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From Apekshit Sharma <a...@cloudera.com>
Subject Re: Assignment Manager and clock advance.
Date Wed, 03 Jan 2018 00:37:17 GMT
Hi Sergey,

Interesting test and find. Makes total sense too.
However, in real world case, any put in meta table itself will take more
than a ms, and then we have lot of Procedure framework and other logic in
between meta accesses which would make this scenarios impossible.
Specifically, there a lot of processing in between adding rows from
CreateTableProcedure and trying to access it in children AssignProcedure(s).

-- Apy

On Tue, Jan 2, 2018 at 3:58 PM, Sergey Soldatov <sergeysoldatov@gmail.com>
wrote:

> Hi,
> Not sure whether we may consider that as a bug, but I found an interesting
> dependency of AM2 on clock advancing. A simple operation such as create
> table is unable to perform with the same current_time value:
>
> public void testCreateTable() throws IOException {
>   EnvironmentEdgeManager.injectEdge(new EnvironmentEdge() {
>     volatile int curTime = 1000;
>
>     @Override
>     public long currentTime() {
>
>       return curTime;
>     }
>   });
>   final TableName tableName = TableName.valueOf("test");
>   TEST_UTIL.createTable(tableName, HConstants.CATALOG_FAMILY).close();
> }
>
> and fails with a TableNotFound exception. The reason is that between
> transitions we get table information from meta using Get with the exclusive
> current timestamp. Could it be a potential problem (i.e. the system capable
> to execute all that transition stuff in less than 1 ms)?
>
> Thanks,
> Sergey
>



-- 

-- Appy

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