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Java Forum / Databases / June 2003testing for database availability
What is the best way to test for the db server to be running? I have created a connection and am executing a simple statement. Thanks, Gary > What is the best way to test for the db server to be running? I have > created a connection and am executing a simple statement. The answer: Execute the simple statement. If it works, the DBMS is running. If it fails, depending on what exception you get, the DBMS may not be running. In fact, there is no way for a client (including the driver) to know if the connection to the server is good, except to try to use it. Furthermore, as soon as the result comes back, we only know that the connection *was* good. The very next use may fail. Thus your code will always have to be able to handle the situation of a broken connection anywhere in your code. Joe Weinstein at BEA > Thanks, > > Gary I just fetch a little bit of the metadata, e.g. the DriverName or the DB-Version. As this needs a working connection to the DB, I know its fine. Regards Fredy >What is the best way to test for the db server to be running? I have >created a connection and am executing a simple statement. > >Thanks, > >Gary > I just fetch a little bit of the metadata, e.g. the DriverName or the > DB-Version. > As this needs a working connection to the DB, I know its fine. Beware that some metadata calls, such as DriverName are usually hardwired into the driver itself (no dbms contact needed), and others, like the db version may need dbms contact once per connection, and the driver may cache the answer and avoid the dbms roundtrip after that. The most reliable is one that make the DBMS do a minimm of parsing but does ask the DBMS something where the answer could be different each time you ask. > Regards > [quoted text clipped - 6 lines] > > > >Gary Fredy, Meta data sometimes gets cached by the driver. The best way is to issue a simple select statement like: select 'Test' from AnySmallTable where 1 = 0 MB > I just fetch a little bit of the metadata, e.g. the DriverName or the > DB-Version. [quoted text clipped - 9 lines] >> >> Gary Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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