Inconsitent data

Discussion:

Inconsitent data

Koller, Georg

2005-12-16 07:08:52 UTC

Hello,

I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different applications,
running on different JVM.
I will explain the behaviour in the next few lines.

1. The mckoi DB is running as a multi-user server. A table with data
exists.
2. Application A starts up and creates a connection to the database.
This connection stays open.
3. Application B starts up and creates a connection to the database.
This connection stays open.
4. Application A reads data from a table.
5. Application B reads data from a table.

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<

Does anyone have a glue?

Thanks in advance for your help,

Georg

------------------------------------------------------------------------------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------------------------------
[mf2]

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

Nicholas Daniels

2005-12-16 07:56:23 UTC

Permalink

This sounds like you've got auto commit off in, at least, application A
- if not both. If you had to commit after your write, then both
connections should see the result in your second read.
i.e.:
Application A modifies data of table AND COMMITS.
Application A reads data from table.
Application B reads data from table.
Both applications should have the same data

Hope this helps,
Nick

Post by Koller, Georg
Hello,
I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different applications,
running on different JVM.
I will explain the behaviour in the next few lines.
1. The mckoi DB is running as a multi-user server. A table with data
exists.
2. Application A starts up and creates a connection to the database.
This connection stays open.
3. Application B starts up and creates a connection to the database.
This connection stays open.
4. Application A reads data from a table.
5. Application B reads data from a table.

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg
------------------------------------------------------------------------------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------------------------------
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

Nicholas Daniels

2005-12-16 07:59:31 UTC

Permalink

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg
------------------------------------------------------------------------------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------------------------------
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

Koller, Georg

2005-12-16 08:31:40 UTC

Permalink

Hello Nick,

thanks for your hint,

BUT I already use auto-commit off and I use commit after modifying the
table.
I want to describe a important detail of my problem description.

I stated, that the connection to the database stays open. This means,
when I reconnect application B to the database I get the correct values.

Thanks,

Georg

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Nicholas
Daniels
Sent: Friday, December 16, 2005 9:00 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This sounds like you've got auto commit off in, at least, application A
- if not both. If you had to commit after your write, then both
connections should see the result in your second read.
i.e.:
Application A modifies data of table AND COMMITS.
Application A reads data from table.
Application B reads data from table.
Both applications should have the same data

Hope this helps,
Nick

Post by Koller, Georg
Hello,
I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different

applications,

Post by Koller, Georg
running on different JVM.
I will explain the behaviour in the next few lines.
1. The mckoi DB is running as a multi-user server. A table with data
exists.
2. Application A starts up and creates a connection to the database.
This connection stays open.
3. Application B starts up and creates a connection to the database.
This connection stays open.
4. Application A reads data from a table.
5. Application B reads data from a table.

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg

------------------------------------------------------------------------
------------------------

Post by Koller, Georg
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.

------------------------------------------------------------------------
------------------------

Post by Koller, Georg
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

Andrzej Miazga

2005-12-16 10:10:02 UTC

Permalink

This is because:
"The McKoi database engine supports the strongest [transaction] isolation
level defined by the [SQL] standard - TRANSACTION_SERIALIZABLE."
This means that data read once in the transaction remain unchanged while
this transaction is open.

Greetings,
Andrzej Miazga

----- Original Message -----
From: "Koller, Georg" <***@andrew.com>
To: <***@mckoi.com>
Sent: Friday, December 16, 2005 9:31 AM
Subject: RE: Inconsitent data

Hello Nick,

thanks for your hint,

BUT I already use auto-commit off and I use commit after modifying the
table.
I want to describe a important detail of my problem description.

I stated, that the connection to the database stays open. This means,
when I reconnect application B to the database I get the correct values.

Thanks,

Georg

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Nicholas
Daniels
Sent: Friday, December 16, 2005 9:00 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This sounds like you've got auto commit off in, at least, application A
- if not both. If you had to commit after your write, then both
connections should see the result in your second read.
i.e.:
Application A modifies data of table AND COMMITS.
Application A reads data from table.
Application B reads data from table.
Both applications should have the same data

Hope this helps,
Nick

Post by Koller, Georg
Hello,
I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different

applications,

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg

------------------------------------------------------------------------
------------------------

Post by Koller, Georg
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

Koller, Georg

2005-12-20 11:10:26 UTC

Permalink

Hello Andrzej,

thanks for your answer.

