Thank you very much!
It may be because my system's resource is limited. It's a embedded system
containing 32M RAM, ARM9 CPU.
My "reiterating 20 times" is already using usleep().
After I add the loop in the prepare statements, the system performance is
still very bad... And there are still many errores of SQLITE_BUSY.
The only improvement is the disappear of the error of SQLITE_MISUSE.
And I tried to use the "BEGIN EXCLUSIVE TRANSACTION". The things are same
with them without using it.
Black, Michael (IS) wrote:
>
> Your "reiterating 20 times" is not using a usleep so you'll blow by this
> most every time it's busy.
>
> Do this instead in all your proc's
>
> ret = sqlite3_step (p_stmt);
> if (SQLITE_BUSY == ret)
> {
> int n=0;
> usleep(100000); // try one more time before error
> while ((ret=sqlite3_step(p_stmt))==SQLITE_BUSY) {
> printf("proc1 ret==BUSY %d\n",++n);
> usleep(100000);
> }
> }
>
> And you'll also need to handle "database is locked" coming from your
> prepare statements. I saw that error too.
> You'll need to loop there too.
>
> The more you drop the usleep time the more times it will show as busy.
> 1/10th or 1/100th of second is about all you want I would think.
>
> And get rid of the usleep at the bottom of each proc -- it's pretty
> useless at 100 microseconds. You don't need to sleep unless you're busy.
>
> I tested your code with this and got no errors at all -- just a bunch of
> BUSY messages.
>
>
> Not sure what your purpose is in sqlrun.c with looping and killing. Looks
> pretty squirrely to me. You're not waiting for the forks to finish so
> what is your logic here?
>
> Michael D. Black
> Senior Scientist
> Northrop Grumman Mission Systems
>
>
> ________________________________
>
> From: [email protected] on behalf of liubin liu
> Sent: Tue 5/11/2010 4:57 AM
> To: [email protected]
> Subject: [sqlite] multi processes, so many errores of SQLITE_BUSY and
> SQLITE_MISUSE
>
> ...
>
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