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https://issues.apache.org/jira/browse/IMPALA-9763?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17370211#comment-17370211
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ASF subversion and git services commented on IMPALA-9763:
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Commit 96952d1851f3ed326d215a582e6b92f3270c23b8 in impala's branch
refs/heads/branch-4.0.0 from liuyao
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=96952d1 ]
IMPALA-9763: builtin functions throw unknown exception
There is a read-write contention in FunctionName#analyze()
when a FunctionName object is shared to two threads: check if there
is a builtin function in wrong database, when 'db_' is temporarily
modified by the other thread.
This patch fix this issue. For analyze FunctionName, if no database is
specified, check builtinDb first; if FunctionName is not in builtinDb,
set the database to defaultDb.Avoid setting the database of
FunctionName to a temporary value
Detailed description:
This problem is caused by shallow copies. In the function
FromClause::analyze(Analyzer analyzer), if the table is FeView,
the analyzer will clone SelectStmt from the view's MetaData,
which should be a deep copy. But in the copy constructor of
FunctionCallExpr, fnName_ = other.fnName_, this is a shallow copy,
which makes the fnName_ of multiple queries refer to the same block of
memory. When the query is analyzed, the database of fnName_ will be
set.But this will change the fnName_ of other queries.
For example:
create view1 as select coalesce(col1, 2) from table1;
User A and User B check the same view1 at the same time. When
user A’s query is analyzed, it runs to db_ = analyzer.getDefaultDb() of
FunctionName::analyze. User B’s query is also analyzed and runs to
FunctionCallExpr::analyzeImpl, and just completed FunctionName::analyze
at this time, the step of user A's db_ = analyzer.getDefaultDb() will
change the db_ attribute of user B's fnName_ to defaultDb, and then
user B will continue to check whether the function is defaultDb,
Throw an exception: coalesce() unknown for database .......
Change-Id: Ifd77f5a7cd9a674340770233fe26eb5dc26e666a
Reviewed-on: http://gerrit.cloudera.org:8080/17604
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
> impala查询偶尔报错 -- Impala queries occasionally report errors
> ---------------------------------------------------------
>
> Key: IMPALA-9763
> URL: https://issues.apache.org/jira/browse/IMPALA-9763
> Project: IMPALA
> Issue Type: Bug
> Components: Catalog
> Affects Versions: Impala 3.2.0
> Reporter: liqinglong
> Assignee: liuyao
> Priority: Major
> Labels: bug
> Fix For: Impala 3.2.0
>
> Attachments: 1.png, 2.png, 3.png, long_text_2020-05-19-17-00-29.txt
>
>
> 用 superset 链接impala
> 视图查询，打开看板偶尔会报如图3的的错，都是在解析SQL时找不到内置函数的错，但是强制刷新看板重新查询又不再报错，连续多次查询都会报，但是过一会再强制刷新查询又会报错，前后查询SQL语句一致，见图1和图2，日志见附件文档，能不能帮忙提一下意见是哪方面bug
>
> Adding the Google-translated English version (laszlog):
> Use the superset to link the impala view query. When you open the kanban
> board, you will occasionally report the error as shown in Figure 3. It is the
> error that you cannot find the built-in function when parsing the SQL.
> However, after a while, you will be forced to refresh the query again and you
> will get an error. The query SQL statement is consistent before and after,
> see Figure 1 and Figure 2, the log is in the attached document, can you help
> to mention what is the bug?
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