Thanks for the reply Julian! I should post more details: right now we have a Metadata class which implements the Metadata spec. All of that seems to work fine. Where we are stuck is in how to read the information_schema metadata from JDBC into the planner. One hackish solution is to open a DB connection when our Metadata getter is called on TableScan, and run a query against the underlying database. However, is there existing functionality to read in external statistics and metadata - for example things like table statistics.
Madhav On Mon, Nov 18, 2019 at 8:42 PM Julian Hyde <[email protected]> wrote: > May need to be a new type of metadata (i.e. a class that implements > Metadata and is acquired via RelMetadataQuery) [1] [2]. > > Julian > > [1] > https://calcite.apache.org/apidocs/org/apache/calcite/rel/metadata/Metadata.html > < > https://calcite.apache.org/apidocs/org/apache/calcite/rel/metadata/Metadata.html> > > > [2] > https://calcite.apache.org/apidocs/org/apache/calcite/rel/metadata/package-summary.html > < > https://calcite.apache.org/apidocs/org/apache/calcite/rel/metadata/package-summary.html> > > > > On Nov 18, 2019, at 5:40 PM, Madhav Suresh <[email protected]> > wrote: > > > > Hi All, > > > > We have security type information that we want to bring into the > optimizer. > > Consider the query: > > SELECT a FROM a,b where a.id=b.id AND a.p > 10; > > We want the optimizer to know that a.id, b.id are "public" attributes, > and > > a.p is a private attribute. Currently we have type information stored > > inform information_schema in postgres. Right now our prototype considers > > privacy as a RelTrait. We are stuck on what the best way to read this > > information is. Is there a similar example, or template on how to read in > > table metadata into calcite? > > > > Madhav > >
