Hi Erwan, databases are not the only source of data. A function must be able to work in memory first, so that it works with shapefiles, elasticsearch, mongo and so on as well. Then there can be an optimization translating them down to SQL. There is a filter splitter slicing filters in two parts, one that can be encoded down into the datasources, and one that will run in memory as a post filter. If the datastore filter capabilities declare support for the function, it will be encoded and executed in the database, not in memory, regardless of whether it has code to be executed in memory. Each datastore can decide to translate the bits of filters and functions in a different way, based on what can or cannot be translated down to native filtering.
Cheers Andrea On Fri, Apr 16, 2021 at 4:53 PM Erwan Bocher <erwan.boc...@univ-ubs.fr> wrote: > Hi Andrea, > > I'm extending some filter functions to be compliant with SFSSQL. > > What about adding this feature in the main geotools module and declare > those new functions in the DB FilterToSQLHelper classes ? > > If we have an external module, these functions will not be optimized in > SQL. > > Erwan > > > Le 29/12/2020 à 15:45, Andrea Aime a écrit : > > On Wed, Dec 23, 2020 at 3:55 PM Erwan Bocher <erwan.boc...@univ-ubs.fr> > wrote: > >> This is my idea : add support to SFS names in CQL (filter and expression) >> without breaking anything in the parser ;-) >> > > As long as they are handled "in memory" I have no objection, just make > sure the semantics is the same as the current functions, if not, create a > separate one. > What alarmed me was the possibility of blindly translating it down to SQL. > That should be done on a database by database basis, checking what they > support, and under which semantics. > > Different semantics between CQL and SQL is an annoying source of issues. > For example, CQL has two valued logic, but SQL has three valued logic (null > gets its own category). > There is a filter translator we created to make sure the SQL generated > behaves in a two-way, which caused several people to complain about > performance (the generated > queries do a number of null checks, and harder to read and optimize) > > Cheers > Andrea > > == GeoServer Professional Services from the experts! Visit > http://goo.gl/it488V for more information. == Ing. Andrea Aime @geowolf > Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054 Massarosa > (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339 8844549 > http://www.geo-solutions.it http://twitter.com/geosolutions_it > ------------------------------------------------------- *Con riferimento > alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 - > Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni > circostanza inerente alla presente email (il suo contenuto, gli eventuali > allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i > destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per > errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le > sarei comunque grato se potesse darmene notizia. This email is intended > only for the person or entity to which it is addressed and may contain > information that is privileged, confidential or otherwise protected from > disclosure. We remind that - as provided by European Regulation 2016/679 > “GDPR” - copying, dissemination or use of this e-mail or the information > herein by anyone other than the intended recipient is prohibited. If you > have received this email by mistake, please notify us immediately by > telephone or e-mail.* > > -- > Ingénieur de Recherche CNRS - HDR, > Laboratoire Lab-STICC – UMR 6285 > Equipe DECIDE > Institut Universitaire de Technologie de Vannes > 8, Rue Montaigne - BP 561 56017 Vannes Cedex > T: +33 2 97 62 64 92 > W: https://cv.archives-ouvertes.fr/erwan-bocher > W: http://www.labsticc.fr > > -- Regards, Andrea Aime == GeoServer Professional Services from the experts! Visit http://goo.gl/it488V for more information. == Ing. Andrea Aime @geowolf Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054 Massarosa (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339 8844549 http://www.geo-solutions.it http://twitter.com/geosolutions_it ------------------------------------------------------- *Con riferimento alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 - Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni circostanza inerente alla presente email (il suo contenuto, gli eventuali allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le sarei comunque grato se potesse darmene notizia. This email is intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. We remind that - as provided by European Regulation 2016/679 “GDPR” - copying, dissemination or use of this e-mail or the information herein by anyone other than the intended recipient is prohibited. If you have received this email by mistake, please notify us immediately by telephone or e-mail.*
_______________________________________________ GeoTools-GT2-Users mailing list GeoTools-GT2-Users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
