SQL Anywhere Mobile - Concurrncy question

Author

Concurrncy question

Dimitris Karistinos

2005-06-15, 7:24 am

Hello group,

I have a new question regarding Mobilink! I was reading some things
regarding Concurrency but they are not very clear to me....

In fact I was reading the following link
http://www.ianywhere.com/developer/...n9/00000083.htm

So here are my questions
1. When a synchronization is taking place, is it possible for someone using
another application to update the consolidated database and specifically
tables that are taking part in the synchronization?

2. Using the -d option it says that "When this option is specified, any
connection with locks that would interfere with synchronization are dropped
by the database so that synchronization can proceed"

Which connection does it mean? Connections made to the consolidated database
or the remote one?

Kind Regards
Dimitris Karistinos

Reg Domaratzki \(iAnywhere Solutions\)

2005-06-15, 9:24 am

The section you were reading was dealing with the remote database and
dbmlsync, so nothing in that section refers to the consolidated database.
You use the LockTables extended option to determine whether tables are
exclusively locked ON THE REMOTE during a synchronization. If you choose to
not lock the tables, the download may fail, so you need to choose between
being able to modify tables during a synchronization versus the possibility
of not getting the download stream if you modify data during the
synchronization that is changed while applying the download stream.

--
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"Dimitris Karistinos" <dkaris@relational.gr> wrote in message
news:42afee06@forums
-1-dub...
> Hello group,
>
> I have a new question regarding Mobilink! I was reading some things
> regarding Concurrency but they are not very clear to me....
>
> In fact I was reading the following link
>
http://www.ianywhere.com/developer/...n9/00000083.htm
>
>
> So here are my questions
> 1. When a synchronization is taking place, is it possible for someone
using

> another application to update the consolidated database and specifically
> tables that are taking part in the synchronization?
>
> 2. Using the -d option it says that "When this option is specified, any
> connection with locks that would interfere with synchronization are
dropped
> by the database so that synchronization can proceed"
>
> Which connection does it mean? Connections made to the consolidated
database
> or the remote one?
>
> Kind Regards
> Dimitris Karistinos
>
>

Breck Carter [TeamSybase]

2005-06-15, 9:24 am

On 15 Jun 2005 01:59:50 -0700, "Dimitris Karistinos"
<dkaris@relational.gr> wrote:

>Hello group,
>
>I have a new question regarding Mobilink! I was reading some things
>regarding Concurrency but they are not very clear to me....
>
>In fact I was reading the following link
>http://www.ianywhere.com/developer/...n9/00000083.htm
>
>
>So here are my questions
>1. When a synchronization is taking place, is it possible for someone using
>another application to update the consolidated database and specifically
>tables that are taking part in the synchronization?

Yes. The MobiLink server is just another application, subject to the
same rules about transactions, locks, blocks and isolation levels as
any other application. In practice, however, concurrency issues are
more common on the remote database than the consolidated.

>2. Using the -d option it says that "When this option is specified, any
>connection with locks that would interfere with synchronization are dropped
>by the database so that synchronization can proceed"
>
>Which connection does it mean? Connections made to the consolidated database
>or the remote one?

That is an option of the MobiLink remote client dbmlsync.exe, so it
applies to the remote database.

Breck

>Kind Regards
>Dimitris Karistinos
>

--
SQL Anywhere Studio 9 Developer's Guide
Buy the book: http://www.amazon.com/exec/obidos/A...7/risingroad-20
bcarter@risingroad.com
RisingRoad SQL Anywhere and MobiLink Professional Services
www.risingroad.com

Dimitris Karistinos

2005-06-16, 7:24 am

Thank you all for your responses....

Regards
Dimitris Karistinos
"Breck Carter [TeamSybase]" < NOSPAM__bcarter@risi
ngroad.com> wrote in
message news:vqb0b19g7skuiml
b5frmjd8v0v4ud18l3l@
4ax.com...
> On 15 Jun 2005 01:59:50 -0700, "Dimitris Karistinos"
> <dkaris@relational.gr> wrote:
>
>
> Yes. The MobiLink server is just another application, subject to the
> same rules about transactions, locks, blocks and isolation levels as
> any other application. In practice, however, concurrency issues are
> more common on the remote database than the consolidated.
>
>
> That is an option of the MobiLink remote client dbmlsync.exe, so it
> applies to the remote database.
>
> Breck
>
>
>
> --
> SQL Anywhere Studio 9 Developer's Guide
> Buy the book:
> http://www.amazon.com/exec/obidos/A...7/risingroad-20
> bcarter@risingroad.com
> RisingRoad SQL Anywhere and MobiLink Professional Services
> www.risingroad.com

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