[ovirt-devel] Fwd: [IMPORTANT] Implementing materialized views

[Yedidyah Bar David]

On Tue, Jul 18, 2017 at 1:29 AM, Martin Perina <mperina at redhat.com> wrote:
> Hello,
>
> to make things completely clear: any developer which will perform any
> changes around permissions tables need to use only predefined stored
> procedures for permissions handling. If for some reason direct SQL update is
> performed, then materialized view will not be refreshed until some
> permission stored procedure is called, which could cause strange results.

Isn't it possible to prevent such accidents somehow?

E.g., is it possible that:
1. We rename current table ("permissions") to some "private"
name (e.g. "permissions_tab")
2. We create the materialized view having the name of the
original table ("permissions")
3. We do what's needed (?) so that direct inserts/updates/deletes
on the view either fail or do the right thing.

>
> Eli has already removed all such code within patch [3], so this is just a
> warning for future.
>
> Thanks
>
> Martin
>
>
> On Mon, Jul 17, 2017 at 9:47 PM, Eli Mesika <emesika at redhat.com> wrote:
>>
>>
>> Materialized Views [1] can be used to reduce query time on complex queries
>> with low data update
>>
>> The first candidates to use this feature are all the *permission* views
>>
>> There is already a RFE [2] opened for that.
>>
>> Please make sure that each call that handles the permissions table data is
>> using the corresponding SP in dbscripts/multi_level_administration.sql
>> No direct access to the permissions table is allowed !
>>
>> In case that a direct access to the permissions table is used, you should
>> replace the code in a call to the corresponding SP as you can see in [3]
>>
>> A direct use that will not be replaced with a call to the corresponding SP
>> may cause that direct changes to the permissions table will not be reflected
>> in the
>> *permission* Materialized Views and the views will remain dirty until a
>> change that is calling one of the SPs that handle the data of the
>> permissions table is issued and cause the Materialized Views to be refreshed
>>
>> Please check your code for direct use of the permissions table and consult
>> with me if you have any questions or issues.
>>
>> Thanks
>>
>> Eli Mesika
>>
>> [1] https://wiki.postgresql.org/wiki/Materialized_Views
>> [2] https://bugzilla.redhat.com/show_bug.cgi?id=1470991
>> [3] https://gerrit.ovirt.org/#/c/79287/
>>
>>
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>
>
>
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-- 
Didi