[Tarantool-patches] [PATCH v2 3/3] sql: update temporary file name format

[Nikita Pettik]

Pushed this patch (not the whole patch-set!) to master, 2.6 and 2.5 branches
(CI status was green on the branch). Corresponding changelogs are updated.
As a follow-ups I hope to see:
 - test case (mb with error injections);
 - #5625;
 - patch introducing missing diags in SQL OS internals.

> Hi! Thank you for the review.
> 
> On 13.12.2020 21:30, Vladislav Shpilevoy wrote:
> > 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.
> 
> Changed to:
> 
> When it was decided to use a fixed seed:
> 32cb1ad298b2b55d8536a85bdfb3827c8c8739e1
> ("sql: drop useless code from os_unix.c")
> 
> > 
> > The patch itself looks good.
> >