I have a code change that resolves this issue in a flexible way, before I check it in can anyone see any flaws in it?
 
I decided to allow the first character of the db_url to be set to ‘*’ to indicate that non-pooling is required.
In this way the pooling can be controlled from the config file giving extra flexibility.
I have added a new variable poolid to  db_id struct.
By default this is zero, however in the case that non-pooling is required the poolid is set to a unique value within that pid ensuring the db_id struct is unique and non pooled.
 
Any comments? Good or bad Smile
 
The code changes are fairly minimal and limited to lib/srdb1: db_id.c, db_id.h, db.c
 
Paul
 
Sent: Tuesday, December 13, 2011 3:53 PM
Subject: Re: [sr-dev] db_fetch_next problem with Postgres?
 


On 12/13/11 4:16 PM, Paul Pankhurst wrote:
Thanks for that Daniel.
 
I modified the db_url for 2nd db so it used the actual IP address of my db rather than localhost,
nice idea, indeed -- perhaps can be extended to add some custom hostnames pointing to same in local computer's /etc/hosts, in case one would need more dedicated connection. But it would be better if APi gets extended.

Cheers,
Daniel

hence it didn’t get pooled, and everything magically worked.
 
I think I’ll extend the db api, it doesn’t look too difficult to do.
 
Paul
 
Sent: Tuesday, December 13, 2011 12:27 PM
Subject: Re: [sr-dev] db_fetch_next problem with Postgres?
 
Hello,

On 12/13/11 1:08 PM, Paul Pankhurst wrote:
should have sent this to list – sorry
 
Sent: Tuesday, December 13, 2011 12:03 PM
Subject: Re: [sr-dev] db_fetch_next problem with Postgres?
 
Hi Daniel,
 
I have a bit more information...
 
the outline pseudo code for what I am doing looks like this (removing non relevant stuff)
 
 
db_fetch_query( xcap_db )
 
do
{
 
query( another_2nd_db )
 
} while ( db_fetch_next( xcap_db) )
 
 
it is the query to the second database that breaks everything...if I remove it the problem goes away and db_fetch_next works as expected.
The access to the 2nd database uses completely different db_func_t and db1_cont_t structures to the xcap_db

if it is the same db_url value, then it results in same db1_con_t pointers, since the postgres has connection pool inside and matches an old connection for same db_url when initializing the second one.

Some ideas:
- extend db api with a new function init_new that will always return a new connection -- requires coding in db modules
- make another database where you add a view to the table in initial database and work with it for second connection -- should work without touching kamailio code

Cheers,
Daniel

 
I’ll try running it with extra debug shortly to see if I can see what’s happening
 
Paul
 
Sent: Tuesday, December 13, 2011 11:10 AM
Subject: Re: [sr-dev] db_fetch_next problem with Postgres?
 
Hello,

On 12/13/11 11:40 AM, Paul Pankhurst wrote:
I am having problems with the db_fetch_next routine  and Postgres.
 
I can’t see any problem with my code that calls it, and as far as I can tell the problem appears to be in the db_postgres_fetch_result routine.
On the first invocation of db_postgres_fetch_result  it allocates a result structure and gives me the first 5 rows of the 198 that match my query after calling db_postgres_convert_rows.
On the 2nd invocation it fails to retrieve the next 5 rows because CON_RESULT(_con) is NULL !
Anyone got any suggestions?
can you doublecheck and see if you don't call free_result() before fetching the next rows? If you run with debug=3, if there is a free_result, you should see the log message from:

LM_DBG("PQclear(%p) result set\n", CON_RESULT(_con))

Cheers,
Daniel
-- 
Daniel-Constantin Mierla -- http://www.asipto.com
http://linkedin.com/in/miconda -- http://twitter.com/miconda


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Daniel-Constantin Mierla -- http://www.asipto.com
http://linkedin.com/in/miconda -- http://twitter.com/miconda


_______________________________________________
sr-dev mailing list
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-- 
Daniel-Constantin Mierla -- http://www.asipto.com
http://linkedin.com/in/miconda -- http://twitter.com/miconda