[sqlite] Problems with pragma journal_mode

[Janke, Julian]

My xFileControl() method has actually returned a SQLITE_OK and not as stated in 
the documentation, a SQLITE_NOTFOUND. 
I fixed it and now all the PRAGMAs worked fine. 

I thank you very much


-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Janke, Julian
Sent: Mittwoch, 22. April 2015 13:13
To: ambrus at math.bme.hu; General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

Thank you for the hint. I'll check that.

-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Zsb?n Ambrus
Sent: Mittwoch, 22. April 2015 10:58
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On Wed, Apr 22, 2015 at 10:46 AM, Janke, Julian  
wrote:
> I have tested some of the other pragmas and none worked. After 
> discussing with you now I come to the conclusion that the problem is 
> caused more by my local setup. I

In that case, as you have a custom vfs, could you check if it's your vfs that 
is handling those pragmas?  The documentation at 
"http://sqlite.org/c3ref/c_fcntl_busyhandler.html#sqlitefcntlpragma;
describes that when you run a PRAGMA statement on a database, sqlite will call 
the xFileControl method of the vfs file handle (as given in a 
sqlite3_io_methods structure) with SQLITE_FCNTL_PRAGMA as the second parameter. 
 If that method returns SQLITE_OK, then sqlite will assume the vfs has handled 
the pragma, and will not handle it itself.  This could cause pragmas to fail 
silently.

-- Ambrus
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[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Okay, thanks for your reply. I had been concerned that it is the only way to 
implement it by myself in the custom vfs.


-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Richard Hipp
Sent: Mittwoch, 22. April 2015 12:59
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On 4/22/15, Janke, Julian  wrote:
> The embedded system has various storage media, with different read /
> write speeds.
> A quick and dirty test shows that the outsourcing of the journal files
> on a faster medium may be a significant speed boost.
> Is there a possibility to write journal(temporarly) (and later wal
> files when I found the error) files to another directory as the main database?
> (temp_store_directory is marked as deprecated, and thus seems to be no
> option).
>

You can do this, and get away with it, in the highly controlled environment of 
a specific embedded application.  Just modify your custom VFS to automatically 
move journal files to a different directory.  Or even to give them completely 
different names.  As long as the same journal file always gets the same 
modified name whenever that name is used, everything should work.

Generic SQLite does *NOT* make this an option for a good reason.  When 
recovering from a power loss, it is critical that SQLite be able to check for 
the existence of and read the journal file, otherwise database corruption may 
result.  If journal files are on a different volume from the database files, 
then that volume might not be remounted upon reboot, or it might be mounted in 
a different place, thus preventing SQLite from locating the journal file.  We 
have no way to control this in the general case, except to ensure that journal 
files are always in exactly the same directory as the database.  But you can 
control this in your highly controlled and constrained environment, and hence 
you can get away with putting journal files on different volumes from the 
database.
--
D. Richard Hipp
drh at sqlite.org
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Firma: Capgemini Deutschland GmbH
Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Thank you for the hint. I'll check that.

-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Zsb?n Ambrus
Sent: Mittwoch, 22. April 2015 10:58
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On Wed, Apr 22, 2015 at 10:46 AM, Janke, Julian  
wrote:
> I have tested some of the other pragmas and none worked. After
> discussing with you now I come to the conclusion that the problem is
> caused more by my local setup. I

In that case, as you have a custom vfs, could you check if it's your vfs that 
is handling those pragmas?  The documentation at 
"http://sqlite.org/c3ref/c_fcntl_busyhandler.html#sqlitefcntlpragma;
describes that when you run a PRAGMA statement on a database, sqlite will call 
the xFileControl method of the vfs file handle (as given in a 
sqlite3_io_methods structure) with SQLITE_FCNTL_PRAGMA as the second parameter. 
 If that method returns SQLITE_OK, then sqlite will assume the vfs has handled 
the pragma, and will not handle it itself.  This could cause pragmas to fail 
silently.

-- Ambrus
___
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sqlite-users at mailinglists.sqlite.org
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Firma: Capgemini Deutschland GmbH
Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Zsbán Ambrus]

On Wed, Apr 22, 2015 at 10:46 AM, Janke, Julian
 wrote:
> I have tested some of the other pragmas and none worked. After discussing 
> with you now I come to the conclusion that the problem is caused more by my 
> local setup. I

In that case, as you have a custom vfs, could you check if it's your
vfs that is handling those pragmas?  The documentation at
"http://sqlite.org/c3ref/c_fcntl_busyhandler.html#sqlitefcntlpragma;
describes that when you run a PRAGMA statement on a database, sqlite
will call the xFileControl method of the vfs file handle (as given in
a sqlite3_io_methods structure) with SQLITE_FCNTL_PRAGMA as the second
parameter.  If that method returns SQLITE_OK, then sqlite will assume
the vfs has handled the pragma, and will not handle it itself.  This
could cause pragmas to fail silently.

-- Ambrus

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

I have tested some of the other pragmas and none worked. After discussing with 
you now I come to the conclusion that the problem is caused more by my local 
setup. I had hoped to be able to avoid it, but I will now try to debug the 
database and find the error. If I find the error, I will report you.

However, I have one more question:
The embedded system has various storage media, with different read / write 
speeds.
A quick and dirty test shows that the outsourcing of the journal files on a 
faster medium may be a significant speed boost.
Is there a possibility to write journal(temporarly) (and later wal files when I 
found the error) files to another directory as the main database? 
(temp_store_directory is marked as deprecated, and thus seems to be no option).

Thansk a lot or your help


-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Richard Hipp
Sent: Montag, 20. April 2015 16:32
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

If the compile-time options you have shown are complete, then the PRAGMA 
command ought to be working.  But clearly PRAGMA is not working.

Can you do an experimental build that omits all of your -DSQLITE options and 
see if "PRAGMA journal_mode;" and "PRAGMA compile_options;" work then?

What about other PRAGMAs, like "PRAGMA database_list;" and "PRAGMA 
table_info=TABLE;".  See the complete list at 
(https://www.sqlite.org/pragma.html#toc).  Are any pragmas working on your 
system?

