Inconsistent property names for "druid.metadata.storage.tables.xxx"

[guobingkun]

druid.metadata.storage.tables.segmentTable, druid.metadata.storage.tables.ruleTable and druid.metadata.storage.tables.configTable are actually ignored by Druid, because the JsonProperty specified in MetadataStorageTablesConfig are different from those.

This PR updates the document and adds a serde test.

[himanshug]

I think the question here is whether to correct the documentation or the code. this PR updates the doc with corrected names (which are consistent with other table names) and that seems fine to me

[himanshug]

this check is very fragile, individual asserts above should be good enough.

[guobingkun]

Done

[nishantmonu51]

+1 to correct the docs instead of modifying the code.

[himanshug]

LGTM

but, here is a caveat: if someone used something like
druid.db.tables.configTable=ABC
in their old properties file, which wouldn't have taken any effect due to the code bug. However, if they run ConvertProperties tool, that will be converted to correct property and suddenly ABC will become the config table for them instead of druid_config. This scenario is highly improbable, so I think its fine.

@xvrl @drcrallen what do you think?

[fjy]

I think it is fine to merge this fix and make a note of it in the forums as well as documenting it. I dont know of any installation that actually overrides this configs, but it may be good to ask

[guobingkun]

Hi @fjy , I posted this a while ago https://groups.google.com/forum/#!topic/druid-development/9tHdxNbMPoE