A Twitter follower recently asked for more information on user-defined types in the PL/SQL language, and I figured the best way to answer is to offer up this blog post. PL/SQL is a strongly-typed language . Before you can work with a variable or constant, it must be declared with a type (yes, PL/SQL also supports lots of implicit conversions from one type to another, but still, everything must be declared with a type). PL/SQL offers a wide array of pre-defined data types , both in the language natively (such as VARCHAR2, PLS_INTEGER, BOOLEAN, etc.) and in a variety of supplied packages (e.g., the NUMBER_TABLE collection type in the DBMS_SQL package). Data types in PL/SQL can be scalars, such as strings and numbers, or composite (consisting of one or more scalars), such as record types, collection types and object types. You can't really declare your own "user-defined" scalars, though you can define subtypes from those scalars, which can be very helpful from the p...
The commit was within an autonomous transaction.
ReplyDeleteAutonomous Transaction!
ReplyDeletecommit write nowait/batch?
ReplyDeleteAutonomous Transaction :allows you to leave the context of the calling transaction, perform an independent transaction, and return to the calling transaction without affecting it's state.Hence the uncommitted changes in the users session are still significant.
ReplyDeleteAutonomous transaction! Love the brain teaser!!
ReplyDeleteJust few untested random use-cases in a hurry. Feel free to correct.
ReplyDelete1. Dirty data is in bulk collected collections. Processing commits in loop.
2. View with instead of trigger. Trigger only uses partial data to update.
3. Part of dirty data is written to a external table on really slow IO device.
4. Distributed transaction. Part of dirty data has to be updated on some other DB.
5. Call to external service from API with part of dirty data.
6. Trigger on table allows selective data to update?
It all depends where in the process chain the commit was executed, if there were any dml statements after it, and if any rollback (to savepoint) was executed...
ReplyDeleteAnd here are some thoughts offered up on LinkedIn:
ReplyDelete* Is the commit statement outside the procedure? It so, it may be out of scope. Is there a rollback somewhere in the procedure or function?
* The procedure having COMMIT might have executed with autonomously. So the user changes outside that procedure are still in process and not yet committed.
And now my answer: definitely, the answer in my mind is that the COMMIT statement was executed within an autonomous transaction subprogram.
ReplyDeleteIf you include
PRAGMA AUTONOMOUS_TRANSACTION;
in the declaration section of your procedure or function, then a COMMIT in that subprogram will commit only those changes made in the scope of that subprogram.
Other outstanding changes in my session will NOT be committed.
Now as to your comments:
@stanley, I'd love to hear more explanation about some of your items, as they are outside my area of expertise. I am not sure if a distributed xaction applies here, since I reference the "user's session".
@john, certainly any DML statements executed after the commit would be uncommitted. ROLLBACK TO before the commit would remove outstanding changes. After the commit? Well, the teaser has to do with state of session right after the commit (implied: before other actions take place).
Thanks for participating!