Re: "cancelling statement due to user request error" occurs but the transaction has committed.

On Fri, Jun 6, 2014 at 2:11 PM, Naoya Anzai <anzai-naoya@mxu.nes.nec.co.jp> wrote:
>
> Hi All,
>
> When log_duration is true ( or log_min_duration_statement>=0 ),
> If a transaction has internally been commited receives a SIGINT signal
> then a query cancellation error is output.
>
> For example,
> 1. A query like a TRUNCATE is removing bigger table files.
> 2. The session receives SIGINT signal.
> 3. Query cancellation error occurs.
> 4. But the query has commited.
>
>
> naoya=# truncate hoge;
> Cancel request sent
> ERROR:  canceling statement due to user request
> naoya=# select count(*) from hoge;
>  count
> -------
>      0
> (1 row)
> ---
>
> This is because  ProcessInterrupts function is called by errfinish ( in query-duration ereport).
>
> I think this cancellation request must not interrupt the internal commited transaction.
>
> This is because clients may misunderstand "the transaction has rollbacked".