vtlim commented on code in PR #16712: URL: https://github.com/apache/druid/pull/16712#discussion_r1678492324
########## docs/querying/lookups.md: ########## @@ -50,6 +50,10 @@ Other lookup types are available as extensions, including: - Globally cached lookups from local files, remote URIs, or JDBC through [lookups-cached-global](./lookups-cached-global.md). - Globally cached lookups from a Kafka topic through [kafka-extraction-namespace](./kafka-extraction-namespace.md). +:::info +[Multi-value dimensions](multi-value-dimensions.md), MVDs, are not supported as keys in lookups. To map the MVD `["A", "B", "C"]` to the value `x` in your lookup, flatten the MVD before using it as a lookup. Then map each element of the MVD to the value. Your lookup will have separate key-value pairs for each element of the MVD: `"A": "x"`, `"B": "x"`, and `"C": "x"`. Review Comment: ```suggestion [Multi-value dimensions](multi-value-dimensions.md) (MVDs) are not supported as keys in lookups. For example, to map the MVD `["A", "B", "C"]` to the value `x` in your lookup, flatten the MVD and map each element of the MVD to the value. Your lookup will have separate key-value pairs for each element of the MVD: `"A": "x"`, `"B": "x"`, and `"C": "x"`. ``` -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
