“It Doesn’t Work”


“Since you got here by not thinking, it seems reasonable to expect that, in order to get out, you must start thinking.”
— Norton Juster, The Phantom Tollbooth

The Devil is in the details, however, in support forums and newsgroups, the Devil is just as present when the details are either sketchy or non-existent. Volunteers in such forums and newsgroups quite often hear the dreaded words “it doesn’t work”, followed by … nothing. No (more...)

“It’s … MUTATING!!!!”


“The most important reason for going from one place to another is to see what's in between.” 
― Norton Juster, The Phantom Tollbooth   

The mutating table error (ORA-04091) thrown by Oracle can be a familiar sight throughout a DBA’s career, along with the usual question of ‘Why?’. The error itself is not difficult to understand nor is it hazardous to the table data. Let’s look at why the error is thrown, why it’s (more...)

Repeat After Me


“every time you decide something without having a good reason, you jump to Conclusions whether you like it or not.” 
-- Norton Juster, The Phantom Tollbooth

In an Oracle forum recently the following question was posted:


I have a request for 3 indices as shown below. Does the 1st index suffice for 2 and 3?  Do I need all 3?
 
    CREATE INDEX IDX_ATM_EM_EFF_VER_CURRENT_DEL ON ATM_xxx_SALARY
    (EMPLOYEE_KEY, EFFECTIVE_DT, SALARY_VERSION_NUMBER, IS_CURRENT, IS_DELETED);

    CREATE INDEX IDX_ATM_EM_VER_CURRENT ON  (more...)

“That Ain’t Right”


"Is everyone who lives in Ignorance like you?" asked Milo.
"Much worse," he said longingly. "But I don't live here. I'm from a place very far away called Context." 
-- Norton Juster, The Phantom Tollbooth 

Dates are, well, dates. They are not strings, they are not numbers, they are dates and to handle them properly the correct data type needs to be used. I can’t count how many times I’ve seen dates stored (more...)

Heap Of Trouble


"But I suppose there's a lot to see everywhere, if only you keep your eyes open."
-- Norton Juster, The Phantom Tollbooth 

Oracle Support recently updated what I call a ‘blast from the past’; it involves a subpool memory leak in Oracle 11.2.0.1 and shared cursors. Originally submitted in 2010 this issue was updated the end of last year to reflect the status of ‘Fixed in Product Version 12.1’. There (more...)

“Say What?!?!?”


"The only thing you can do easily is be wrong, and that's hardly worth the effort." 
Norton Juster, The Phantom Tollbooth

Oracle can lie to you. Not like a disreputable uwed-car salesman but more like the ‘little white lie’ sometimes told in order to hide less-than-desirable parts of the truth. And it’s not Oracle, really, it’s the optimizer and it does it by reporting query plans that may not accurtely report the execution path. (more...)

Export-Import Business


"Don't you know anything at all about numbers?"

"Well, I don't think they're very important," snapped Milo, too embarrassed to admit the truth.

"NOT IMPORTANT!" roared the Dodecahedron, turning red with fury. "Could you have tea for two without
the two -- or three blind mice without the three? Would there be four corners of the earth if there
weren't a four? And how would you sail the seven seas without a seven? (more...)

You’re On A Roll(back)


"I know one thing for certain; it is much harder to tell whether you are lost than whether 
you were lost, for, on many occasions, where you are going is exactly where you are. On 
the other hand, if you often find that where you've been is not at all where you should have 
gone, and, since it's much more difficult to find your way back from someplace you've never 
left, I suggest you go  (more...)

Results, What Results?


"For instance," said the boy again, "if Christmas trees were people and people were Christmas trees,
we'd all be chopped down, put up in the living room, and covered in tinsel, while the trees opened our presents."
"What does that have to do with it?" asked Milo.
"Nothing at all," he answered, "but it's an interesting possibility, don't you think?"
Norton Juster, The Phantom Tollbooth 

Oracle offers a results cache in the (more...)

Hakan You Do That?


"Everyone understands numbers. No matter what language you speak,
they always mean the same thing. A seven is a seven anywhere in the world." 
Norton Juster, The Phantom Tollbooth 

An interesting problem submitted to Oracle Support involves a possibly little-known aspect of a table called the Hakan Factor. The problem description, in brief, states that the Hakan Factor isn’t preserved for a partitioned table when a single partition is compressed. Why is this a (more...)