On 4/20/15, Janke, Julian  wrote:
> I'm pretty sure that they are completely. Later this discussion I 
> added
> -DSQLITE_DEFAULT_LOCKING_MODE=1
>
> There are only a few non-SQLite-specific options still available.
> Tell me if I'm wrong, but I do not think that are the cause of my problem.
>
> -mcpu=603e
> -fno-common
> -msdata=none
> -fno-jump-tables
> -fno-section-anchors
> -fno-merge-constants
> -fno-builtin
> -nostdlib
> -Werror-implicit-function-declaration
> -Wconversion
> -fstack-usage
> -std=c99
> -c
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of 
> Richard Hipp
> Sent: Montag, 20. April 2015 15:55
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
> On 4/20/15, Janke, Julian  wrote:
>>
>> PRAGMA compile_options; shows 0
>
> This makes me think that the list of compile-time options you showed 
> us earlier is incomplete:
>
> -DSQLITE_ENABLE_MEMSYS5
> -DSQLITE_ENABLE_8_3_NAMES=2
> -DSQLITE_THREADSAFE=0
> -DSQLITE_OS_OTHER=1
> -DSQLITE_ENABLE_API_ARMOR
> -DSQLITE_DEFAULT_MMAP_SIZE=0
> -DSQLITE_TEMP_STORE=0
> -DSQLITE_DEFAULT_CACHE_SIZE=500
>
> Please double-check to ensure that you do not have additional SQLITE 
> defines stuck in a configuration file someplace.
>
>>
>>
>> -Original Message-
>> From: sqlite-users-bounces at mailinglists.sqlite.org
>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of 
>> Richard Hipp
>> Sent: Montag, 20. April 2015 12:18
>> To: General Discussion of SQLite Database
>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>
>> On 4/20/15, Janke, Julian  wrote:
>>> 'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows
>>>
>>> 0: 0 Init 0 0 0
>>> 1: 1 Halt 0 0 0
>>>
>>
>> You should get this:
>>
>> addr  opcode p1p2p3p4 p5  comment
>>   -        -  --  -
>> 0 Init   0 0 000
>> 1 JournalMode0 1 500
>> 2 ResultRow  1 1 000
>> 3 Halt   0 0 000
>>
>> What does: "PRAGMA compile_options;" and "SELECT sqlite_source_id();"
>> show?
>>
>>
>>
>>> Is it the result of what you expected?
>>>
>>> -Original Message-
>>> From: sqlite-users-bounces at mailinglists.sqlite.org
>>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of 
>>> Richard Hipp
>>> Sent: Freitag, 17. April 2015 16:59
>>> To: General Discussion of SQLite Database
>>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>>
>>> On 4/17/15, Janke, Julian  wrote:
>>>> Hello,
>>>> Thanks for your reply.
>>>>
>>>> I changed my code again:
>>>>
>

[sqlite] Problems with pragma journal_mode

[Richard Hipp]

On 4/22/15, Janke, Julian  wrote:
> The embedded system has various storage media, with different read / write
> speeds.
> A quick and dirty test shows that the outsourcing of the journal files on a
> faster medium may be a significant speed boost.
> Is there a possibility to write journal(temporarly) (and later wal files
> when I found the error) files to another directory as the main database?
> (temp_store_directory is marked as deprecated, and thus seems to be no
> option).
>

You can do this, and get away with it, in the highly controlled
environment of a specific embedded application.  Just modify your
custom VFS to automatically move journal files to a different
directory.  Or even to give them completely different names.  As long
as the same journal file always gets the same modified name whenever
that name is used, everything should work.

Generic SQLite does *NOT* make this an option for a good reason.  When
recovering from a power loss, it is critical that SQLite be able to
check for the existence of and read the journal file, otherwise
database corruption may result.  If journal files are on a different
volume from the database files, then that volume might not be
remounted upon reboot, or it might be mounted in a different place,
thus preventing SQLite from locating the journal file.  We have no way
to control this in the general case, except to ensure that journal
files are always in exactly the same directory as the database.  But
you can control this in your highly controlled and constrained
environment, and hence you can get away with putting journal files on
different volumes from the database.
-- 
D. Richard Hipp
drh at sqlite.org

[sqlite] Problems with pragma journal_mode

[Richard Hipp]

On 4/22/15, Zsb?n Ambrus  wrote:
>
> In that case, as you have a custom vfs, could you check if it's your
> vfs that is handling those pragmas?  The documentation at
> "http://sqlite.org/c3ref/c_fcntl_busyhandler.html#sqlitefcntlpragma;
> describes that when you run a PRAGMA statement on a database, sqlite
> will call the xFileControl method of the vfs file handle (as given in
> a sqlite3_io_methods structure) with SQLITE_FCNTL_PRAGMA as the second
> parameter.  If that method returns SQLITE_OK, then sqlite will assume
> the vfs has handled the pragma, and will not handle it itself.  This
> could cause pragmas to fail silently.

Ah - Nice insight, Ambrus.  This theory nicely covers the facts.
Thank you for thinking of this!
-- 
D. Richard Hipp
drh at sqlite.org

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

I'm pretty sure that they are completely. Later this discussion I added 
-DSQLITE_DEFAULT_LOCKING_MODE=1 

There are only a few non-SQLite-specific options still available.
Tell me if I'm wrong, but I do not think that are the cause of my problem.

-mcpu=603e 
-fno-common 
-msdata=none 
-fno-jump-tables 
-fno-section-anchors 
-fno-merge-constants 
-fno-builtin 
-nostdlib 
-Werror-implicit-function-declaration 
-Wconversion 
-fstack-usage  
-std=c99 
-c 

-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Richard Hipp
Sent: Montag, 20. April 2015 15:55
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On 4/20/15, Janke, Julian  wrote:
>
> PRAGMA compile_options; shows 0

This makes me think that the list of compile-time options you showed us earlier 
is incomplete:

-DSQLITE_ENABLE_MEMSYS5
-DSQLITE_ENABLE_8_3_NAMES=2
-DSQLITE_THREADSAFE=0
-DSQLITE_OS_OTHER=1
-DSQLITE_ENABLE_API_ARMOR
-DSQLITE_DEFAULT_MMAP_SIZE=0
-DSQLITE_TEMP_STORE=0
-DSQLITE_DEFAULT_CACHE_SIZE=500

Please double-check to ensure that you do not have additional SQLITE defines 
stuck in a configuration file someplace.

>
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of 
> Richard Hipp
> Sent: Montag, 20. April 2015 12:18
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
> On 4/20/15, Janke, Julian  wrote:
>> 'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows
>>
>> 0: 0 Init 0 0 0
>> 1: 1 Halt 0 0 0
>>
>
> You should get this:
>
> addr  opcode p1p2p3p4 p5  comment
>   -        -  --  -
> 0 Init   0 0 000
> 1 JournalMode0 1 500
> 2 ResultRow  1 1 000
> 3 Halt   0 0 000
>
> What does: "PRAGMA compile_options;" and "SELECT sqlite_source_id();" show?
>
>
>
>> Is it the result of what you expected?
>>
>> -Original Message-
>> From: sqlite-users-bounces at mailinglists.sqlite.org
>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of 
>> Richard Hipp
>> Sent: Freitag, 17. April 2015 16:59
>> To: General Discussion of SQLite Database
>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>
>> On 4/17/15, Janke, Julian  wrote:
>>> Hello,
>>> Thanks for your reply.
>>>
>>> I changed my code again:
>>>
>>> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
>>> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", 
>>> testCallbackPrint, 0, );
>>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, 
>>> , NULL);
>>> --> SQLITE_OK
>>> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE
>>
>> I do not understand this.  "PRAGMA journal_mode" should always give a 
>> return value, even when it fails.  sqlite3_step() should have 
>> returned SQLITE_ROW.
>>
>> Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that 
>> you get multiple rows of output in that case.
>>
>>
>>> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", 
>>> testCallbackPrint, 0, );
>>> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
>>> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
>>> 8) rc = sqlite3_close(db); --> SQLITE_OK
>>>
>>> Repeated the same steps with
>>>
>>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, , 
>>> NULL); --> SQLITE_OK
>>>
>>> To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should 
>>> be returned.
>>>
>>> "These routines may only be called when the most recent call to
>>> sqlite3_step() has returned SQLITE_ROW and neither sqlite3_reset() 
>>> nor
>>> sqlite3_finalize() have been called subsequently."
>>>
>>> It looks as if all PRAGMA instructions are completely ignored, since 
>>> the query for the status of the JOURNAL_MODE returns no result.
>>>
>>> Is it possible that I have turned off PRAMAs by anything or 
>>> something is missing, so PRAMAs can run?
>>>
>>> Thanks for your help
>>>
>>>
>>> -Original Message--