I am not quiet sure, if I understand you correctly
Are you talking about a TRANSACTION or a CONNECTION.
In my case two connections are open, the transaction is closed after
modifying data.

When you are talking about a CONNECTION, this would mean, modifying a
table over one connection will have effect for other connection only,
when the first connection is closed.

When you are talking about a TRANSACTION, I have no idea. All commands
are commited, so no transactions are open.

Maybe you can clearify your mail. And maybe you have an advice to solve
my problem.

Thanks,

Georg Koller

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Andrzej
Miazga
Sent: Friday, December 16, 2005 11:10 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This is because:
"The McKoi database engine supports the strongest [transaction]
isolation
level defined by the [SQL] standard - TRANSACTION_SERIALIZABLE."
This means that data read once in the transaction remain unchanged while

this transaction is open.

Greetings,
Andrzej Miazga

----- Original Message -----
From: "Koller, Georg" <***@andrew.com>
To: <***@mckoi.com>
Sent: Friday, December 16, 2005 9:31 AM
Subject: RE: Inconsitent data

Hello Nick,

thanks for your hint,

BUT I already use auto-commit off and I use commit after modifying the
table.
I want to describe a important detail of my problem description.

I stated, that the connection to the database stays open. This means,
when I reconnect application B to the database I get the correct values.

Thanks,

Georg

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Nicholas
Daniels
Sent: Friday, December 16, 2005 9:00 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This sounds like you've got auto commit off in, at least, application A
- if not both. If you had to commit after your write, then both
connections should see the result in your second read.
i.e.:
Application A modifies data of table AND COMMITS.
Application A reads data from table.
Application B reads data from table.
Both applications should have the same data

Hope this helps,
Nick

Post by Koller, Georg
Hello,
I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different

applications,

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg

------------------------------------------------------------------------
------------------------

Post by Koller, Georg
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

Andrzej Miazga

2005-12-20 11:27:57 UTC

Permalink

Hi Georg,

Please look at the description in McKoi documentation:
http://mckoi.com/database/Transactions.html, especially at the picture in
chapter 3. In your case you should close (commit or rollback) the
transaction in application B, regardless of that this transaction doesn't
modify any data, and then you will (virtually - McKoi will do it
automatically) open the next transaction and will see the data modified by
application A. It looks a little strange, but it works this way in my
opinion.

Greetings,
Andrzej

----- Original Message -----
From: "Koller, Georg" <***@andrew.com>
To: <***@mckoi.com>
Sent: Tuesday, December 20, 2005 12:10 PM
Subject: RE: Inconsitent data

Hello Andrzej,

thanks for your answer.

I am not quiet sure, if I understand you correctly
Are you talking about a TRANSACTION or a CONNECTION.
In my case two connections are open, the transaction is closed after
modifying data.

When you are talking about a CONNECTION, this would mean, modifying a
table over one connection will have effect for other connection only,
when the first connection is closed.

When you are talking about a TRANSACTION, I have no idea. All commands
are commited, so no transactions are open.

Maybe you can clearify your mail. And maybe you have an advice to solve
my problem.

Thanks,

Georg Koller

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Andrzej
Miazga
Sent: Friday, December 16, 2005 11:10 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This is because:
"The McKoi database engine supports the strongest [transaction]
isolation
level defined by the [SQL] standard - TRANSACTION_SERIALIZABLE."
This means that data read once in the transaction remain unchanged while

this transaction is open.

Greetings,
Andrzej Miazga

----- Original Message -----
From: "Koller, Georg" <***@andrew.com>
To: <***@mckoi.com>
Sent: Friday, December 16, 2005 9:31 AM
Subject: RE: Inconsitent data

Hello Nick,

thanks for your hint,

BUT I already use auto-commit off and I use commit after modifying the
table.
I want to describe a important detail of my problem description.

I stated, that the connection to the database stays open. This means,
when I reconnect application B to the database I get the correct values.

