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From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
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Date: Sun, 13 Dec 2020 19:30:34 +0100
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Subject: Re: [Tarantool-patches] [PATCH v2 3/3] sql: update temporary file
 name format
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To: Leonid Vasiliev <lvasiliev@tarantool.org>, imeevma@tarantool.org, korablev@tarantool.org, sergos@tarantool.org, m.semkin@corp.mail.ru
Cc: tarantool-patches@dev.tarantool.org

Thanks for the patch!

On 11.12.2020 15:49, Leonid Vasiliev via Tarantool-patches wrote:
> The bug was consisted in fail when working with temporary files
> created by VDBE to sort large result of a `SELECT` statement with
> `ORDER BY`, `GROUP BY` clauses.
> 
> Whats happen (step by step):
> - We have two instances on one node (sharded cluster).
> - A query is created that executes on both.
> - The first instance creates the name of the temporary file and
>   checks a file with such name on existence.
> - The second instance creates the name of the temporary file
>   (the same as in  first instance) and checks a file with such name
>   on existence.
> - The first instance creates a file with the `SQL_OPEN_DELETEONCLOSE`
>   flag.
> - The second instance opens(try to open) the same file.
> - The first instance closes (and removes) the temporary file.
> - The second instance tries to work with the file and fails.
> 
> Why did it happen:
> The temporary file name format has a random part, but the random
> generator uses a fixed seed.
> 
> When it was decided to use a fixed seed:
> 32cb1ad298b2b55d8536a85bdfb3827c8c8739e1

To reference a commit we also usually include commit title in
("...") after the hash.

The patch itself looks good.