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

SELECT sqlite_source_id(); shows:

2015-02-25 13:29:11 9d6c1880fb75660bbabd693175579529785f8a6b

And

PRAGMA compile_options; shows 0


-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Richard Hipp
Sent: Montag, 20. April 2015 12:18
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On 4/20/15, Janke, Julian  wrote:
> 'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows
>
> 0: 0 Init 0 0 0
> 1: 1 Halt 0 0 0
>

You should get this:

addr  opcode p1p2p3p4 p5  comment
  -        -  --  -
0 Init   0 0 000
1 JournalMode0 1 500
2 ResultRow  1 1 000
3 Halt   0 0 000

What does: "PRAGMA compile_options;" and "SELECT sqlite_source_id();" show?



> Is it the result of what you expected?
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
> Richard Hipp
> Sent: Freitag, 17. April 2015 16:59
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
> On 4/17/15, Janke, Julian  wrote:
>> Hello,
>> Thanks for your reply.
>>
>> I changed my code again:
>>
>> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
>> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>> testCallbackPrint, 0, );
>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, ,
>> NULL);
>> --> SQLITE_OK
>> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE
>
> I do not understand this.  "PRAGMA journal_mode" should always give a
> return value, even when it fails.  sqlite3_step() should have returned 
> SQLITE_ROW.
>
> Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that
> you get multiple rows of output in that case.
>
>
>> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>> testCallbackPrint, 0, );
>> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
>> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
>> 8) rc = sqlite3_close(db); --> SQLITE_OK
>>
>> Repeated the same steps with
>>
>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, ,
>> NULL); --> SQLITE_OK
>>
>> To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should
>> be returned.
>>
>> "These routines may only be called when the most recent call to
>> sqlite3_step() has returned SQLITE_ROW and neither sqlite3_reset()
>> nor
>> sqlite3_finalize() have been called subsequently."
>>
>> It looks as if all PRAGMA instructions are completely ignored, since
>> the query for the status of the JOURNAL_MODE returns no result.
>>
>> Is it possible that I have turned off PRAMAs by anything or something
>> is missing, so PRAMAs can run?
>>
>> Thanks for your help
>>
>>
>> -Original Message-
>> From: sqlite-users-bounces at mailinglists.sqlite.org
>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
>> Simon Slavin
>> Sent: Donnerstag, 16. April 2015 17:56
>> To: General Discussion of SQLite Database
>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>
>>
>> On 16 Apr 2015, at 2:33pm, Janke, Julian 
>> wrote:
>>
>>> rc = sqlite3_step(stmt);
>>> --> returns SQLITE_DONE
>>
>> After the above two lines, print the value returned by
>>
>> sqlite3_column_text(stmt, 0)
>>
>> I'm not good at C off the top of my head but I think it's something
>> like
>>
>> -
>>
>> const unsigned char * theText;
>>
>> [...]
>>
>> rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, ,
>> NULL);
>>
>> rc = sqlite3_step(stmt);
>> theText  = sqlite3_column_text (stmt, 0); printf ("text returned:
>> %s", theText);
>>
>> rc = sqlite3_finalize(stmt);
>>
>> -
>>
>> Hope if I got it wrong someone else will tell you.  By the way, you
>> can also check the values returned from sqlite3_finalize() and
>> sqlite3_close() since they can tell you useful things if something
>> went wrong.
>>
>> Simon.
>> 

[sqlite] Problems with pragma journal_mode

[Richard Hipp]

If the compile-time options you have shown are complete, then the
PRAGMA command ought to be working.  But clearly PRAGMA is not
working.

Can you do an experimental build that omits all of your -DSQLITE
options and see if "PRAGMA journal_mode;" and "PRAGMA
compile_options;" work then?

What about other PRAGMAs, like "PRAGMA database_list;" and "PRAGMA
table_info=TABLE;".  See the complete list at
(https://www.sqlite.org/pragma.html#toc).  Are any pragmas working on
your system?

On 4/20/15, Janke, Julian  wrote:
> I'm pretty sure that they are completely. Later this discussion I added
> -DSQLITE_DEFAULT_LOCKING_MODE=1
>
> There are only a few non-SQLite-specific options still available.
> Tell me if I'm wrong, but I do not think that are the cause of my problem.
>
> -mcpu=603e
> -fno-common
> -msdata=none
> -fno-jump-tables
> -fno-section-anchors
> -fno-merge-constants
> -fno-builtin
> -nostdlib
> -Werror-implicit-function-declaration
> -Wconversion
> -fstack-usage
> -std=c99
> -c
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of Richard
> Hipp
> Sent: Montag, 20. April 2015 15:55
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
> On 4/20/15, Janke, Julian  wrote:
>>
>> PRAGMA compile_options; shows 0
>
> This makes me think that the list of compile-time options you showed us
> earlier is incomplete:
>
> -DSQLITE_ENABLE_MEMSYS5
> -DSQLITE_ENABLE_8_3_NAMES=2
> -DSQLITE_THREADSAFE=0
> -DSQLITE_OS_OTHER=1
> -DSQLITE_ENABLE_API_ARMOR
> -DSQLITE_DEFAULT_MMAP_SIZE=0
> -DSQLITE_TEMP_STORE=0
> -DSQLITE_DEFAULT_CACHE_SIZE=500
>
> Please double-check to ensure that you do not have additional SQLITE defines
> stuck in a configuration file someplace.
>
>>
>>
>> -Original Message-
>> From: sqlite-users-bounces at mailinglists.sqlite.org
>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
>> Richard Hipp
>> Sent: Montag, 20. April 2015 12:18
>> To: General Discussion of SQLite Database
>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>
>> On 4/20/15, Janke, Julian  wrote:
>>> 'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows
>>>
>>> 0: 0 Init 0 0 0
>>> 1: 1 Halt 0 0 0
>>>
>>
>> You should get this:
>>
>> addr  opcode p1p2p3p4 p5  comment
>>   -        -  --  -
>> 0 Init   0 0 000
>> 1 JournalMode0 1 500
>> 2 ResultRow  1 1 000
>> 3 Halt   0 0 000
>>
>> What does: "PRAGMA compile_options;" and "SELECT sqlite_source_id();"
>> show?
>>
>>
>>
>>> Is it the result of what you expected?
>>>
>>> -Original Message-
>>> From: sqlite-users-bounces at mailinglists.sqlite.org
>>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
>>> Richard Hipp
>>> Sent: Freitag, 17. April 2015 16:59
>>> To: General Discussion of SQLite Database
>>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>>
>>> On 4/17/15, Janke, Julian  wrote:
>>>> Hello,
>>>> Thanks for your reply.
>>>>
>>>> I changed my code again:
>>>>
>>>> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
>>>> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>>>> testCallbackPrint, 0, );
>>>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24,
>>>> , NULL);
>>>> --> SQLITE_OK
>>>> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE
>>>
>>> I do not understand this.  "PRAGMA journal_mode" should always give a
>>> return value, even when it fails.  sqlite3_step() should have
>>> returned SQLITE_ROW.
>>>
>>> Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that
>>> you get multiple rows of output in that case.
>>>
>>>
>>>> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>>>> testCallbackPrint, 0, );
>>>> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
>>>> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
>>>

