Hi Iron Bug, You may want to look at https://git.taler.net/exchange.git/src/exchangedb/plugin_exchangedb_postgres.c for inspiration.
There, we use a
/**
* Thread-local database connection.
* Contains a pointer to `struct GNUNET_PQ_Context` or NULL.
*/
pthread_key_t db_conn_threadlocal;
which is turned into a per-thread DB connection here:
if (pthread_equal (pc->main_self,
pthread_self ()))
session = pc->main_session;
else
session = pthread_getspecific (pc->db_conn_threadlocal);
if (NULL != session)
{
GNUNET_PQ_reconnect_if_down (session->conn);
return session;
}
and here:
if (pthread_equal (pc->main_self,
pthread_self ()))
{
pc->main_session = session;
}
else
{
if (0 != pthread_setspecific (pc->db_conn_threadlocal,
session))
{
GNUNET_break (0);
GNUNET_PQ_disconnect (db_conn);
GNUNET_free (session);
return NULL;
}
}
Using
if (0 != pthread_key_create (&pg->db_conn_threadlocal,
&db_conn_destroy))
{
TALER_LOG_ERROR ("Cannot create pthread key.\n");
GNUNET_free (pg->sql_dir);
GNUNET_free (pg);
return NULL;
}
we clean up the thread-specific connection in db_conn_destroy:
static void
db_conn_destroy (void *cls)
{
struct TALER_EXCHANGEDB_Session *session = cls;
struct GNUNET_PQ_Context *db_conn;
if (NULL == session)
return;
db_conn = session->conn;
session->conn = NULL;
if (NULL != db_conn)
GNUNET_PQ_disconnect (db_conn);
GNUNET_free (session);
}
So by my understanding, this should give you all the pieces you need to
achieve what you asked for.
Happy hacking!
Christian
On 7/12/20 9:11 PM, Iron Bug at gmail.com wrote:
>
> Greetings, everybody.
> I write a little network utility using ibmicrohttpd on Linux and I use MHD
> threads pool for better performance.
> My utility uses DB connections and ideally I'd like to have one connection
> instance per thread to avoid unnecessary locks.
> I can use pthreads means (like pthread_key_create) for local thread storage,
> but how can I determine when the thread is created and joined? Is there any
> events or callbacks at every worker thread's start and end where I could hook
> on to open and close my DB connections?
>
> Thanks in advance.
> Yana A. Kireyonok aka Iron Bug
>
0x939E6BE1E29FC3CC.asc
Description: application/pgp-keys
signature.asc
Description: OpenPGP digital signature
