Re: BUG #1569: Threads don't see ecpg default connection - Mailing list pgsql-bugs

Are you still seeing a failure in ecpg?  I ran your test here and got:

    got id = 0
    got id = 0
    got id = 0
    got id = 0
    got id = 0

This is with thread safety enabled and CVS HEAD, which matches 8.0.X.

---------------------------------------------------------------------------

Gavin Scott wrote:
>
> The following bug has been logged online:
>
> Bug reference:      1569
> Logged by:          Gavin Scott
> Email address:      gavin@ipalsoftware.com
> PostgreSQL version: 8.0.1
> Operating system:   Fedora Core 3
> Description:        Threads don't see ecpg default connection
> Details:
>
> When using postgresql 8.0 compiled with --enable-thread-safety, new threads
> no longer see the default ecpg connection.  That was not the case in 7.4.x
> compiled with or without --enable-thread-safety.
>
> TEST CASE
>
> The program at the end of this mail sets up a database table named
> "dbthreadtest" in the default database.  It then spawns 5 threads which each
> do a select from that table using the default connection.
>
> If the program is saved as dbthreadtest.pgc, compile with:
>
> ecpg -t -o dbthreadtest.c dbthreadtest.pgc
> gcc -Wall -o dbthreadtest dbthreadtest.c -lecpg -lpthread
>
> Results under 7.4.x / 8.0 without --enable-thread-safety:
>
> [gavin@hesse protocol_lib]$ psql --version
> psql (PostgreSQL) 7.4.7
> contains support for command-line editing
> [gavin@hesse protocol_lib]$ ./dbthreadtest
> got id = 1
> got id = 1
> got id = 1
> got id = 1
> got id = 1
>
> Results under 8.0 with --enable-thread-safety:
>
> [gavin@marquez protocol_lib]$ psql --version
> psql (PostgreSQL) 8.0.1
> contains support for command-line editing
> [gavin@marquez protocol_lib]$ ./dbthreadtest
> 'No such connection NULL in line 76.', sqlcode = -220 select id
>
> TEST PROGRAM
>
> /* -*-C-*- */
>
> #include <stdlib.h>
> #include <pthread.h>
>
> #define CHECK_SQL(fmt, args...)                \
> do                            \
> {                            \
>   if (sqlca.sqlcode != ECPG_NO_ERROR)            \
>     {                            \
>       fprintf (stderr, "'%s', sqlcode = %ld " fmt "\n",    \
>            sqlca.sqlerrm.sqlerrmc,            \
>            sqlca.sqlcode, ## args);            \
>       exit (1);                        \
>     }                            \
>  }                            \
> while (0)
>
> #define FATAL(fmt, args...)            \
> do                        \
> {                        \
>   fprintf (stderr, fmt "\n", ## args);        \
>   exit (1);                    \
> }                        \
> while (0)
>
> pthread_mutex_t global_lock;
> pthread_t global_threads[5];
>
> void
> setup_db ()
> {
>   exec sql begin declare section;
>     const char *_user;
>   exec sql end declare section;
>
>   pthread_mutex_lock (&global_lock);
>
>   _user = getenv ("LOGNAME");
>
>   exec sql connect to :_user;
>   CHECK_SQL ("connect");
>
>   exec sql create table dbthreadtest (id int);
>   CHECK_SQL ("create dbthreadtest");
>
>   exec sql insert into dbthreadtest (id) values (1);
>   CHECK_SQL ("insert 1");
>
>   pthread_mutex_unlock (&global_lock);
> }
>
> void
> teardown_db ()
> {
>   pthread_mutex_lock (&global_lock);
>
>   exec sql drop table dbthreadtest;
>   CHECK_SQL ("drop dbthreadtest");
>
>   exec sql disconnect;
>   CHECK_SQL ("disconnect");
>
>   pthread_mutex_unlock (&global_lock);
> }
>
> void *query_db (void *ignorep)
> {
>   exec sql begin declare section;
>     int _id;
>   exec sql end declare section;
>
>   pthread_mutex_lock (&global_lock);
>   exec sql select id into :_id from dbthreadtest;
>   CHECK_SQL ("select id");
>
>   fprintf (stdout, "got id = %d\n", _id);
>   pthread_mutex_unlock (&global_lock);
>
>   return NULL;
> }
>
> int
> main ()
> {
>   int i;
>
>   pthread_mutex_init (&global_lock, NULL);
>
>   setup_db ();
>
>   for (i = 0; i < sizeof (global_threads) / sizeof (global_threads[0]);
> ++i)
>     {
>       if (pthread_create (&global_threads[i], NULL, query_db, NULL))
>     FATAL ("pthread_create %d failed", i);
>     }
>
>   for (i = 0; i < sizeof (global_threads) / sizeof (global_threads[0]);
> ++i)
>     {
>       if (pthread_join (global_threads[i], NULL))
>     FATAL ("pthread_join %d failed", i);
>     }
>
>   teardown_db ();
>
>   return 0;
> }
>
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