[sqlite] Problems with pragma journal_mode

[Richard Hipp]

On 4/20/15, Janke, Julian  wrote:
>
> PRAGMA compile_options; shows 0

This makes me think that the list of compile-time options you showed
us earlier is incomplete:

-DSQLITE_ENABLE_MEMSYS5
-DSQLITE_ENABLE_8_3_NAMES=2
-DSQLITE_THREADSAFE=0
-DSQLITE_OS_OTHER=1
-DSQLITE_ENABLE_API_ARMOR
-DSQLITE_DEFAULT_MMAP_SIZE=0
-DSQLITE_TEMP_STORE=0
-DSQLITE_DEFAULT_CACHE_SIZE=500

Please double-check to ensure that you do not have additional SQLITE
defines stuck in a configuration file someplace.

>
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of Richard
> Hipp
> Sent: Montag, 20. April 2015 12:18
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
> On 4/20/15, Janke, Julian  wrote:
>> 'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows
>>
>> 0: 0 Init 0 0 0
>> 1: 1 Halt 0 0 0
>>
>
> You should get this:
>
> addr  opcode p1p2p3p4 p5  comment
>   -        -  --  -
> 0 Init   0 0 000
> 1 JournalMode0 1 500
> 2 ResultRow  1 1 000
> 3 Halt   0 0 000
>
> What does: "PRAGMA compile_options;" and "SELECT sqlite_source_id();" show?
>
>
>
>> Is it the result of what you expected?
>>
>> -Original Message-
>> From: sqlite-users-bounces at mailinglists.sqlite.org
>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
>> Richard Hipp
>> Sent: Freitag, 17. April 2015 16:59
>> To: General Discussion of SQLite Database
>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>
>> On 4/17/15, Janke, Julian  wrote:
>>> Hello,
>>> Thanks for your reply.
>>>
>>> I changed my code again:
>>>
>>> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
>>> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>>> testCallbackPrint, 0, );
>>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, ,
>>> NULL);
>>> --> SQLITE_OK
>>> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE
>>
>> I do not understand this.  "PRAGMA journal_mode" should always give a
>> return value, even when it fails.  sqlite3_step() should have returned
>> SQLITE_ROW.
>>
>> Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that
>> you get multiple rows of output in that case.
>>
>>
>>> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>>> testCallbackPrint, 0, );
>>> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
>>> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
>>> 8) rc = sqlite3_close(db); --> SQLITE_OK
>>>
>>> Repeated the same steps with
>>>
>>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, ,
>>> NULL); --> SQLITE_OK
>>>
>>> To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should
>>> be returned.
>>>
>>> "These routines may only be called when the most recent call to
>>> sqlite3_step() has returned SQLITE_ROW and neither sqlite3_reset()
>>> nor
>>> sqlite3_finalize() have been called subsequently."
>>>
>>> It looks as if all PRAGMA instructions are completely ignored, since
>>> the query for the status of the JOURNAL_MODE returns no result.
>>>
>>> Is it possible that I have turned off PRAMAs by anything or something
>>> is missing, so PRAMAs can run?
>>>
>>> Thanks for your help
>>>
>>>
>>> -Original Message-
>>> From: sqlite-users-bounces at mailinglists.sqlite.org
>>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
>>> Simon Slavin
>>> Sent: Donnerstag, 16. April 2015 17:56
>>> To: General Discussion of SQLite Database
>>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>>
>>>
>>> On 16 Apr 2015, at 2:33pm, Janke, Julian 
>>> wrote:
>>>
>>>> rc = sqlite3_step(stmt);
>>>> --> returns SQLITE_DONE
>>>
>>> After the above two lines, print the value returned by
>>>
>>> sqlite3_column_text(stmt, 0)
>>>
>>> I'm not good at C off the top of my head but I think it's

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows

0: 0 Init 0 0 0 
1: 1 Halt 0 0 0

Is it the result of what you expected?

-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Richard Hipp
Sent: Freitag, 17. April 2015 16:59
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On 4/17/15, Janke, Julian  wrote:
> Hello,
> Thanks for your reply.
>
> I changed my code again:
>
> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", 
> testCallbackPrint, 0, );
> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , 
> NULL);
> --> SQLITE_OK
> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE

I do not understand this.  "PRAGMA journal_mode" should always give a return 
value, even when it fails.  sqlite3_step() should have returned SQLITE_ROW.

Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that you get 
multiple rows of output in that case.


> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", 
> testCallbackPrint, 0, );
> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
> 8) rc = sqlite3_close(db); --> SQLITE_OK
>
> Repeated the same steps with
>
> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, , 
> NULL); --> SQLITE_OK
>
> To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should be 
> returned.
>
> "These routines may only be called when the most recent call to
> sqlite3_step() has returned SQLITE_ROW and neither sqlite3_reset() nor
> sqlite3_finalize() have been called subsequently."
>
> It looks as if all PRAGMA instructions are completely ignored, since 
> the query for the status of the JOURNAL_MODE returns no result.
>
> Is it possible that I have turned off PRAMAs by anything or something 
> is missing, so PRAMAs can run?
>
> Thanks for your help
>
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of 
> Simon Slavin
> Sent: Donnerstag, 16. April 2015 17:56
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
>
> On 16 Apr 2015, at 2:33pm, Janke, Julian 
> wrote:
>
>> rc = sqlite3_step(stmt);
>> --> returns SQLITE_DONE
>
> After the above two lines, print the value returned by
>
> sqlite3_column_text(stmt, 0)
>
> I'm not good at C off the top of my head but I think it's something 
> like
>
> -
>
> const unsigned char * theText;
>
> [...]
>
> rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , 
> NULL);
>
> rc = sqlite3_step(stmt);
> theText  = sqlite3_column_text (stmt, 0); printf ("text returned: %s", 
> theText);
>
> rc = sqlite3_finalize(stmt);
>
> -
>
> Hope if I got it wrong someone else will tell you.  By the way, you 
> can also check the values returned from sqlite3_finalize() and 
> sqlite3_close() since they can tell you useful things if something went wrong.
>
> Simon.
> ___
> sqlite-users mailing list
> sqlite-users at mailinglists.sqlite.org
> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
>
> 
>
> Firma: Capgemini Deutschland GmbH
> Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. 
> Michael Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. 
> Volkmar Varnhagen
>
> Amtsgericht Berlin-Charlottenburg, HRB 98814 This message contains 
> information that may be privileged or confidential and is the property 
> of the Capgemini Group. It is intended only for the person to whom it 
> is addressed. If you are not the intended recipient, you are not 
> authorized to read, print, retain, copy, disseminate, distribute, or 
> use this message or any part thereof. If you receive this message in 
> error, please notify the sender immediately and delete all copies of this 
> message.
> ___
> sqlite-users mailing list
> sqlite-users at mailinglists.sqlite.org
> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
>


--
D. Richard Hipp
drh at sqlite.org
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[sqlite] Problems with pragma journal_mode

[Richard Hipp]

On 4/20/15, Janke, Julian  wrote:
> 'EXPLAIN PRAGMA journal_mode=WAL' returns 2 rows
>
> 0: 0 Init 0 0 0
> 1: 1 Halt 0 0 0
>

You should get this:

addr  opcode p1p2p3p4 p5  comment
  -        -  --  -
0 Init   0 0 000
1 JournalMode0 1 500
2 ResultRow  1 1 000
3 Halt   0 0 000

What does: "PRAGMA compile_options;" and "SELECT sqlite_source_id();" show?



> Is it the result of what you expected?
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of Richard
> Hipp
> Sent: Freitag, 17. April 2015 16:59
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
> On 4/17/15, Janke, Julian  wrote:
>> Hello,
>> Thanks for your reply.
>>
>> I changed my code again:
>>
>> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
>> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>> testCallbackPrint, 0, );
>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, ,
>> NULL);
>> --> SQLITE_OK
>> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE
>
> I do not understand this.  "PRAGMA journal_mode" should always give a return
> value, even when it fails.  sqlite3_step() should have returned SQLITE_ROW.
>
> Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that you get
> multiple rows of output in that case.
>
>
>> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
>> testCallbackPrint, 0, );
>> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
>> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
>> 8) rc = sqlite3_close(db); --> SQLITE_OK
>>
>> Repeated the same steps with
>>
>> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, ,
>> NULL); --> SQLITE_OK
>>
>> To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should be
>> returned.
>>
>> "These routines may only be called when the most recent call to
>> sqlite3_step() has returned SQLITE_ROW and neither sqlite3_reset() nor
>> sqlite3_finalize() have been called subsequently."
>>
>> It looks as if all PRAGMA instructions are completely ignored, since
>> the query for the status of the JOURNAL_MODE returns no result.
>>
>> Is it possible that I have turned off PRAMAs by anything or something
>> is missing, so PRAMAs can run?
>>
>> Thanks for your help
>>
>>
>> -Original Message-
>> From: sqlite-users-bounces at mailinglists.sqlite.org
>> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of
>> Simon Slavin
>> Sent: Donnerstag, 16. April 2015 17:56
>> To: General Discussion of SQLite Database
>> Subject: Re: [sqlite] Problems with pragma journal_mode
>>
>>
>> On 16 Apr 2015, at 2:33pm, Janke, Julian 
>> wrote:
>>
>>> rc = sqlite3_step(stmt);
>>> --> returns SQLITE_DONE
>>
>> After the above two lines, print the value returned by
>>
>> sqlite3_column_text(stmt, 0)
>>
>> I'm not good at C off the top of my head but I think it's something
>> like
>>
>> -
>>
>> const unsigned char * theText;
>>
>> [...]
>>
>> rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, ,
>> NULL);
>>
>> rc = sqlite3_step(stmt);
>> theText  = sqlite3_column_text (stmt, 0); printf ("text returned: %s",
>> theText);
>>
>> rc = sqlite3_finalize(stmt);
>>
>> -
>>
>> Hope if I got it wrong someone else will tell you.  By the way, you
>> can also check the values returned from sqlite3_finalize() and
>> sqlite3_close() since they can tell you useful things if something went
>> wrong.
>>
>> Simon.
>> ___
>> sqlite-users mailing list
>> sqlite-users at mailinglists.sqlite.org
>> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
>>
>> 
>>
>> Firma: Capgemini Deutschland GmbH
>> Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr.
>> Michael Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr.
>> V

[sqlite] Problems with pragma journal_mode

[Dominique Devienne]

On Fri, Apr 17, 2015 at 12:59 PM, Janke, Julian 
wrote:

> Unfortunately, I can't run the shell tool on the es and try the same
> sequence of commands.
>

Why? Don't you have some kind of shell on that embedded system that can run
executables?

According to https://www.sqlite.org/howtocompile.html, the amalgamation
also comes with shell.c, the source code for the SQLite shell, and you can
compile it into an exe with your VFS, and then easily test everything at
the command line of the board/embedded OS. --DD

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Unfortunately not.
There are no shell on the system to which I have access as an application 
developer,
so I don't can run executables.

The only thing I can do is to download c-code applications on a given interface 
to the board.


-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Dominique 
Devienne
Sent: Freitag, 17. April 2015 13:50
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On Fri, Apr 17, 2015 at 12:59 PM, Janke, Julian 
wrote:

> Unfortunately, I can't run the shell tool on the es and try the same
> sequence of commands.
>

Why? Don't you have some kind of shell on that embedded system that can run 
executables?

According to https://www.sqlite.org/howtocompile.html, the amalgamation also 
comes with shell.c, the source code for the SQLite shell, and you can compile 
it into an exe with your VFS, and then easily test everything at the command 
line of the board/embedded OS. --DD 
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Firma: Capgemini Deutschland GmbH
Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Simon Slavin]

On 17 Apr 2015, at 11:59am, Janke, Julian  wrote:

> I've changed the stmt to "SELECT 'Hello World !!';"
> In this case,
> 
> sqlite3_step() returns SQLITE_ROW
> sqlite3_column_text() returns 'Hello World !!'
> 
> That, looks right.

