Github user dongjoon-hyun commented on the pull request:
https://github.com/apache/tajo/pull/543#issuecomment-94274754
Hi, @jihoonson . I found a related description in PostgresSQL documentation.
http://www.postgresql.org/docs/9.4/static/queries-order.html
*After a query has produced an output table (after the select list has
been processed) it can optionally be sorted*. If sorting is not chosen, the
rows will be returned in an unspecified order. The actual order in that case
will depend on the scan and join plan types and the order on disk, but it must
not be relied on. A particular output ordering can only be guaranteed if the
sort step is explicitly chosen.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
