Hue 4.7: Hive LLAP/Tez sessions management revamp

#1

Following the HUE 4.7 release notes, one of the new changes is

Hive LLAP/Tez sessions management was revamped in order to support more than one query running concurrently

How is this currently realized and what exactly does this mean? Does this somehow allow running multiple queries simultaneously from one window? If that’s the case, I’ve upgraded the HUE, but cannot see a functionality like this. Before the upgrade it was only possible to do this by running HUE in separate browser tabs for every concurrent query (at least of what I’m aware).

Or am I understanding this change incorrectly? Is there a more detailed explanation of this upgrade somewhere?

Thanks!

#2

Queries issues by Hue under the cover (e.g. list tables in the left SQL assist) are all issued in their own session.
Opening a new Editor opens a new dedicated session so that the user can type its query and they don’t conflict with each other. It is still one query at the time as Hive 4 does not support more than one.

Before it used to “randomly” open a few sessions for the user and pick “idle” ones which resulted in non predicable behaviors and flaky bugs (e.g. when running several sequential queries…)

#3

Thanks. I’ve noticed that “max_number_of_sessions” errors started popping up after 4.7 update, probably due to this update. Tried different values, but eventually had to resort to setting it to -1. Are there any recommendations behind this, or will -1 be fine?

#4

IIRC max_number_of_sessions=1 should be the recommended. Did you get issues with it?