[GENERAL] Threads With Libpq Issue

[dinesh kumar]

Respected All,

This is my first post in PG-Generals. If it is not the place for these kind
of queries, then please guide me where i need to post.

I have a quick question regarding "pthread" with PostgreSQL 9.0 Libpq. I'm
facing a problem with "Pthread" and libpq. Please find the below program
behavoiur.

Connection_To_PG()
{
/* Making a connection to PG 9.0 */
}

void* Independent_Thread1()
{
while(1)
{
sleep(5);
/* Doing 1 Insert Operation on Table A*/
}
}

void* Independent_Thread2()
{
while(1)
{
sleep(5);
/*Doing 1 Insert Operation on Table B*/
}

main()
{
pthread Ind1,Ind2;
Connection_TO_PG();
pthread_create(&Ind1,NULL,&Independent_Thread1,NULL);
pthread_create(&Ind2,NULL,&Independent_Thread2,NULL);
if(pthread_join(Ind1,NULL)<0)
{
printf("Ind1 is completed");
}
if(pthread_join(Ind2,NULL)<0)
{
printf("Ind2 is completed");
}
}


Problem Description:
====================
When i ran the above program, it's running(i.e inserting 2 to 10 records)
some time and going to hang state. Some times, it's running more than 15
minutes and some times only 2 to 3 minutes. I enabled the postgresql log
level to DEBUG5, and it's also stopped to showing the progress after 2 to 3
minutes span of time.

Can some advise me, where i'm doing mistake in the above source code.. And
would like to know to why it's not functioning properlly .. And i'm also
getting the following message when the above libpq program runs..

************* Message **************************
message type 0x31 arrived from server while idle
message type 0x32 arrived from server while idle
message type 0x6e arrived from server while idle
message type 0x43 arrived from server while idle
message type 0x5a arrived from server while idle

However, the below sample thread(i.e without libpq) programg is working
fine witout any issues.

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>

void* thread1()
{
        while(1){
                printf("Thread1\n");
        }
}

void* thread2()
{
        while(1){
                printf("Thread2\n");
        }
}

int main()
{
        int status;
        pthread_t tid1,tid2;
        pthread_create(&tid1,NULL,&thread1,NULL);
        pthread_create(&tid2,NULL,&thread2,NULL);
        pthread_join(tid1,NULL);
        pthread_join(tid2,NULL);
        return 0;
}


Thanks in advance ...

Best Regards,
Dinesh
manojadinesh.blogspot.com