Re: Thread safe connection-name mapping in ECPG. Is it - Mailing list pgsql-hackers

Oh.. By all means..Please do..

The reason I posted it because I didn't wanted to work on it if core is not 
going to accept it on account of non-compliance with spec.

Is this fine? * Allow a 'connection *' pointer to be specified instead of a string to denote 
a connection.

I plan to work on it whenever possible. What I would like to do is eliminate the 
locks around name->connection mapping as we would be directly using the 
connection instead of a name.

I think we can also add the SQL-CA to connection structure so that each 
connection gets it's  own SQL-CA. That way ECPG is as thread-safe as the calling 
application gets.

And on the plus side we don't have to worry about platform specific threading 
models either.

Thoughts?
 Shridhar

Bruce Momjian wrote:

> Should I add this to the TODO list?
> 
> ---------------------------------------------------------------------------
> 
> Lee Kindness wrote:
> 
>>Sort of related, I was thinking about adding some more thread-related
>>code such that if a connection wasn't explicitely specified then the
>>last connection SET or CONNECTed to for the current thread is used,
>>rather than just the "last connection".
>>
>>But yeah, specifying the connection by variable (be it string or
>>connection ptr) would be a definite step forward. Currently you cannot
>>write a generic function like:
>>
>> int getit(char *using_connection)
>> {
>>  EXEC SQL BEGIN DECLARE SECTION;
>>  char *s_connection = using_connection;
>>  int s_it;
>>  EXEC SQL END DECLARE SECTION;
>>
>>  EXEC SQL AT :s_connection SELECT it INTO :s_it FROM some_table;
>>  return( s_it );
>> }
>>
>>which could be run concurrently by multiple threads.
>>
>>L.
>>
>>Shridhar Daithankar writes:
>> > On Friday 27 February 2004 20:54, Michael Meskes wrote:
>> > > On Fri, Feb 27, 2004 at 04:22:33PM +0530, Shridhar Daithankar wrote:
>> > > > How about, allowing 'connection *'? If somebody puts a 'connection *'
>> > > > there it is used. If it is a string a name search is performed. Best of
>> > > > both worlds.
>> > >
>> > > How shall anyone put a pointer to a connection struct inside the SQL
>> > > statement?
>> > >
>> > > It would help me a lot if you'd be able to give some examples.
>> > 
>> > EXEC SQL BEGIN DECLARE SECTION;
>> >  connect *connectionPtr;
>> > EXEC SQL END DECLARE SECTION;
>> > 
>> > EXEC SQL CONNECT TO db AS connectionPtr;
>> > EXEC SQL AT connectionPtr SELECT 1;
>> > 
>> > After all, it is matter of parsing some code and emitting equivalent C code, 
>> > isn't it?
>> > 
>> >  Shridhar
>>
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> 
>