besquared opened a new issue, #4797: URL: https://github.com/apache/arrow-adbc/issues/4797
PostgreSQL result descriptions expose declared NUMERIC precision and scale through libpq PQfmod, but the driver currently retains PQftype and the type name without carrying the result type modifier into the Arrow field metadata. For example, SELECT 1.25::numeric(29,9) returns an exact UTF-8 numeric value, but a downstream consumer cannot distinguish its declared bounds from a result with no modifier. Exposing the existing modifier would let consumers apply their own decimal conversion policy without SQL parsing, another connection, or changes to the string transport. Proposal: preserve PQfmod for top-level numeric result columns in COPY and non-COPY execution, including ExecuteSchema and empty results. Represent it as a signed decimal metadata string, including -1 when PostgreSQL supplies no modifier. POSTGRESQL:typmod is a proposed key following POSTGRESQL:type; naming is open to review. This does not infer bounds, convert numeric values, change catalog discovery, or implement requested output schemas. Related prior discussion explicitly mentions PQfmod: https://github.com/apache/arrow-adbc/pull/758#discussion_r1224844245 . Also related: #767 and #4687. I have an implementation with native schema tests and read-only PostgreSQL integration coverage for both execution paths. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
