Re: [sqlite] Deadlock with two local instances

[Marcus Grimm]

> On Tue, 27 Oct 2009 21:50:12 +0100, "Marcus Grimm"
>  wrote:
>
>>PS: Does anybody know how I can edit this
>>example code ? I recently attempted to add a clear
>>PD statement and also add some comments but when
>>I try to edit I allways end up in the wiki index page...
>
> Last time I edited the wiki, it went like this:
>
> You're looking at a page you want to edit.
> Press edit button, the mathematical skill testing question
> page pops up, follow directions to login.
> Indeed, now the wiki returns to its start page.
> Navigate to the page you want to edit again, now you can
> press the edit button again and start editing.

uhh... yes! that did the trick! :-)
Thanks!

Marcus

> --
>   (  Kees Nuyt
>   )
> c[_]
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>


___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] Deadlock with two local instances

[Kees Nuyt]

On Tue, 27 Oct 2009 21:50:12 +0100, "Marcus Grimm"
 wrote:

>PS: Does anybody know how I can edit this
>example code ? I recently attempted to add a clear
>PD statement and also add some comments but when
>I try to edit I allways end up in the wiki index page...

Last time I edited the wiki, it went like this:

You're looking at a page you want to edit.
Press edit button, the mathematical skill testing question
page pops up, follow directions to login.
Indeed, now the wiki returns to its start page.
Navigate to the page you want to edit again, now you can
press the edit button again and start editing.
-- 
  (  Kees Nuyt
  )
c[_]
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] Deadlock with two local instances

[Marcus Grimm]

> Thanks!  I ran the example code and it seems like every UPDATE fails
> with errors like the following:
>
> SqlStep Timeout on handle: 8 (rc = 6)
> SqlStep tries on handle 8: 200
> BeginTrans Timeout/Error on handle:  8, Errorcode = 6
> Write Thread: DB is busy! tries = 142 handle = 8
>
> Looking at the database contents it looks like none of the updates
> were successful at all (though I didn't look extremely carefully).
>
> Are these errors normal?

A moderate number of timeout messages is "normal", they where
also added to understand better how much load the sqlite db
can handle using a multi thread application.

However, this example was running with allmost no final error messages
like "DB is busy! tries = 142", at least when I did it some month
ago. The 142 tries means that the DB was busy for more than 1420 sec.
I can't remeber that I achieved this, at least not with only two
writer threads.

You may reduce the number of writer threads by one using:

#define NUM_WRITE_THREADS  1

If that still gives you an endless number of the above
timeout messages then something is definetly wrong in your
system.

Please be aware also of:

a) This exe is assumed to be the only instance running
   on a system.

b) I'm still confident that the loop-redo style of
   the busy handling is one way to do it but the
   sqlite developers included a more clever approach
   using an notifier to handle this:
   http://www.sqlite.org/unlock_notify.html
   Havent tried this, though.

c) Maybe a virus scanner is interfering here ?

d) Maybe your system is slow ? :-)

Marcus

PS: Does anybody know how I can edit this
example code ? I recently attempted to add a clear
PD statement and also add some comments but when
I try to edit I allways end up in the wiki index page...

>
> On Tue, Oct 27, 2009 at 12:55 AM, Marcus Grimm 
> wrote:
>>> Another odd thing is that when I call sqlite3_reset on the prepared
>>> statement, it also returns SQLITE_BUSY.  Should I only reset the
>>> statement when it has been executed successfully?
>>
>> one possible approach when getting SQLITE_BUSY is to
>> retry the sqlite3_step call until it finally gets thru.
>>
>> note that sqlite3_reset just returns the same error
>> code as the previous sqlite3_step call.
>>
>> attachments don't work on the list, you will need
>> find another way to provide your example code.
>>
>> you may also take a look at
>> http://www.sqlite.org/cvstrac/wiki?p=SampleCode
>> for the busy handling.
>>
>> hth
>>
>> Marcus Grimm
>>
>>>
>>> On Mon, Oct 26, 2009 at 2:40 PM, Chris T  wrote:
 I'm new to sqlite (and sql in general, actually) and came across
 something puzzling.

