A number of "see also" sorts of references point to related topics in the CDH doc library. This work item is for reorg and simplication to get rid of many <xref> tags that are unused by the standalone Impala docs, and many http:// links pointing to doc pages on cloudera.com.
We always preserved the ability to get a clean Impala-only doc build be conditionalizing them like so:
The Impala-only doc build uses the 'standalone' condition, which means that only the link that resolves to the http:// URL is processed, and the missing sg_hive_sql.xml file doesn't cause a doc build error.
This work item is to use the DITA <keydef> tag and keyref= attribute for <xref> tags to make these external links easier to genericize. That DITA facility uses a side file similar to a .h where link destinations are centralized. The double <xref> tags with different conditions are condensed down to something like:
and the side file can be customized to make the link point to a local .xml file, a remote http:// URL, or even become plain text instead of a link.
(This mechanism relies on the same <keydef> tag / keyref= attribute that we use for short text substitutions like for the Impala release numbers. That tagging idiom does double duty.)