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
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