maria-discuss team mailing list archive

[Federico Razzoli <federico_raz@xxxxxxxx>]

Hi Roberto
I'll try to be more clear, please read carefully before answering

I know what a deterministic expression is - but what kinds of output must be deterministic for a procedure to be defined as DETERMINISTIC?

There are many types of output for a proc:
* OUT params
* SELECTs
* writes on tables
* SET @var

For a deterministic proc, do all of these need to be deterministic?

I guess the answer isn't easy.

--

For "NO SQL" a complete list of SQL statements would be needed. If we use this as a reference:
http://dev.mysql.com/doc/refman/5.6/en/sql-syntax.html
, even RETURN seems to be a SQL statement, but of course it can't be true, because it's impossible to write a func without RETURN.

Greetings
Federico


--------------------------------------------
Lun 2/9/13, Roberto Spadim <roberto@xxxxxxxxxxxxx> ha scritto:

 Oggetto: Re: [Maria-discuss] CREATE PROCEDURE clauses
 A: "Federico Razzoli" <federico_raz@xxxxxxxx>
 Cc: "Mailing-List mariadb" <maria-discuss@xxxxxxxxxxxxxxxxxxx>
 Data: Lunedì 2 settembre 2013, 15:23
 
 Hi Federico!
 
 
 2013/9/2 Federico Razzoli <federico_raz@xxxxxxxx>:
 > Ciao,
 >
 > I wanted to add some info in the CREATE PROCEDURE page
 in the KB, but I think that some info about CREATE PROCEDURE
 clauses miss both in the kb and in the MySQL manual.
 >
 > * [NOT] DETERMINISTIC. From MySQL docs:
 > "A routine is considered “deterministic” if it
 always produces the same result for the same input
 parameters, and “not deterministic” otherwise."
 > What does this exactly mean for procedures? OUT and
 INOUT parameters? Resultsets returned by the procedure?
 Both?
 
 i think it's something like: RANDON() = not deterministic,
 ROUND(1.5)
 = deterministic
 maybe it's important for replication (must be done via
 binary, instead
 SQL), and it's important for query cache (not deterministic
 can't be
 cached)
 
 
 > * NO SQL: As far as I understand, even SET is a SQL
 statement. I guess that a "no sql" function is something
 like
 > CREATE FUNCTION x(n INT) RETURNS INT
 > BEGIN
 > RETURN n*2;
 > END;
 >
 > But what is a "no sql" procedure (if such a procedure
 even exists)?
 
 i don't know, but reading mysql protocol, there's some
 functions for
 show fields, process info, process kill,
 http://dev.mysql.com/doc/internals/en/text-protocol.html
 
 > I'm sorry if this info is already written somewhere,
 but I really wasn't able to find it - and I feel that the KB
 should specify things like these.
 >
 > Greetings
 > Federico
 >
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 > More help   : https://help.launchpad.net/ListHelp
 
 
 
 -- 
 Roberto Spadim
 SPAEmpresarial