Synchronization of multiple clients

[Stephan Keil]

Hi all,

I've got a question concerning synchronization of multiple database clients.
Consider a database, accessed by two clients. Is it guarantted, that if
client 1 succefully commits a transaction, client 2 _instantly_ sees the
changes made by client 1?

thx and regards,

Stephan

P.S..: For MS Jet databases I know there _is_ a delay between writing data
to the database and being able to read this updated value from another
connection,
so the question refers to "real" DBMs (esp. SQL Server) only ;)

[Simon Hayes]

"Stephan Keil" <St**********@gmx.de> wrote in message
news:2r*************@uni-berlin.de...

Hi all,

I've got a question concerning synchronization of multiple database
clients.
Consider a database, accessed by two clients. Is it guarantted, that if
client 1 succefully commits a transaction, client 2 _instantly_ sees the
changes made by client 1?

thx and regards,

Stephan

P.S..: For MS Jet databases I know there _is_ a delay between writing data
to the database and being able to read this updated value from another
connection,
so the question refers to "real" DBMs (esp. SQL Server) only ;)

Yes - the data on disk may not be modified immediately, but the data in the
buffer cache is, and MSSQL can satisfy other client requests directly from
the cache. You might also want to look at isolation levels, as they affect
exactly how consistent the client's view of the data within a transaction
is. See "I/O Architecture" and "SET TRANSACTION ISOLATION LEVEL" in Books
Online.

Simon