Re: [Tarantool-patches] [PATCH 4/5] sql: replace control pragmas by SET

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

On 27/11/2019 12:05, Mergen Imeev wrote:
> On Wed, Nov 27, 2019 at 01:51:50PM +0300, Konstantin Osipov wrote:
>> Why is it not possible to make the settings system view updatable,
>> if you decided to go with adding such a view anyway?
>>
> The sysview is empty. Not sure we need to make this
> updatable.

As I said in the very beginning, you could implement DML
operations for the space, and update struct session flags
via them.

Currently we have 'single interface to access the settings',
but we can update them only via SQL.

>> Usually, if one allows SET statement, SET option_name (without 
>> "= new_value") prints the current setting. This does the job and
>> makes the "_vsettings" system view unnecessary.
>>
>> Don't you think that having to use one piece of syntax to query a
>> value and entirely different piece to assign it is, ehm,
>> inconsistent, hard to learn & remember, and eventually hard to
>> use?
>>
> You are right. This was also pointed by Vlad in previous
> review:
> "2. Ok, but now it looks really unusable when a user want's to
> learn an option value. I will create a ticket, if this patchset
> will be pushed and nobody will care about usability beforehand."
> 
> Personally, I think this is easy to fix, and your
> suggestion is good. In fact, I can fix this in this
> patch-set if Vlad and Nikita agree with this solution.
> 

I am ok with that. But that really returns us to the point,
how PRAGMAs worked - exactly the same, AFAIR.