I agree.  And it shows that your C code is working perfectly.  For comparison I 
will show you what the shell tool does with the PRAGMA command:

dyn-171-167:~ simon$ sqlite3 ~/Desktop/test.sqlite
SQLite version 3.8.5 2014-08-15 22:37:57
Enter ".help" for usage hints.
sqlite> CREATE TABLE myTable (myColumn TEXT);
sqlite> INSERT INTO myTable VALUES ('first line');
sqlite> INSERT INTO myTable VALUES ('second line');
sqlite> SELECT * FROM myTable;
first line
second line
sqlite> PRAGMA journal_mode=WAL;
wal
sqlite> PRAGMA journal_mode=WAL;
wal
sqlite> .quit

As you can see, the PRAGMA command returns a response of 'wal' even if the mode 
is already WAL.  My understanding of your previous answers is that the command 
returns SQLITE_OK, but no lines of data.  That does seem wrong to me.

I suspect that you are coming up with some aspect of writing your own VFS.  I'm 
sorry but I do not know enough about writing your own VFS to understand what to 
do next.  I hope somebody else reading this can help you further.

Simon.

[sqlite] Problems with pragma journal_mode

[Simon Slavin]

On 17 Apr 2015, at 11:12am, Janke, Julian  wrote:

> I changed my code again:

Move the DROP TABLE command on line 5 to after the _finalize() call.  But I 
don't think it'll make any difference.

You should not be getting SQLITE_DONE back from your call to _step().  The 
documentation says that that PRAGMA command should return a row of data.  
Please try changing the PRAMGA command to

sqlite3_prepare_v2(db, "SELECT 'Hello World !!';", 24, , NULL);

and see what you get back from it.

> It looks as if all PRAGMA instructions are completely ignored,
> since the query for the status of the JOURNAL_MODE returns no result.
> 
> Is it possible that I have turned off PRAMAs by anything or something is 
> missing, so PRAMAs can run?

No.  I'm coming to the conclusion that there's something wrong with your 
compilation process.

How are you getting your sqlite3 library ?  Have you downloaded the 
amalgamation source code and included it in your project ?  If not, please try 
doing this.

Can you download the sqlite3 shell tool and try the same sequence of commands ? 
 You can find it here:



Simon.

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Yes, I downloaded the amalgamation and included it into my project. Since it is 
an embedded system with a not out of the box supported operating system, I 
wrote my own vfs. Insert, select, delete operations properly work on a database 
and as desired.

I've changed the stmt to "SELECT 'Hello World !!';"
In this case,

sqlite3_step() returns SQLITE_ROW
sqlite3_column_text() returns 'Hello World !!'

That, looks right.

Unfortunately, I can't run the shell tool on the es and try the same sequence 
of cammands.


If you think that there's something wrong with the compilation process,
should then also standard SQL instructions do not work?



-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Simon Slavin
Sent: Freitag, 17. April 2015 12:34
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode


On 17 Apr 2015, at 11:12am, Janke, Julian  wrote:

> I changed my code again:

Move the DROP TABLE command on line 5 to after the _finalize() call.  But I 
don't think it'll make any difference.

You should not be getting SQLITE_DONE back from your call to _step().  The 
documentation says that that PRAGMA command should return a row of data.  
Please try changing the PRAMGA command to

sqlite3_prepare_v2(db, "SELECT 'Hello World !!';", 24, , NULL);

and see what you get back from it.

> It looks as if all PRAGMA instructions are completely ignored, since
> the query for the status of the JOURNAL_MODE returns no result.
>
> Is it possible that I have turned off PRAMAs by anything or something is 
> missing, so PRAMAs can run?

No.  I'm coming to the conclusion that there's something wrong with your 
compilation process.

How are you getting your sqlite3 library ?  Have you downloaded the 
amalgamation source code and included it in your project ?  If not, please try 
doing this.

Can you download the sqlite3 shell tool and try the same sequence of commands ? 
 You can find it here:

<https://www.sqlite.org/download.html>

Simon.
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Firma: Capgemini Deutschland GmbH
Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Richard Hipp]

On 4/17/15, Janke, Julian  wrote:
> Hello,
> Thanks for your reply.
>
> I changed my code again:
>
> 1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
> 2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
> testCallbackPrint, 0, );
> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , NULL);
> --> SQLITE_OK
> 4) rc = sqlite3_step(stmt); --> SQLITE_DONE

I do not understand this.  "PRAGMA journal_mode" should always give a
return value, even when it fails.  sqlite3_step() should have returned
SQLITE_ROW.

Please try instead, "EXPLAIN PRAGMA journal_mode=WAL".  Verify that
you get multiple rows of output in that case.


> 5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;",
> testCallbackPrint, 0, );
> 6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
> 7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
> 8) rc = sqlite3_close(db); --> SQLITE_OK
>
> Repeated the same steps with
>
> 3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, , NULL); -->
> SQLITE_OK
>
> To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should be
> returned.
>
> "These routines may only be called when the most recent call to
> sqlite3_step() has returned SQLITE_ROW and neither sqlite3_reset() nor
> sqlite3_finalize() have been called subsequently."
>
> It looks as if all PRAGMA instructions are completely ignored,
> since the query for the status of the JOURNAL_MODE returns no result.
>
> Is it possible that I have turned off PRAMAs by anything or something is
> missing, so PRAMAs can run?
>
> Thanks for your help
>
>
> -Original Message-
> From: sqlite-users-bounces at mailinglists.sqlite.org
> [mailto:sqlite-users-bounces at mailinglists.sqlite.org] On Behalf Of Simon
> Slavin
> Sent: Donnerstag, 16. April 2015 17:56
> To: General Discussion of SQLite Database
> Subject: Re: [sqlite] Problems with pragma journal_mode
>
>
> On 16 Apr 2015, at 2:33pm, Janke, Julian 
> wrote:
>
>> rc = sqlite3_step(stmt);
>> --> returns SQLITE_DONE
>
> After the above two lines, print the value returned by
>
> sqlite3_column_text(stmt, 0)
>
> I'm not good at C off the top of my head but I think it's something like
>
> -
>
> const unsigned char * theText;
>
> [...]
>
> rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , NULL);
>
> rc = sqlite3_step(stmt);
> theText  = sqlite3_column_text (stmt, 0); printf ("text returned: %s",
> theText);
>
> rc = sqlite3_finalize(stmt);
>
> -
>
> Hope if I got it wrong someone else will tell you.  By the way, you can also
> check the values returned from sqlite3_finalize() and sqlite3_close() since
> they can tell you useful things if something went wrong.
>
> Simon.
> ___
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>
> 
>
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>
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> This message contains information that may be privileged or confidential and
> is the property of the Capgemini Group. It is intended only for the person
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-- 
D. Richard Hipp
drh at sqlite.org

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Hello,
Thanks for your reply.

