[teiid-issues] [JBoss JIRA] (TEIID-4029) After terminating long running queries remains CPU load > 100% on JBoss java process

[Kylin Soong (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-4029?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13174058#comment-13174058 ] 

Kylin Soong commented on TEIID-4029:
------------------------------------

After some investigation, I think the issue caused by wrong operation in design time with Teiid Designer.

Customer want to merge/union two tables, but not trigger the union, I guess if design correct, there should be SQL like 
{code}
SELECT a."1", a."2", a."3", a."4", a."5", a."6", a."7", a."8", a."9", a."10", a."11", a."12", a."13", a."14", a."15", a."16", a."17", a."18", a."19", a."20" FROM ViewModel.csv1 AS a UNION ALL SELECT b."1", b."2", b."3", b."4", b."5", b."6", b."7", b."8", b."9", b."10", b."11", b."12", b."13", b."14", b."15", b."16", b."17", b."18", b."19", b."20" FROM ViewModel.csv2 AS b;
{code}

In my test, "select * from combinedcsv" will continue several mins due to Printstream output, but "select count(*) from combinedcsv" will get result in several seconds.

> After terminating long running queries remains CPU load > 100% on JBoss java process
> ------------------------------------------------------------------------------------
>
>                 Key: TEIID-4029
>                 URL: https://issues.jboss.org/browse/TEIID-4029
>             Project: Teiid
>          Issue Type: Bug
>          Components: Server
>    Affects Versions: 8.7.4
>            Reporter: Colin Mondesir
>            Assignee: Steven Hawkins
>             Fix For: 8.12.x
>
>         Attachments: Archive.zip, Case01593403.java, heap.1, heap.2, heap.3, heap.4, heap.5, highcpu-vdb.xml
>
>
> Once the request is submitted the CPU% load on the server remains > 100% despite cancelling the request and terminating the session. The only way I have found to bring the %CPU back to "normal" is to re-start the JDV instance.
> 1. Created two files file1.csv (1M rows) and file2.csv (1M rows)
> 2. Created two source and view models and VDB
> SQL statement is a carthesion product
> 3. Deploy VDB
> 4. select * from combinedcsv from SQL scrapbook on cancelLongRunningQueries VDB
> 5. Goto admin console 
> 6. Go to the cancelLongRunningQueries VDB
> 7. Goto tab Requests and select Terminate
> 8. Goto tab Sessions and select Terminate JDBC session
> 9. CPU% load on JBoss java process remains > 100%



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