On An Average Day


"There are other advantages," continued the child. "For instance, if one rat were cornered by nine cats,
on the average, each cat would be ten percent rat and the rat would be ninety percent cat. If you happened
to be a rat, you can see how much nicer it would make things."
-- Norton Juster, The Phantom Tollbooth

Recently an interesting question appeared on “Ask Tom” with regard to the ‘average’ between two dates. (more...)

Size Does Matter


"You see, to tall men I'm a midget, and to short men I'm a giant;
to the skinny ones I'm a fat man, and to the fat ones I'm a thin man."
-- Norton Juster, The Phantom Tollbooth

Someone in one of the Oracle forums asked the following question:


How to estimate datafile size of tablespace when it is almost full? Could someone please explain?

which is ambiguous to say the least, since no (more...)

He’s Making A List


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

Recently a tweet by Chris Saxon (@chrisrsaxon) with respect to SQL, the language and implementation, started a list of contributions which should cause people to think a bit differently about how the language works and how queries should be structured. The list, found here, is by no stretch of the imagination (more...)

Examining The Remains


"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...)

“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...)