Do hive queries executed via HUE survive a disconnect? - hive

If I fire a query to HIVE using HUE. The query is taking a long time.
Can I disconnect my browser and go home? some back tomorrow and refresh the same page and see the result?
Or should I leave the machine connected with the browser open so that I don't lose the query/MR results.

Actually I found the answer. last night I ran all my queries and went home and today morning reconnected my machine to the network and refreshed the results. I can see query results.
So we don't need to wait for the query to finish to get the results.

Related

Bigquery Cache Not Working

I noticed that BigQuery no longer cache the same query even I have chosen to use cache in the GUI (both Alpha and Classic). I didn't edit the query at all, just keep clicking run query button and every time GUI executed the query without using cache results.
It happens to my PHP script as well. Before, it was enable to use cache and came back with results very quick and now it executes the query every time even the same query has been executed minutes ago. I can confirm the behaviour in the logs.
I am wondering if there is anything changed in the last few weeks? Or some kind of account level settings control this? Because it was working fine for me.
As per official docs here cache is disable when:
...any of the tables referenced by the query have recently received
streaming inserts...
Even if you are streaming to one partition, and then querying to another, this will invalidate caching functionality for the whole table. There is this feature request opened where it is requested to be able to hit cache when doing streaming inserts to one partition but querying a different partition.
EDIT***:
After some investigation I've found out that some months ago there was an issue going on which was allowing to hit the cache even streaming inserts were being made. This was not expected behavior, and therefore it got solved in May. I guess this is the change you have experienced and what you are talking about.
Docs have not changed related to this, and they aren't/weren't incorrect. Just the previous behavior was the incorrect one.

How to kill/stop a long SQL query immediately?

I am using SQL server 2008 and its management studio. I executed a query that yields many rows. I tried to cancel it via the red cancel button, but it has not stopped for the past 10 minutes. It usually stops within 3 minutes.
What could the reason be and how do I stop it immediately ?
sp_who2 'active'
Check values under CPUTime and DiskIO. Note the SPID of process having large value comparatively.
kill {SPID value}
What could the reason be
A query cancel is immediate, provided that your attention can reach the server and be processed. A query must be in a cancelable state, which is almost always true except if you do certain operations like calling a web service from SQLCLR. If your attention cannot reach the server it's usually due to scheduler overload.
But if your query is part of a transaction that must rollback, then rollback cannot be interrupted. If it takes 10 minutes then it needs 10 minutes and there's nothing you can do about it. Even restarting the server will not help, it will only make startup longer since recovery must finish the rollback.
To answer which specific reason applies to your case, you'll need to investigate yourself.
First execute the below command:
sp_who2
After that execute the below command with SPID, which you got from above command:
KILL {SPID value}
This is kind of a silly answer, but it works reliably at least in my case:
In management studio, when the "Cancel Executing Query" doesn't stop the query I just click to close the current sql document. it asks me if I want to cancel the query, I say yes, and lo and behold in a few seconds it stops executing. After that it asks me if I want to save the document before closing. At this point I can click Cancel to keep the document open and continue working. No idea what's going on behind the scenes, but it seems to work.
If you cancel and see that run
sp_who2 'active'
(Activity Monitor won't be available on old sql server 2000 FYI )
Spot the SPID you wish to kill e.g. 81
Kill 81
Run the sp_who2 'active' again and you will probably notice it is sleeping ... rolling back
To get the STATUS run again the KILL
Kill 81
Then you will get a message like this
SPID 81: transaction rollback in progress. Estimated rollback completion: 63%. Estimated time remaining: 992 seconds.
First, you need to display/check all running queries using below query-
SELECT text, GETDATE(), *
FROM sys.dm_exec_requests
CROSS APPLY sys.dm_exec_sql_text(sql_handle)
Find Session-Id and Description for respective all running queries and then copy specific query's Session-Id which you want to kill/stop immediately.
Kill/stop specific query using Session-Id using this query:
Kill Session-id
Example:
kill 125 --125 is my Session-Id
You can use a keyboard shortcut ALT + Break to stop the query execution. However, this may not succeed in all cases.
I Have Been suffering from same thing since long time. It specially happens when you're connected to remote server(Which might be slow), or you have poor network connection.
I doubt if Microsoft knows what the right answer is.
But since I've tried to find the solution. Only 1 layman approach worked
Click the close button over the tab of query which you are being suffered of.
After a while (If Microsoft is not harsh on you !!!) you might get a window asking this
"The query is currently executing. Do you want to cancel the query?"
Click on "Yes"
After a while it will ask to whether you want to save this query or not?
Click on "Cancel"
And post that, may be you're studio is stable again to execute your query.
What it does in background is disconnecting your query window with the connection. So for running the query again, it will take time for connecting the remote server again. But trust me this trade-off is far better than the suffering of seeing that timer which runs for eternity.
PS: This works for me, Kudos if works for you too. !!!
apparently on sql server 2008 r2 64bit, with long running query from IIS the kill spid doesn't seem to work, the query just gets restarted again and again. and it seems to be reusing the spid's. the query is causing sql server to take like 35% cpu constantly and hang the website. I'm guessing bc/ it can't respond to other queries for logging in
A simple answer, if the red "stop" box is not working, is to try pressing the "Ctrl + Break" buttons on the keyboard.
If you are running SQL Server on Linux, there is an app you can add to your systray called "killall"
Just click on the "killall" button and then click on the program that is caught in a loop and it will terminate the program.
Hope that helps.
In my part my sql hanged up when I tried to close it while endlessly running. So what I did is I open my task manager and end task my sql query. This stop my sql and restarted it.
If using VSCode mssql Extension, click F1, write mssql in the prompt and choose 'cancel query', as shown in this thread about the extension.
My studio version: Microsoft SQL Server Management Studio 18
I manually closed the computer network card, and the infinite loop query was successfully terminated!

