> How to rollback current transaction?
Execute statement "ROLLBACK".
Pavel
On Fri, May 14, 2010 at 2:20 AM, liubin liu <7101...@sina.com> wrote:
>
> How to rollback current transaction?
>
>
>
>
>
> Pavel Ivanov-2 wrote:
>>
>>> I assume you want the sqllite3_stmt to work -- so you need to loop that
>>> while it's busy.
>>
>> Michael, don't give bad advices.
>> The most general advice when one gets SQLITE_BUSY is to reset/finalize
>> all statements and rollback current transaction. It's only in certain
>> type of transactions and certain type of statements one can loop while
>> sqlite3_stmt returns SQLITE_BUSY. But even in this case one must call
>> sqlite3_reset on the statement that returned SQLITE_BUSY. And this
>> call to sqlite3_reset will return SQLITE_BUSY again.
>>
>>
>> Pavel
>>
>> On Thu, May 13, 2010 at 7:20 AM, Black, Michael (IS)
>> <michael.bla...@ngc.com> wrote:
>>> It also means you're not handling the SQLITE_BUSY from the sqlite3_stmt()
>>> before it.
>>> I assume you want the sqllite3_stmt to work -- so you need to loop that
>>> while it's busy.
>>>
>>> Michael D. Black
>>> Senior Scientist
>>> Northrop Grumman Mission Systems
>>>
>>>
>>> ________________________________
>>>
>>> From: sqlite-users-boun...@sqlite.org on behalf of liubin liu
>>> Sent: Thu 5/13/2010 2:07 AM
>>> To: sqlite-users@sqlite.org
>>> Subject: Re: [sqlite] multi processes, so many errores of SQLITE_BUSY and
>>> SQLITE_MISUSE
>>>
>>>
>>>
>>>
>>> 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
>>>>>
>>>>> ...
>>>>>
>>>>> --
>>>>> View this message in context:
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>>>>> Sent from the SQLite mailing list archive at Nabble.com.
>>>>>
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>>>>>
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>>>>
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