[tarantool-patches] Re: [PATCH] sql: disallow to rename space if it is referenced by view

["n.pettik" <korablev@tarantool.org>]

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> On 11 Dec 2018, at 10:02, Konstantin Osipov <kostja@tarantool.org> wrote:
> 
> * Nikita Pettik <korablev@tarantool.org <mailto:korablev@tarantool.org>> [18/12/09 20:53]:
>> Before this patch it was allowed to rename space which is referenced by
>> a view. In turn, view contains SELECT statement in a raw form (i.e. as a
>> string) and it is not modified during renaming routine. Hence, after
>> renaming space still has referencing counter > 0, but no usage of view
>> is allowed (since execution of SELECT results in "Space does not
>> exist"). To avoid such situations, lets ban renaming space if its view
>> reference counter > 0.
>> 
>> Note that RENAME is ANSI extension, so different DBs behave in this case
>> in different ways - some of them allow to rename tables referenced by a
>> view (PostgreSQL), others - don't (Oracle).
>> 
>> Closes #3746
>> ---
>> Branch: https://github.com/tarantool/tarantool/tree/np/gh-3746-view-rename
>> Issue: https://github.com/tarantool/tarantool/issues/3746
>> 
>> src/box/alter.cc       | 6 ++++++
>> test/sql/view.result   | 6 ++++++
>> test/sql/view.test.lua | 3 +++
>> 3 files changed, 15 insertions(+)
>> 
>> diff --git a/src/box/alter.cc b/src/box/alter.cc
>> index 029da029e..f3b267401 100644
>> --- a/src/box/alter.cc
>> +++ b/src/box/alter.cc
>> @@ -1823,6 +1823,12 @@ on_replace_dd_space(struct trigger * /* trigger */, void *event)
>> 				  space_name(old_space),
>> 				  "can not convert a space to "
>> 				  "a view and vice versa");
>> +		if (strcmp(def->name, old_space->def->name) != 0 &&
>> +		    old_space->def->view_ref_count > 0)
>> +			tnt_raise(ClientError, ER_ALTER_SPACE,
>> +				  space_name(old_space),
>> +				  "can not rename space which is referenced by "
>> +				  "view");
> 
> Please specify which view is referencing this space in the error
> message.

If I could do it without over-engineering, I would have already done it.
As you may see, space features only reference counter, so to get name
of view we should iterate over all VIEWs and compile SELECT for each VIEW.

> -- 
> Konstantin Osipov, Moscow, Russia, +7 903 626 22 32 <tel:+7%20903%20626%2022%2032>
> http://tarantool.io <http://tarantool.io/> - www.twitter.com/kostja_osipov <http://www.twitter.com/kostja_osipov>

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