Thanks,

Georg

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Nicholas
Daniels
Sent: Friday, December 16, 2005 9:00 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This sounds like you've got auto commit off in, at least, application A
- if not both. If you had to commit after your write, then both
connections should see the result in your second read.
i.e.:
Application A modifies data of table AND COMMITS.
Application A reads data from table.
Application B reads data from table.
Both applications should have the same data

Hope this helps,
Nick

Post by Koller, Georg
Hello,
I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different

applications,

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg

------------------------------------------------------------------------
------------------------

Post by Koller, Georg
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

------------------------------------------------------------------------
------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------
------------------------
[mf2]

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

------------------------------------------------------------------------------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------------------------------
[mf2]

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

Koller, Georg

2005-12-20 12:17:39 UTC

Permalink

Hello Andrzej,

thanks a lot for your help.
My mistake was, I didn't commit reads from database.

Bye,
Georg

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Andrzej
Miazga
Sent: Tuesday, December 20, 2005 12:28 PM
To: ***@mckoi.com
Subject: Re: Inconsitent data

Hi Georg,

Please look at the description in McKoi documentation:
http://mckoi.com/database/Transactions.html, especially at the picture
in
chapter 3. In your case you should close (commit or rollback) the
transaction in application B, regardless of that this transaction
doesn't
modify any data, and then you will (virtually - McKoi will do it
automatically) open the next transaction and will see the data modified
by
application A. It looks a little strange, but it works this way in my
opinion.

Greetings,
Andrzej

----- Original Message -----
From: "Koller, Georg" <***@andrew.com>
To: <***@mckoi.com>
Sent: Tuesday, December 20, 2005 12:10 PM
Subject: RE: Inconsitent data

Hello Andrzej,

thanks for your answer.

I am not quiet sure, if I understand you correctly
Are you talking about a TRANSACTION or a CONNECTION.
In my case two connections are open, the transaction is closed after
modifying data.

When you are talking about a CONNECTION, this would mean, modifying a
table over one connection will have effect for other connection only,
when the first connection is closed.

When you are talking about a TRANSACTION, I have no idea. All commands
are commited, so no transactions are open.

Maybe you can clearify your mail. And maybe you have an advice to solve
my problem.

Thanks,

Georg Koller

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Andrzej
Miazga
Sent: Friday, December 16, 2005 11:10 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This is because:
"The McKoi database engine supports the strongest [transaction]
isolation
level defined by the [SQL] standard - TRANSACTION_SERIALIZABLE."
This means that data read once in the transaction remain unchanged while

this transaction is open.

Greetings,
Andrzej Miazga

----- Original Message -----
From: "Koller, Georg" <***@andrew.com>
To: <***@mckoi.com>
Sent: Friday, December 16, 2005 9:31 AM
Subject: RE: Inconsitent data

Hello Nick,

thanks for your hint,

BUT I already use auto-commit off and I use commit after modifying the
table.
I want to describe a important detail of my problem description.

I stated, that the connection to the database stays open. This means,
when I reconnect application B to the database I get the correct values.

Thanks,

Georg

-----Original Message-----
From: ***@mckoi.com [mailto:***@mckoi.com] On Behalf Of Nicholas
Daniels
Sent: Friday, December 16, 2005 9:00 AM
To: ***@mckoi.com
Subject: Re: Inconsitent data

This sounds like you've got auto commit off in, at least, application A
- if not both. If you had to commit after your write, then both
connections should see the result in your second read.
i.e.:
Application A modifies data of table AND COMMITS.
Application A reads data from table.
Application B reads data from table.
Both applications should have the same data

Hope this helps,
Nick

Post by Koller, Georg
Hello,
I have a problem with inconstent data.
Am accessing the Mckoi (1.0.3) database from two different

applications,

Both applications get the same values. <<<

6. Application A modifies data of table.
7. Application A reads data from table.
8. Application B reads data from table.

Application A gets the new data, Application B gets the old data.

<<<
Does anyone have a glue?
Thanks in advance for your help,
Georg

------------------------------------------------------------------------
------------------------

Post by Koller, Georg
[mf2]
---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

------------------------------------------------------------------------
------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------
------------------------
[mf2]

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

------------------------------------------------------------------------
------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------
------------------------
[mf2]

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com

------------------------------------------------------------------------------------------------
This message is for the designated recipient only and may
contain privileged, proprietary, or otherwise private information.
If you have received it in error, please notify the sender
immediately and delete the original. Any unauthorized use of
this email is prohibited.
------------------------------------------------------------------------------------------------
[mf2]

---------------------------------------------------------------
Mckoi SQL Database mailing list http://www.mckoi.com/database/
To unsubscribe, send a message to mckoidb-***@mckoi.com