 I wrote a test program statically linked with the amalgamated sqlite
 code.  When I run a single instance, everything is fine.  When I start
 a second instance in the same directory they both deadlock.  Every
 call to sqlite3_step returns SQLITE_BUSY.

 The source code to my test program is attached.  It was written in
 Visual Studio, so feel free to remove the reference to windows.h and
 change the calls to Sleep( ) if you don't use Windows.

>>> ___
>>> sqlite-users mailing list
>>> sqlite-users@sqlite.org
>>> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>>>
>>
>>
>> ___
>> sqlite-users mailing list
>> sqlite-users@sqlite.org
>> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>>
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>


___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] Deadlock with two local instances

[Pavel Ivanov]

> Are these errors normal?

If you're executing select statement, never get all rows from it and
never reset/finalize it then yes, all updates from other thread will
fail and it's normal.

Pavel

On Tue, Oct 27, 2009 at 1:42 PM, Chris T  wrote:
> Thanks!  I ran the example code and it seems like every UPDATE fails
> with errors like the following:
>
> SqlStep Timeout on handle: 8 (rc = 6)
> SqlStep tries on handle 8: 200
> BeginTrans Timeout/Error on handle:  8, Errorcode = 6
> Write Thread: DB is busy! tries = 142 handle = 8
>
> Looking at the database contents it looks like none of the updates
> were successful at all (though I didn't look extremely carefully).
>
> Are these errors normal?
>
> On Tue, Oct 27, 2009 at 12:55 AM, Marcus Grimm  
> wrote:
>>> Another odd thing is that when I call sqlite3_reset on the prepared
>>> statement, it also returns SQLITE_BUSY.  Should I only reset the
>>> statement when it has been executed successfully?
>>
>> one possible approach when getting SQLITE_BUSY is to
>> retry the sqlite3_step call until it finally gets thru.
>>
>> note that sqlite3_reset just returns the same error
>> code as the previous sqlite3_step call.
>>
>> attachments don't work on the list, you will need
>> find another way to provide your example code.
>>
>> you may also take a look at http://www.sqlite.org/cvstrac/wiki?p=SampleCode
>> for the busy handling.
>>
>> hth
>>
>> Marcus Grimm
>>
>>>
>>> On Mon, Oct 26, 2009 at 2:40 PM, Chris T  wrote:
 I'm new to sqlite (and sql in general, actually) and came across
 something puzzling.

 I wrote a test program statically linked with the amalgamated sqlite
 code.  When I run a single instance, everything is fine.  When I start
 a second instance in the same directory they both deadlock.  Every
 call to sqlite3_step returns SQLITE_BUSY.

 The source code to my test program is attached.  It was written in
 Visual Studio, so feel free to remove the reference to windows.h and
 change the calls to Sleep( ) if you don't use Windows.

>>> ___
>>> sqlite-users mailing list
>>> sqlite-users@sqlite.org
>>> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>>>
>>
>>
>> ___
>> sqlite-users mailing list
>> sqlite-users@sqlite.org
>> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>>
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] Deadlock with two local instances

[Chris T]

Thanks!  I ran the example code and it seems like every UPDATE fails
with errors like the following:

SqlStep Timeout on handle: 8 (rc = 6)
SqlStep tries on handle 8: 200
BeginTrans Timeout/Error on handle:  8, Errorcode = 6
Write Thread: DB is busy! tries = 142 handle = 8

Looking at the database contents it looks like none of the updates
were successful at all (though I didn't look extremely carefully).

Are these errors normal?

