I am sure it was just lack of scope; since the virtual tables can be any SQL query - it was probably not obvious how to integrate a select hint? If you have a join for example which select would you like to add the hint to? Or would you like to create a subquery and do the select on the result?
It sounds like a good idea though if you are interested in adding the functionality. -- Jody Garnett On Tue, Dec 13, 2022 at 12:36 PM Uhrig, Stefan via GeoTools-Devel < geotools-devel@lists.sourceforge.net> wrote: > Hi all, > > > > Recently, a group of GeoServer users on HANA requested the possibility to > append hints to SQL queries. Luckily, there was already > SQLDialect#handleSelectHints(). So, I could just override the method in > HanaDialect and append the hints to the query, which I did in [GEOT-7230] ( > https://github.com/geotools/geotools/pull/4064). > > > > Now the group of users who requested the feature noticed that it works for > common GeoServer layers, but not for GeoServer views, which are based on > GeoTools’ VirtualTable. I investigated and found that JDBCDataStore > deliberately blocks the addition of search hints ( > https://github.com/geotools/geotools/blob/29394a11ce3128a625f5251abeb9b0b09cc0105b/modules/library/jdbc/src/main/java/org/geotools/jdbc/JDBCDataStore.java#L3505 > ). > > > > I found that the SQLDialect#handleSelectHints() has been introduced with > “[GEOT-4707] Add a flag to force spatial index usage in sql server” ( > https://github.com/geotools/geotools/pull/371/files). Adding search hints > to VirtualTable queries was blocked from the start. > > > > Does someone know why search hints are not added to VirtualTable queries? > > > > In the HANA use case, I could not identify any reason yet why the addition > of search hints should be blocked. I might oversee something though. If > there is no urgent reason to block search hints in VirtualTable queries, > what would be a good way to support search hints on VirtualTable queries in > a SQLDialect? Would the introduction of an additional function like > appendSearchHintsToVirtualTableQueries() be acceptable? > > > > Thank you and best regards, > > Stefan > > > > > _______________________________________________ > GeoTools-Devel mailing list > GeoTools-Devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geotools-devel >
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