Re: proposal: session server side variables

2017-02-01 6:42 GMT+01:00 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:

>
>
> 2017-02-01 6:05 GMT+01:00 Michael Paquier <michael(dot)paquier(at)gmail(dot)com>:
>
>> On Wed, Jan 11, 2017 at 10:42 PM, Craig Ringer <craig(at)2ndquadrant(dot)com>
>> wrote:
>> > There is no code yet. Code review and testing is where things get
>> firmer.
>> >
>> > My personal stance right now is that I'd like to see catalog-decared
>> typed
>> > variables. I would prefer them to be transactional and would at least
>> oppose
>> > anything that didn't allow future room for that capability. I'd prefer
>> that
>> > non-transactional vars be clearly declared as such.
>> >
>> > In the end though... I'm not the one implementing it. I can have some
>> > influence through the code review process. But it's whoever steps up
>> with a
>> > proposed implementation that has the biggest say. The rest of us can
>> say yes
>> > or no to some degree... but nobody can make someone else implement
>> something
>> > they don't want.
>>
>> The last patch is from the 6th of December and does not apply anymore:
>> https://www.postgresql.org/message-id/CAFj8pRA9w_AujBAYdLR0U
>> VfXwwoxhmn%2BFbNHnD3_NL%3DJ9x3y8w%40mail.gmail.com
>> I don't have a better idea than marking this patch as "returned with
>> feedback" for now, as the thread has died 3 weeks ago as well.
>>
>
> There is not a agreement on the form of session variables.
>

Today I found on net a documentation to DB2 "CREATE VARIABLE" command. I
had not any idea, so this statement exists already, although it is old
feature - I found a doc from 2007.

The DB2 design is very similar to my proposal - secured access, persistent
metadata, unshared untransactional data limmited by session.

They doesn't use a access functions - the access is with notation
schemaname.variablename. I proposed this syntax as next step in
implementation.

The DB2 authors doesn't propose transactional variables - when user needs
XA behave, then global temporary tables should be used.

My patch was marked as "returned with feedback". Personally, I had not a
idea what can be next step and what is preferred design, if some preferred
design exists. I don't know what I have to change on my proposal.

I understand, so there are two different concepts - 1. using variables for
adhoc writing like T-SQL, MySQL or 2. using variables as global session
objects for stored procedures.

The @1 area is partially solved by psql session variables or by pgAdmin
scripting functionality. @2 is partially solved by GUC but without
possibility to set a access rights.

I didn't found any implementation of XA variables or persistent variables
on the world.

Regards

Pavel

>
> Regards
>
> Pavel
>
>
>> --
>> Michael
>>
>
>