[sr-dev] db_fetch_next problem with Postgres?

[Paul Pankhurst]

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, 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

From: Daniel-Constantin Mierla 
Sent: Tuesday, December 13, 2011 12:27 PM
To: Development mailing list of the sip-router project 
Cc: Paul Pankhurst 
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

  From: Paul Pankhurst 
  Sent: Tuesday, December 13, 2011 12:03 PM
  To: miconda at gmail.com 
  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

  From: Daniel-Constantin Mierla 
  Sent: Tuesday, December 13, 2011 11:10 AM
  To: Development mailing list of the sip-router project 
  Cc: Paul Pankhurst 
  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
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