I changed my code again:

1) rc = sqlite3_open(dbPath, ); --> SQLITE_OK
2) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", 
testCallbackPrint, 0, );
3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , NULL); 
--> SQLITE_OK
4) rc = sqlite3_step(stmt); --> SQLITE_DONE
5) rc = sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", 
testCallbackPrint, 0, );
6) txt  = sqlite3_column_text (stmt, 0); --> returns an empty string
7) rc = sqlite3_finalize(stmt); --> SQLITE_OK
8) rc = sqlite3_close(db); --> SQLITE_OK

Repeated the same steps with

3) rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode;", 24, , NULL); --> 
SQLITE_OK

To my knowledge, at line 4 SQLITE_ROW instead of SQLITE_DONE should be returned.

"These routines may only be called when the most recent call to sqlite3_step() 
has returned SQLITE_ROW and neither sqlite3_reset() nor sqlite3_finalize() have 
been called subsequently."

It looks as if all PRAGMA instructions are completely ignored,
since the query for the status of the JOURNAL_MODE returns no result.

Is it possible that I have turned off PRAMAs by anything or something is 
missing, so PRAMAs can run?

Thanks for your help


-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Simon Slavin
Sent: Donnerstag, 16. April 2015 17:56
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode


On 16 Apr 2015, at 2:33pm, Janke, Julian  wrote:

> rc = sqlite3_step(stmt);
> --> returns SQLITE_DONE

After the above two lines, print the value returned by

sqlite3_column_text(stmt, 0)

I'm not good at C off the top of my head but I think it's something like

-

const unsigned char * theText;

[...]

rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , NULL);

rc = sqlite3_step(stmt);
theText  = sqlite3_column_text (stmt, 0); printf ("text returned: %s", theText);

rc = sqlite3_finalize(stmt);

-

Hope if I got it wrong someone else will tell you.  By the way, you can also 
check the values returned from sqlite3_finalize() and sqlite3_close() since 
they can tell you useful things if something went wrong.

Simon.
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Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
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[sqlite] Problems with pragma journal_mode

[Simon Slavin]

On 16 Apr 2015, at 2:33pm, Janke, Julian  wrote:

> rc = sqlite3_step(stmt);
> --> returns SQLITE_DONE

After the above two lines, print the value returned by

sqlite3_column_text(stmt, 0)

I'm not good at C off the top of my head but I think it's something like

-

const unsigned char * theText;

[...]

rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , NULL);

rc = sqlite3_step(stmt);
theText  = sqlite3_column_text (stmt, 0);
printf ("text returned: %s", theText);

rc = sqlite3_finalize(stmt);

-

Hope if I got it wrong someone else will tell you.  By the way, you can also 
check the values returned from sqlite3_finalize() and sqlite3_close() since 
they can tell you useful things if something went wrong.

Simon.

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Ok, actually I'm a little bit confused, never used prepare(), step() and 
finalize() manually before.
Maybe it's his absolute basics are missing me here, but maybe someone can still 
help me
On which point I should get "wal" back?

I changed my code to the following:

rc = sqlite3_open(dbPath, );
sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", testCallbackPrint, 0, 
);
rc = sqlite3_prepare_v2(db, "PRAGMA journal_mode=WAL;", 24, , NULL);
--> returns SQLITE_OK

rc = sqlite3_step(stmt);
--> returns SQLITE_DONE

sqlite3_finalize(stmt);
sqlite3_exec(db, "DROP TABLE IF EXISTS nosuchtable;", testCallbackPrint, 0, 
);
[...]
sqlite3_close(db);


Thanks.

-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Simon Slavin
Sent: Donnerstag, 16. April 2015 14:15
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode


On 16 Apr 2015, at 10:10am, Janke, Julian  wrote:

> rc = sqlite3_open(dbPath, );
> rc = sqlite3_exec(db, "PRAGMA journal_mode=WAL;", testCallbackPrint,
> 0, ); [?] sqlite3_close(db);

Execute your PRAGMA as if it's a SELECT call (i.e. use sqlite3_prepare_v2(), 
sqlite3_step(), and sqlite3_finalize()) and check the value returned by 
_step().  If the command worked you should get "wal" back.

Before and after your existing PRAGMA, submit any SQL command that needs 
database access.  For example

DROP TABLE IF EXISTS nosuchtable;
PRAGMA journal_mode=WAL;
DROP TABLE IF EXISTS nosuchtable;

You can use _exec() for these other commands.  I do not know that this is 
definitely your problem, but I seem to remember that there has to be some kind 
of file access for a journal mode change to take effect.

In connection with another post to this thread, you should be able to change 
the journal mode at any time you have the only connection to the database.  
This includes changing between traditional journal modes and WAL mode.

Simon.
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Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Simon Slavin]

On 16 Apr 2015, at 10:10am, Janke, Julian  wrote:

> rc = sqlite3_open(dbPath, );
> rc = sqlite3_exec(db, "PRAGMA journal_mode=WAL;", testCallbackPrint, 0, 
> );
> [?]
> sqlite3_close(db);

Execute your PRAGMA as if it's a SELECT call (i.e. use sqlite3_prepare_v2(), 
sqlite3_step(), and sqlite3_finalize()) and check the value returned by 
_step().  If the command worked you should get "wal" back.

Before and after your existing PRAGMA, submit any SQL command that needs 
database access.  For example

DROP TABLE IF EXISTS nosuchtable;
PRAGMA journal_mode=WAL;
DROP TABLE IF EXISTS nosuchtable;

You can use _exec() for these other commands.  I do not know that this is 
definitely your problem, but I seem to remember that there has to be some kind 
of file access for a journal mode change to take effect.

In connection with another post to this thread, you should be able to change 
the journal mode at any time you have the only connection to the database.  
This includes changing between traditional journal modes and WAL mode.

Simon.

[sqlite] Problems with pragma journal_mode

[Clemens Ladisch]

Janke, Julian wrote:
> PRAGMA journal_mode=WAL;
>
> Unfortunately, after these lines, the journal mode is not changed.
>
> -DSQLITE_OS_OTHER=1

Do you have mmap support?

 says:
| WAL normally requires that the VFS support shared-memory primitives.
| The built-in unix and windows VFSes support this but third-party
| extension VFSes for custom operating systems might not.

But  says:
| Use of WAL Without Shared-Memory
|
| Beginning in SQLite version 3.7.4, WAL databases can be created, read,
| and written even if shared memory is unavailable as long as the
| locking_mode is set to EXCLUSIVE before the first attempted access. In
| other words, a process can interact with a WAL database without using
| shared memory if that process is guaranteed to be the only process
| accessing the database. This feature allows WAL databases to be
| created, read, and written by legacy VFSes that lack the "version 2"
| shared-memory methods xShmMap, xShmLock, xShmBarrier, and xShmUnmap on
| the sqlite3_io_methods object.


