I see many SQLITE_BUSY returned from sqlite3_finalize(). Are they memory leak
because it don't succeed in finalizing the sqlite3_stmt pointer?
Black, Michael (IS) wrote:
>
> SQLITE_BUSY is not an error...just a fact.
>
> All your processes cannot work on the database at the same time...at least
> not when one of them is doing an insert. You could be changing the table
> while you're scanning it. EXXCLUSIVE doesn't change that idea.
>
> Somebody please correct me if I'm wrong on this one...
> I think sqlite can work with multiple processes just doing read-onliy
> operations (like SELECT). It's just the write operations
> (INSERT/UPDATE) which will cause SQLITE_BUSY to occur.
>
> Michael D. Black
> Senior Scientist
> Northrop Grumman Mission Systems
>
>
> ________________________________
>
> From: sqlite-users-boun...@sqlite.org on behalf of liubin liu
> Sent: Tue 5/11/2010 9:20 PM
> To: sqlite-users@sqlite.org
> Subject: Re: [sqlite] multi processes, so many errores of SQLITE_BUSY and
> SQLITE_MISUSE
>
>
>
>
> 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: sqlite-users-boun...@sqlite.org on behalf of liubin liu
>> Sent: Tue 5/11/2010 4:57 AM
>> To: sqlite-users@sqlite.org
>> Subject: [sqlite] multi processes, so many errores of SQLITE_BUSY and
>> SQLITE_MISUSE
>>
>> ...
>>
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