Critical Description
Dynamic partitioning with HCatalog has been broken as a result of HCATALOG-500 trying to support user-set paths for external tables.
The goal there was to be able to support other custom destinations apart from the normal "hive-style" partitions. However, it is not currently possible for users to set paths for dynamic ptn writes, since we don't support any way for users to specify "patterns"(like, say "${rootdir}/$v1.$v2/") into which writes happen, only "locations", and the values for dyn. partitions are not known ahead of time. Also, specifying a custom path messes with the way dynamic ptn. code tries to determine what was written to where from the output committer, which means that even if we supported patterned-writes instead of location-writes, we still have to do some more deep diving into the output committer code to support it.
Thus, my current proposal is that we honour writes to user-specified paths for external tables ONLY for static partition writes - i.e., if we can determine that the write is a dyn. ptn. write, we will ignore the user specification. (Note that this does not mean we ignore the table's external location - we honour that - we just don't honour any HCatStorer/etc provided additional location - we stick to what metadata tells us the root location is.
Attachments
Attachments
Issue Links
- is related to
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HCATALOG-500 HCatStorer should honor user-specified path for external tables
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- Closed
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- relates to
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- Resolved
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