What are all the possible reasons for loosing permanaent database-conections?
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Posted By:   max_laenzlinger
Posted On:   Saturday, November 24, 2001 12:00 AM

Hello,

I loose sometimes database connections from the connection-pool of my web-application.
What are the possible reasons for that? (I know already: connections are lost f.i. when the database-server is rebootet and the applicationserver is not able to reconnect automaticly)

Are there reasons in network-technology/complexity which cannot be avoided? Does the network size matter?

Is programmatic regularly reallocating of the pool in a way a good advise for all web-applications?

Thanks all of your input & have a nice weekend
Max

Re: What are all the possible reasons for loosing permanaent database-conections?

Posted By:   Bernie_Acs  
Posted On:   Saturday, November 24, 2001 12:24 PM

In a connection-pool the min-number of connections normally are left open to the DB, in some case the DB may have session settings that limit the amount of idle time a session may accumilate which could cause a valid but idle session to become disconnected. Certainly network size and load can play role in the amount of time that is required to make a connection or to perform a given transaction. One could provide for unexpected disconnection by implimenting mechanics for connection fall-over in the event of failure.

A more important point of attack is to insure that both the app-server and the DB parameters allow for generious time out values for idle sessions and connect times to accomidate the runtime environment and the various levels of load during the full cycle of server operations.

You may consider using some time based listener class which could exercise idle connections regularly to help insure they remain valid during normally idle periods, this same process could also play a role in helping to determine the cause of bad connections in the pool by assisting in determining exactly when a connection set became bad. It is important to reckonize that each of the presistant min connections require this exercise to prevent them from becoming stale.
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