100_t100_ssp3_7_0_20251119164
*/
(Schema-name length: 11, table-name length: 59)

I have tracked the issue using the log facility in QGIS. It shows, that 
QGIS intermittently executes a SQL command:

/*SELECT 
st_estimatedextent('fdc_results','bygningskade_stormflod_rcp85_2100_t100_ssp3_7_0_20251119164','geom')*/

which results in an error: *ERROR: invalid name syntax*

If I change the table name to:

/*fdc_results.bygningskade_stormflod_rcp85_2100_t100_ssp3_7_0 
*/(Schema-name length: 11, table-name length: 47)

the error disappears.

I've done some testing and could replicate the error (and non-error) 
situation in PGAdmin

Further testing shows that if the sum of the character lengths of the 
schema- and table-name is larger than 58 the function will stop with an 
error. Otherwise it returns a result like:

"BOX(716701.25 6167151,720533.9375 6174220)"

It's my understanding, that the maximum length of a tablename in 
PostgreSQL is 63. This same limit applies for every type of identifier 
in Postgres. Am I wrong to assume this? Or is there an issue with name 
lengths in the /**/PostGIS st_estimatedextent/**/ function??

(It might be a coincidence but if you express the tablename like this : 
/*"*//*fdc_results"."bygningskade_stormflod_rcp85_2100_t100_ssp3_7_0*//*", 
*/the total length is 63)

PostgreSQL version: "PostgreSQL 17.4 on x86_64-windows, compiled by 
msvc-19.42.34436, 64-bit"

PostGIS version: "3.5 USE_GEOS=1 USE_PROJ=1 USE_STATS=1"

-- 
Med venlig hilsen / Best regards

Bo Victor Thomsen
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