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Editorial Team
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Asked: 2026-05-31T09:47:02+00:00

I have a process wherein a program running in an application server must access

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I have a process wherein a program running in an application server must access a table in an Oracle database server whenever at least one row exists in this table. Each row of data relates to a client requesting some number crunching performed by the program. The program can only perform this number crunching serially (that is, for one client at a time rather than multiple clients in parallel).

Thus, the program needs to be informed of when data is available in the database for it to process. I could either

  1. have the program poll the database, or
  2. have the database trigger the program.

QUESTION 1: Is there any conventional wisdom why one approach might be better than the other?

QUESTION 2: I wonder if programs have any issues “running” for months at a time (would any processes in the server stop or disrupt the program from running? — if so I don’t know how I’d learn there was a problem unless from angry customers). Anyone have experience running programs on a server for a long time without issues? Or, if the server does crash, is there a way to auto-start a (i.e. C language executable) program on it after the server re-boots, thus not requiring a human to start it specifically?

Any advice appreciated.

UPDATE 1: Client is waiting for results, but a couple seconds additional delay (from polling) isn’t a deal breaker.

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1 Answer

  1. Editorial Team

    1) have the program poll the database, since you don’t want your database to be able to start host programs (because you’d have to make sure that only “your” program can be started this way).

    The classic (and most convenient IMO) way for doing this in Oracle would be through the DBMS_ALERT package.

    The first program would signal an alert with a certain name, passing an optional message. A second program which registered for the alert would wait and receive it immediatly after the first program commits. A rollback of the first program would cancel the alert.

    Of cause you can have many sessions signaling and waiting for alerts. However, an alert is a serialization device, so if one program signaled an alert, other programs signaling the same alert name will be blocked until the first one commits or rolls back.

    Table DBMS_ALERT_INFO contains all the sessions which have registered for an alert. You can use this to check if the alert-processing is alive.

    2) autostarting or background execution depends on your host platform and OS. In Windows you can use SRVANY.EXE to run any executable as a service.

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