Regards,
Clemens

[sqlite] Problems with pragma journal_mode

[Dominique Devienne]

On Thu, Apr 16, 2015 at 11:10 AM, Janke, Julian 
wrote:

> I want to change the journal mode of a database to WAL. So I did the
> following:
>
> rc = sqlite3_open(dbPath, );
> rc = sqlite3_exec(db, "PRAGMA journal_mode=WAL;", testCallbackPrint, 0,
> );
> [?]
> sqlite3_close(db);
>
> Unfortunately, after these lines, the journal mode is not changed. The
> sqlite3_exec function returns SQLITE_OK (0),
>

>From http://www.sqlite.org/pragma.html#pragma_journal_mode:
The WAL journaling mode is persistent; after being set it stays in effect
across multiple database connections and after closing and reopening the
database

And once set, you cannot change it I believe. You decide on WAL or non-WAL
before creating any object in the DB, and from that point on, you can't
change it. --DD

[sqlite] Problems with pragma journal_mode

[Simon Davies]

On 16 April 2015 at 10:10, Janke, Julian  wrote:
> Hi everyone,
>
> I'm relatively new to SQLite and currently I'm experimenting a little bit 
> with the SQLite database on an embedded system.
> I want to change the journal mode of a database to WAL. So I did the 
> following:
>
> rc = sqlite3_open(dbPath, );
> rc = sqlite3_exec(db, "PRAGMA journal_mode=WAL;", testCallbackPrint, 0, 
> );
> [?]
> sqlite3_close(db);
>
> Unfortunately, after these lines, the journal mode is not changed. The 
> sqlite3_exec function returns SQLITE_OK (0),
> testCallbackPrint is never called and the error message is empty.
> Also reading the value of journal mode with ?PRAGMA journal_mode;? leads to 
> the same result (rc=0, callback noch called and error message is empty).

What version of SQLite?

...
>
> Thanks.

Regards,
Smon

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

No there are no mmap support in the vfs.
So I need also -DSQLITE_DEFAULT_LOCKING_MODE=1 in my compile time options, 
right?

Recompile and retested it, but still the same behavior (also on an empty new 
db).

I am surprised that

sqlite3_exec(db, "PRAGMA journal_mode;", testCallbackPrint, 0, );

has absolutly no effect.
Should I not get at least the default journal mode as answer?



-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Clemens 
Ladisch
Sent: Donnerstag, 16. April 2015 11:23
To: sqlite-users at mailinglists.sqlite.org
Subject: Re: [sqlite] Problems with pragma journal_mode

Janke, Julian wrote:
> PRAGMA journal_mode=WAL;
>
> Unfortunately, after these lines, the journal mode is not changed.
>
> -DSQLITE_OS_OTHER=1

Do you have mmap support?

<http://www.sqlite.org/wal.html> says:
| WAL normally requires that the VFS support shared-memory primitives.
| The built-in unix and windows VFSes support this but third-party
| extension VFSes for custom operating systems might not.

But <http://www.sqlite.org/wal.html#noshm> says:
| Use of WAL Without Shared-Memory
|
| Beginning in SQLite version 3.7.4, WAL databases can be created, read,
| and written even if shared memory is unavailable as long as the
| locking_mode is set to EXCLUSIVE before the first attempted access. In
| other words, a process can interact with a WAL database without using
| shared memory if that process is guaranteed to be the only process
| accessing the database. This feature allows WAL databases to be
| created, read, and written by legacy VFSes that lack the "version 2"
| shared-memory methods xShmMap, xShmLock, xShmBarrier, and xShmUnmap on
| the sqlite3_io_methods object.


Regards,
Clemens
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Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

I use the version SQLITE_VERSION "3.8.8.3"

-Original Message-
From: sqlite-users-bounces at mailinglists.sqlite.org 
[mailto:sqlite-users-boun...@mailinglists.sqlite.org] On Behalf Of Simon Davies
Sent: Donnerstag, 16. April 2015 11:20
To: General Discussion of SQLite Database
Subject: Re: [sqlite] Problems with pragma journal_mode

On 16 April 2015 at 10:10, Janke, Julian  wrote:
> Hi everyone,
>
> I'm relatively new to SQLite and currently I'm experimenting a little bit 
> with the SQLite database on an embedded system.
> I want to change the journal mode of a database to WAL. So I did the 
> following:
>
> rc = sqlite3_open(dbPath, );
> rc = sqlite3_exec(db, "PRAGMA journal_mode=WAL;", testCallbackPrint,
> 0, ); [?] sqlite3_close(db);
>
> Unfortunately, after these lines, the journal mode is not changed. The
> sqlite3_exec function returns SQLITE_OK (0), testCallbackPrint is never 
> called and the error message is empty.
> Also reading the value of journal mode with ?PRAGMA journal_mode;? leads to 
> the same result (rc=0, callback noch called and error message is empty).

What version of SQLite?

...
>
> Thanks.

Regards,
Smon
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Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.

[sqlite] Problems with pragma journal_mode

[Janke, Julian]

Hi everyone,

I'm relatively new to SQLite and currently I'm experimenting a little bit with 
the SQLite database on an embedded system.
I want to change the journal mode of a database to WAL. So I did the following:

rc = sqlite3_open(dbPath, );
rc = sqlite3_exec(db, "PRAGMA journal_mode=WAL;", testCallbackPrint, 0, 
);
[?]
sqlite3_close(db);

Unfortunately, after these lines, the journal mode is not changed. The 
sqlite3_exec function returns SQLITE_OK (0),
testCallbackPrint is never called and the error message is empty.
Also reading the value of journal mode with ?PRAGMA journal_mode;? leads to the 
same result (rc=0, callback noch called and error message is empty).

It seems as if the pragma is ignored completely, so I tested other pragmas, 
with the same result.

So what am I doing wrong?

To compile, I use the following options
-DSQLITE_ENABLE_MEMSYS5
-DSQLITE_ENABLE_8_3_NAMES=2
-DSQLITE_THREADSAFE=0
-DSQLITE_OS_OTHER=1
-DSQLITE_ENABLE_API_ARMOR
-DSQLITE_DEFAULT_MMAP_SIZE=0
-DSQLITE_TEMP_STORE=0
-DSQLITE_DEFAULT_CACHE_SIZE=500


Thanks.





Firma: Capgemini Deutschland GmbH
Aufsichtsratsvorsitzender: Antonio Schnieder ? Gesch?ftsf?hrer: Dr. Michael 
Schulte (Sprecher) ? Jost F?rster ? Dr. Peter Lempp ? Dr. Volkmar Varnhagen

Amtsgericht Berlin-Charlottenburg, HRB 98814
This message contains information that may be privileged or confidential and is 
the property of the Capgemini Group. It is intended only for the person to whom 
it is addressed. If you are not the intended recipient, you are not authorized 
to read, print, retain, copy, disseminate, distribute, or use this message or 
any part thereof. If you receive this message in error, please notify the 
sender immediately and delete all copies of this message.