I don't know if it will actually cause problems, but is the
"?command.Dispose()" needed? Doesn't the "using" handle disposing?
Graham
Sent from Samsung Mobile
-------- Original message --------
From: Artem <devs...@yandex.ru>
Date: 28/04/2015 14:29 (GMT+00:00)
To: General Discussion of SQLite Database <sqlite-users at
mailinglists.sqlite.org>
Subject: Re: [sqlite] Segfault during FTS index creation from huge data
No, I'm sure that is not a problem in my software, it exactly
error of the SQLite library. My software is very simple - it creates
simple connection to the database with connection string like
"Data Source={0};New=false;Journal Mode=Off;Synchronous=Off;FailIfMissing=True"
and executes a query like
INSERT INTO test_fts(test_fts) VALUES('rebuild');
and that is all.
I'm pretty sure because I got exactly the same error in SQLite Expert
Professional -
popular? desktop? sqlite-management? software, that uses another
sqlite driver.
P.S. Source code of my function:
Using conn As New SQLiteConnection(String.Format("Data
Source={0};New=false;Journal Mode=Off;Synchronous=Off;FailIfMissing=True",
"f:\Suggests\suggests.db"))
??? conn.Open()
??? Using command = conn.CreateCommand
??????? command.CommandText = "INSERT INTO suggests_fts(suggests_fts)
VALUES('rebuild');"
??????? command.ExecuteNonQuery()
??????? command.Dispose()
??? End Using
??? conn.Close()
End Using
P.S. I can send the database to someone who can try, 19 GB in
rar-archive.
> Getting "NoMem" sounds very much like a memory leak somewhere, with
> the most likely place being your own application, followed by the
> wrapper you are using, the FTS code and lastly the SQLite core.
> Lastly because the SQLite core is extensively tested with an
> explicit emphasis on not leaking memory (or other resources) in the
> first place and secondly recovering gracefully from memory allocation
> failures.
> Also, since you have swapped out SQLite versions and even operating
> systems without eliminating the problem, it seems rational to look
> into the parts that have remained the same.
> Maybe you could run a test on Linux under the control of valgrind
> and have its memcheck tool take a look.
> -----Urspr?ngliche Nachricht-----
> Von: Artem [mailto:devspec at yandex.ru]
> Gesendet: Dienstag, 28. April 2015 14:36
> An: General Discussion of SQLite Database
> Betreff: Re: [sqlite] Segfault during FTS index creation from huge data
>> On 04/03/2015 10:16 PM, Artem wrote:
>>> Hi!
>>>
>>> The situation is like that. There?s a SQLite database with around 3 billion
>>> records. Each record consists of a certain CHAR field and several other
>>> additional fields with different types. The file size is approx. 340 gb.
>>> The maximum content length in the doc field is 256 symbols, the content is
>>> in Russian.
>>>
>>> I?m trying to create a full-text index, but it results in a Segmentation
>>> Fault error. I?ve been trying to create it in different possible ways, both
>>> under Windows (with SQLite Expert and my own .NET software, including one
>>> with x64 architecture) and Linux (both Ubuntu and Centos). I?ve even
>>> compiled sqlite from the sources, having included necessary flags for FTS3
>>> and FTS4, but every time I get one and the same error.
>> This does sound like a real problem, but one that might be difficult
>> to track down.
>> Are you able to get us a stack trace of the crash? Ideally one from a
>> build with compiler options "-g -DSQLITE_DEBUG" set.
>> Thanks,
>> Dan.
> Hi, Dan. Now I can't to do this because I haven't Linux on my PC.
> But I tried to create FTS table again (now it was another database with
> 1 350 000 000 rows, smaller than before). And I got the same error (out of
> memory) on function:
> internal override SQLiteErrorCode Reset(SQLiteStatement stmt)
> in file SQLite3.cs
> It returns System.Data.SQLite.SQLiteErrorCode.NoMem.
> I home it helps.
> P.S.? It? is? latest? version? of SQLite.Net compiled in Visual Studio 2012.
>>>
>>> I?ve tried two options:
>>> - creating a contentless FTS4, when content is stored in a regular
>>> table, and FTS-table contains only index (create virtual table
>>> docs_fts using fts4(content='docs'... )
>>> - creating a full-fledged FTS table from a regular one (insert into
>>> docs_fts select doc... from docs;)
>>>
>>> SQLite is functioning for about 4 hours, after which Segmentation Fault
>>> error occurs inevitably.
>>> There?re no NULL fields in the database.
>>>
>>> I?ve worked with 3 different SQLite versions, including the latest one,
>>> available on the website. I started trying to create the full-text index of
>>> the base shortly after it was created and filled; no other activity, apart
>>> from filling the base with data, was conveyed. It has only one docs table,
>>> that for sure doesn?t contain any NULL values.
>>> I also had an idea that Reindex and Vacuum might have done something wrong,
>>> however Reindex happens instantly and Vacuum works rather slowly, but
>>> successfully.
>>>
>>> In short, my actions are:
>>>
>>> CREATE TABLE docs ([id] INTEGER PRIMARY KEY AUTOINCREMENT, [doc]
>>> CHAR... (other fields here) (here?s the process of filling the base
>>> with the data, which are downloaded by means of my own script from
>>> text files.)
>>>
>>> CREATE VIRTUAL TABLE docs_fts using fts4 (content='docs', doc...
>>> (other fields here) (here?s an attempt of INSERT INTO
>>> docs_fts(docs_fts) VALUES ('rebuild') to rebuild contentless FTS
>>> index)
>>>
>>> or
>>>
>>> CREATE VIRTUAL TABLE docs_fts using fts4 (doc... (other fields here)
>>> (here?s an attempt of INSERT INTO docs_fts SELECT doc... from docs;)
>>>
>>> or
>>>
>>> CREATE VIRTUAL TABLE docs_fts using fts3 (doc... (other fields here)
>>> (here?s an attempt of INSERT INTO docs_fts SELECT doc... from docs;)
>>>
>>> For each attempt I?ve been making a new copy of the source file, because I
>>> suspected that the base could have got broken after Segmentation Fault. I
>>> even changed the ram-cards, in case if memory was the problem.
>>>
>>> But every time I get one and the same result - Segmentation Fault error.
>>>
>>> So, can you please pay your attention to this problem and fix it ASAP?
>>>
>>> I can send you a file if you need.
>>>
>>> Thank you.
>>>
>>> _______________________________________________
>>> sqlite-users mailing list
>>> sqlite-users at mailinglists.sqlite.org
>>> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
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--
? ?????????,
Artem????????????????????????? mailto:devspec at yandex.ru
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