On 09/04/2015 10:13 PM, Domingo Alvarez Duarte wrote:
> Hello again !
>
> I looked at the documentaion again and realized that I was alread calling
> sqlite3_close_v2 the I commented out all of the sqlite3_next_stmt cleanup and
> no segfaults so far, I'll see if memory is released on a long running process
> to certify that everything is fine.
The trouble with sqlite3_close_v2() is that after you call it you can't
safely pass the db handle to sqlite3_next_stmt() - the data structure
may have already been freed.
Dan.
>
> Thanks a lot for your help !
>
>
>
>> Fri Sep 04 2015 4:57:57 pm CEST CEST from "Domingo Alvarez Duarte"
>> <sqlite-mail at dev.dadbiz.es> Subject: Re: [sqlite] SQLite3 trunk error
>> with
>> old database with fts3/4
>>
>> Hello !
>>
>> I did something similar to your sugestion (sqlite3_next_stmt(db, NULL))
>> and
>> it still segfaults.
>>
>> What you mention about fts3/4 having prepared statemtns that and somehow
>> I'm
>> doing a double free a good point.
>>
>> And will be sad to not be able to use sqlite3_next_stmt(db, NULL) to
>> finalize
>> any open preapred statemnt, because it's very handy when using "exceptions"
>> and having a single point to do the cleanup.
>>
>> Can somehow sqlite3_prepare somehow have any extra parameter to indicated
>> that we are using it from an extension and somehow sqlite3_next_stmt detect
>> it and skip it ?
>>
>> Or any way to safely have a central point to do a cleanup ?
>>
>> Cheers !
>>
>>
>>> Fri Sep 04 2015 4:44:02 pm CEST CEST from "Dan Kennedy"
>>> <danielk1977 at gmail.com> Subject: Re: [sqlite] SQLite3 trunk error with
>>> old
>>> database with fts3/4
>>>
>>> On 09/04/2015 09:29 PM, Domingo Alvarez Duarte wrote:
>>>
>>>
>>>> Hello again !
>>>>
>>>> On mac os x some time ago I was getting segfaults here and tought that it
>>>> was
>>>> caused by the way os x manage memory but it doesn't seem correct.
>>>>
>>>> The error happens on this code that is called before call sqlite3_close:
>>>>
>>>> sqlite3 *db = sdb->db;
>>>> sqlite3_stmt* statement = NULL;
>>>> int count = 0;
>>>> while ((statement = sqlite3_next_stmt(db, statement)))
>>>> {
>>>> //do no close statements because garbage collector will
>>>> do it
>>>> //on MacOSX we get segfaults finalizing statements here
>>>> printf("sq_sqlite3_close_release:stmt:%s\n",
>>>> sqlite3_sql(statement));
>>>> sqlite3_finalize(statement);
>>>> count++;
>>>> }
>>>> if (count) return sq_throwerror(v, _SC("closing database with
>>>> %d statements not closed."), count);
>>>>
>>>>
>>> Hi,
>>>
>>> Two problems:
>>>
>>> After you have finalized a statement handle, it may not be passed to
>>> sqlite3_next_stmt(). Change the while() line to:
>>>
>>> while( (statement = sqlite3_next_stmt(db, NULL)) ){ ...
>>>
>>> Another reason not to do this before calling sqlite3_close() is that the
>>> FTS module may be managing some of these statement handles. So if you
>>> finalize() them before sqlite3_close() is called, then when the FTS
>>> module is shut down as part of the eventual sqlite3_close() call, it may
>>> pass the same statement handle pointers to sqlite3_finalize() - similar
>>> to a double-free of any other object or memory allocation. SQLite
>>> includes checks to try to return SQLITE_MISUSE instead of crashing when
>>> this happens, but they only work some of the time - this scenario can
>>> still cause crashes or heap corruption.
>>>
>>> A workaround is to call sqlite3_close() on the db, then do the above
>>> only if it returns SQLITE_BUSY. This works because, even though it
>>> fails, the first sqlite3_close() shuts down the FTS module -
>>> guaranteeing that it is no longer holding pointers to statement handles.
