You can't execute queries until the end of the 'atomic' block

[#1]

Hi,

I am getting above error from Hive while trying to query a table.

This is coincidentally during an insert operation on the table...

does it mean I cant access the table while a hive insert operation is ongoing...?

table contains lots of rows partitioned by two columns

[#2 · Accepted solution]

Hi,

I don't see any errors posted in the post, can you please share again?

In general, Hive have locking mechanism enabled, so when INSERT is happening on a table, an exclusive lock will be place on the table and any query tries to run against the same table will have to wait, and there is a timeout to control how long the wait will be, and the query will fail with error if timeout exceeded, otherwise it will just keep waiting until lock is released.

So to understand more on the issue, I need to see what error was reported.

Cheers
Eric

[#3 · Accepted solution]

Hi,

I don't see any errors posted in the post, can you please share again?

In general, Hive have locking mechanism enabled, so when INSERT is happening on a table, an exclusive lock will be place on the table and any query tries to run against the same table will have to wait, and there is a timeout to control how long the wait will be, and the query will fail with error if timeout exceeded, otherwise it will just keep waiting until lock is released.

So to understand more on the issue, I need to see what error was reported.

Cheers
Eric

[#4]

Hi ,

im facing same issue , 

attached is the error screenshot

[#5]

I am facing the same error when executing sql query through hue server。Now I have no idea to solve the error。 

Please。

[#6]

Hi,

Im also facing same issue ,

increased connections numbers to HUE DB, still issue exits. 

Thanks,

SS

[#7]

Can you check "show locks" if the table is acquired EXCLUSIVE lock ?

[#8]

Hi,

No its not acquiring lock , result was empty set  in hue DB.

Thanks,

syed

[#9]

DOes the same issue happen when you run via beeline ? I researched ,I found this occurs only in hue.

[#10]

Hi,

yes its happening at hue browser only

[#11]

Hue is unable to handle the slow responses from Hive servers and hence the error. This happens when Hive is unable to return the query handle to Hue in a timely manner. So, the ideal solution here would be to investigate Hive slowness and not Hue.

Hue relies on server_conn_timeout parameter in its configuration (default 120s), after which the active sessions with hiveserver2 is teared down. 

If Hue is using MySQL as the underlying DB, then we can tweak the innodb-lock-wait-timeout to be greater than the server_conn_timeout in Hue's configuration, that way we get fail-fast system and the locked tables are released. Please note that this is only a workaround until the cause of Hive performance issue is found and remediated.