Why does a simple UPDATE statement sometimes take a few seconds to run?

Our web app automatically emails us when a page execution goes beyond a second or two with timings for running each SQL statement. We track what pages each user is browsing on each page load and this query sometimes takes a couple of seconds to run (we get a number of these automatic emails telling us a page has taken longer than a couple of seconds at the same time).
UPDATE whosonline
SET datetime = GETDATE(),
url = '/user/thepage'
WHERE username = 'companyname\theusername (0123456789)'
Any ideas what could be causing this? Normally it runs in a split second but say every week or so it takes about 2 or 3 seconds for probably a timespan of 10 seconds.
This is a very broad question and there could be a number of reasons:
Is there a pattern to what day/time in the week this happens? Maybe your db machine has just come up
How many users do you have? Are there indexes to the database?
What about the database cache? Is it configured?
How do you know it's a database delay and not a network delay? Have you tried accessing from the local database server and seen if the delays happen there too?
If you have access to SQL Profiler, you might want to run that on the statement to see if anything is happening on the server that might be causing issues. I'd also check the execution path in Management Studio/Query Analyzer if you can as well. Otherwise, if those don't turn up anything it probably is something to do with the web-side of things, not SQL.

SqlDataAdapter.Fill suddenly taking a long time

I have an application with a central DataTier that can execute a query to a data table using an SQLDataAdapter. None of this code has changed but now all queries are taking at least 10x as long to execute a query returning even one record.
The only difference is that I have been using the app in a VM but the issue has started mid way through using the application. eg, the speed issue has not manifested itself from the start of using the VM, rather half way through.
Has anyone else had an issue with the SQL Data Adapter taking a long time to fill for no reason? executing the query in Management studio it runs in less than a second.
Firewalls are disabled
ok, after another half day wasted on this it seems to be an issue relating to networking on the Virtual PC.
I have seen a massive improvement by changing the network adapter in the VM to Shared NAT and no longer experience the long delay when populating data tables.
Its obviously having an issue resolving the SQL server.
For anyone else that stumbles across this post here are the settings

Stopping SQL code execution

We have a huge Oracle database and I frequently fetch data using SQL Navigator (v5.5). From time to time, I need to stop code execution by clicking on the Stop button because I realize that there are missing parts in my code. The problem is, after clicking on the Stop button, it takes a very long time to complete the stopping process (sometimes it takes hours!). The program says Stopping... at the bottom bar and I lose a lot of time till it finishes.
What is the rationale behind this? How can I speed up the stopping process? Just in case, I'm not an admin; I'm a limited user who uses some views to access the database.
Two things need to happen to stop a query:
The actual Oracle process has to be notified that you want to cancel the query
If the query has made any modification to the DB (DDL, DML), the work needs to be rolled back.
For the first point, the Oracle process that is executing the query should check from time to time if it should cancel the query or not. Even when it is doing a long task (big HASH JOIN for example), I think it checks every 3 seconds or so (I'm looking for the source of this info, I'll update the answer if I find it). Now is your software able to communicate correctly with Oracle? I'm not familiar with SLQ Navigator but I suppose the cancel mechanism should work like with any other tool so I'm guessing you're waiting for the second point:
Once the process has been notified to stop working, it has to undo everything it has already accomplished in this query (all statements are atomic in Oracle, they can't be stopped in the middle without rolling back). Most of the time in a DML statement the rollback will take longer than the work already accomplished (I see it like this: Oracle is optimized to work forward, not backward). If you are in this case (big DML), you will have to be patient during rollback, there is not much you can do to speed up the process.
If your query is a simple SELECT and your tool won't let you cancel, you could kill your session (needs admin rights from another session) -- this should be instantaneous.
When you cancel a query, the Oracle client should send OCIBreak() but this isn't implemented on a Windows server, that could be the cause.
Also, have your DBA check the value of SQLNET.EXPIRE_TIME.