drill-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Abdel Hakim Deneche <adene...@maprtech.com>
Subject Re: OK_NEW_SCHEMA: changed schema or maybe just new report?
Date Fri, 02 Oct 2015 19:38:16 GMT
Some operators like external sort or window functions will double check to
make sure the schema really changed before throwing a schema-change
exception. But others, like streaming aggregate or hash aggregate, don't
check and will throw a schema-change exception even if the schema didn't
really change.

so I guess it's a combination of both

On Fri, Oct 2, 2015 at 11:26 AM, Daniel Barclay <dbarclay@maprtech.com>

> Is OK_NEW_SCHEMA intended to signal that the new schema is actually
> changed from any previous schema, or is it intended only to signal
> that there's a new (report of the) schema, but the new schema isn't
> necessarily different from any previous schema)?
> Are callers (of XxxBatch next() methods) that receive OK_NEW_SCHEMA
> responsible for checking whether the new schema is the same as the old
> schema (or, more generally, can be handled by the caller) and avoiding
> throwing a schema-change exception in that case?
> Or are callees (XxxBatch next() methods) responsible for not returning
> OK_NEW_SCHEMA if the new schema is the same as the previous schema?
> (Or is it some combination?)
> Thanks,
> Daniel
> --
> Daniel Barclay
> MapR Technologies


Abdelhakim Deneche

Software Engineer


Now Available - Free Hadoop On-Demand Training

  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message