If that's all the meta info to store, anything not in the tile file itself would be overkill. Looks like we only need 2 bits for a full/empty/unknown flag. On Linux and MacOS it should be possible to use extended file attributes, dunno about Windows. I'm pretty sure S3 also supports custom object metadata.
Not fond of the idea of side-car files, though could be an opt-in compromise due to overhead (would require a check for existence for all tiles). 2c. On Thu, 27 May 2021 at 07:47, Andrea Aime <[email protected]> wrote: > Hi all,, > while reviewing the OGC API Tiles spec, found these bits about returning > HTTP headers, > telling the client that a given portion of the tile cache might be fully > empty, or completely solid, > from that point on: > > > https://github.com/opengeospatial/ogcapi-tiles/blob/master/core/standard/recommendations/tileset/REC_tc-deepfullempty.adoc > > If we had to implement this (it's just a recommendation) then we'd need to > store meta-information around > the tile, something the BlobStore interface and TileObject have no room > for right now. > > FileBlobStore/AWS wise I guess sidecar files could be used... for some > formats headers could be an option too, > but don't think every tile format allows for that option, or might have > limitation regarding the type and size > of info that can be stored in the headers. > > Has anyone worked on something like this before? > > 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.* > _______________________________________________ > Geoserver-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geoserver-devel > -- Gabriel Roldán
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