On Tue, Oct 27, 2009 at 12:55 AM, Marcus Grimm  wrote:
>> Another odd thing is that when I call sqlite3_reset on the prepared
>> statement, it also returns SQLITE_BUSY.  Should I only reset the
>> statement when it has been executed successfully?
>
> one possible approach when getting SQLITE_BUSY is to
> retry the sqlite3_step call until it finally gets thru.
>
> note that sqlite3_reset just returns the same error
> code as the previous sqlite3_step call.
>
> attachments don't work on the list, you will need
> find another way to provide your example code.
>
> you may also take a look at http://www.sqlite.org/cvstrac/wiki?p=SampleCode
> for the busy handling.
>
> hth
>
> Marcus Grimm
>
>>
>> On Mon, Oct 26, 2009 at 2:40 PM, Chris T  wrote:
>>> I'm new to sqlite (and sql in general, actually) and came across
>>> something puzzling.
>>>
>>> I wrote a test program statically linked with the amalgamated sqlite
>>> code.  When I run a single instance, everything is fine.  When I start
>>> a second instance in the same directory they both deadlock.  Every
>>> call to sqlite3_step returns SQLITE_BUSY.
>>>
>>> The source code to my test program is attached.  It was written in
>>> Visual Studio, so feel free to remove the reference to windows.h and
>>> change the calls to Sleep( ) if you don't use Windows.
>>>
>> ___
>> sqlite-users mailing list
>> sqlite-users@sqlite.org
>> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>>
>
>
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] Deadlock with two local instances

[Marcus Grimm]

> Another odd thing is that when I call sqlite3_reset on the prepared
> statement, it also returns SQLITE_BUSY.  Should I only reset the
> statement when it has been executed successfully?

one possible approach when getting SQLITE_BUSY is to
retry the sqlite3_step call until it finally gets thru.

note that sqlite3_reset just returns the same error
code as the previous sqlite3_step call.

attachments don't work on the list, you will need
find another way to provide your example code.

you may also take a look at http://www.sqlite.org/cvstrac/wiki?p=SampleCode
for the busy handling.

hth

Marcus Grimm

>
> On Mon, Oct 26, 2009 at 2:40 PM, Chris T  wrote:
>> I'm new to sqlite (and sql in general, actually) and came across
>> something puzzling.
>>
>> I wrote a test program statically linked with the amalgamated sqlite
>> code.  When I run a single instance, everything is fine.  When I start
>> a second instance in the same directory they both deadlock.  Every
>> call to sqlite3_step returns SQLITE_BUSY.
>>
>> The source code to my test program is attached.  It was written in
>> Visual Studio, so feel free to remove the reference to windows.h and
>> change the calls to Sleep( ) if you don't use Windows.
>>
> ___
> sqlite-users mailing list
> sqlite-users@sqlite.org
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>


___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Re: [sqlite] Deadlock with two local instances

[Chris T]

Another odd thing is that when I call sqlite3_reset on the prepared
statement, it also returns SQLITE_BUSY.  Should I only reset the
statement when it has been executed successfully?

On Mon, Oct 26, 2009 at 2:40 PM, Chris T  wrote:
> I'm new to sqlite (and sql in general, actually) and came across
> something puzzling.
>
> I wrote a test program statically linked with the amalgamated sqlite
> code.  When I run a single instance, everything is fine.  When I start
> a second instance in the same directory they both deadlock.  Every
> call to sqlite3_step returns SQLITE_BUSY.
>
> The source code to my test program is attached.  It was written in
> Visual Studio, so feel free to remove the reference to windows.h and
> change the calls to Sleep( ) if you don't use Windows.
>
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

[sqlite] Deadlock with two local instances

[Chris T]

I'm new to sqlite (and sql in general, actually) and came across
something puzzling.

I wrote a test program statically linked with the amalgamated sqlite
code.  When I run a single instance, everything is fine.  When I start
a second instance in the same directory they both deadlock.  Every
call to sqlite3_step returns SQLITE_BUSY.

The source code to my test program is attached.  It was written in
Visual Studio, so feel free to remove the reference to windows.h and
change the calls to Sleep( ) if you don't use Windows.
___
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users