>>>
>>> Even better is not to leak statement handle pointers. The
>>> sqlite3_next_stmt() API should really only be used to help track down
>>> leaks, not to do cleanup.
>>>
>>> Dan.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>>
>>>>> Fri Sep 04 2015 4:18:01 pm CEST CEST from "Domingo Alvarez Duarte"
>>>>> <sqlite-mail at dev.dadbiz.es> Subject: Re: [sqlite] SQLite3 trunk error
>>>>> with
>>>>> old database with fts3/4
>>>>>
>>>>> Hello !
>>>>>
>>>>> I'm not sure where the problem is but this code worked without any
>>>>> problem
>>>>> with previous sqlite3.
>>>>>
>>>>> Here is a backtrace of a segfault using gdb (the line numbers will not
>>>>> match
>>>>> standard sqlite3.c because I have some custom extensions):
>>>>>
>>>>> enter mutex 0x7fffe405f570 (1213663847) with nRef=1919906927
>>>>>
>>>>> Program received signal SIGSEGV, Segmentation fault.
>>>>> [Switching to Thread 0x7ffff3c70700 (LWP 22336)]
>>>>> 0x0000000000479d85 in freeEphemeralFunction (db=0x7fffe4000078,
>>>>> pDef=0xaaaaaaaaaaaaaaaa)
>>>>> at sqlite3.c:66869
>>>>> 66869 if( ALWAYS(pDef) && (pDef->funcFlags & SQLITE_FUNC_EPHEM)!=0
>>>>> ){
>>>>> (gdb) bt
>>>>> #0 0x0000000000479d85 in freeEphemeralFunction (db=0x7fffe4000078,
>>>>> pDef=0xaaaaaaaaaaaaaaaa)
>>>>> at sqlite3.c:66869
>>>>> #1 0x0000000000479e39 in freeP4 (db=db at entry=0x7fffe4000078,
>>>>> p4type=-1431655766, p4=0x7fffe4181588)
>>>>> at sqlite3.c:66884
>>>>> #2 0x0000000000479f14 in vdbeFreeOpArray (db=0x7fffe4000078,
>>>>> aOp=0x7fffe40df508, nOp=<optimised out>)
>>>>> at sqlite3.c:66933
>>>>> #3 0x000000000047a01c in sqlite3VdbeClearObject (db=0x7fffe4000078,
>>>>> p=0x7fffe408ac88) at sqlite3.c:68920
>>>>> #4 0x000000000047a0c3 in sqlite3VdbeDelete (p=0x7fffe408ac88)
>>>>> at sqlite3.c:68941
>>>>> #5 0x00000000004e6044 in sqlite3VdbeFinalize (p=0x7fffe408ac88)
>>>>> at sqlite3.c:68861
>>>>> #6 0x00000000004e60cd in sqlite3_finalize (pStmt=0x7fffe408ac88)
>>>>> at sqlite3.c:70500
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Fri Sep 04 2015 4:05:12 pm CEST CEST from "Dan Kennedy"
>>>>>> <danielk1977 at gmail.com> Subject: Re: [sqlite] SQLite3 trunk error with
>>>>>> old
>>>>>> database with fts3/4
>>>>>>
>>>>>> On 09/04/2015 07:35 PM, Domingo Alvarez Duarte wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Hello !
>>>>>>>
>>>>>>> After fix the index issues using an old sqlite3 executable (the trunk
>>>>>>> refuse
>>>>>>> to work on indexes created with single quotes on field names) I'm
>>>>>>> getting
>>>>>>> ocasionaly memory errors when using fts3/4 searches, see error below:
>>>>>>>
>>>>>>> free(): corrupted unsorted chunks: 0x00007fa3a01073a0
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> Is this error on the trunk or with the old version?
>>>>>>
>>>>>> If it's on the trunk, is the error reproducible using the sqlite3 shell
>>>>>> tool?
>>>>>>
>>>>>> If not, what does valgrind have to say about the app?
>>>>>>
>>>>>> Thanks,
>>>>>> Dan.
>>>>>>
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>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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