Comments on: So what’s Oracle’s MPP-aware optimizer and query execution plan story?

By: Oracle Database Machine and Exadata pricing: Part 2 | DBMS2 -- DataBase Management System Services

Tue, 30 Sep 2008 07:06:01 +0000

[...] look like good things to have no matter what. For example, as per a comment thread last week, what what Oracle packages as its no-added-charge optimizer is somewhat questionable, and many sites need a third-party product and/or Oracle’s extra-charge Tuning Pack to fill [...]

By: Curt Monash

Curt Monash — Mon, 29 Sep 2008 21:12:41 +0000

I was talking with an Oracle development manager on the DSS side, and he spoke favorably of Oracle’s SQL Tuning chargeable option.

CAM

By: David Aldridge

David Aldridge — Mon, 29 Sep 2008 20:50:47 +0000

“there is at least one product you can buy that takes in an Oracle query, and puts out a new Oracle query with the same semantics, but which executes much faster” …

That would also be what the Oracle cost-based optimizer does in its query transformation step, wouldn’t it? Star transformations, unnesting subqeries, transitive closure etc?

With regard to getting queries right for Oracle, there may be some truth in Daniel’s statement for complex OLTP queries, but BI/DW queries are generally not rocket science — that is after all practically the raison d’etre for the star schema. So I question the relevance here.

By: Curt Monash

Curt Monash — Fri, 26 Sep 2008 23:09:32 +0000

Fair enough, Jay. I was just curious as to what Dan thought was the one and only such product — but upon rereading, he didn’t assert there was only one. Oops!

Thanks,

CAM

By: Jay Jakosky

Jay Jakosky — Fri, 26 Sep 2008 20:21:32 +0000

I don’t know which one Dan refers to but they’re pretty common. There’s one inside Toad that parses the query, creates candidates and asks the Oracle optimizer to rate those candidates. You can then make a selection and execute the queries to confirm Oracle’s estimates.

I used the product briefly but regularly and it did an excellent job. And this is just an extra-value component to an already popular product. I can only imagine the effectiveness of other solutions.

By: Curt Monash

Curt Monash — Fri, 26 Sep 2008 11:16:23 +0000

Dan,

Which product are you referring to?

CAM

By: Daniel Weinreb

Daniel Weinreb — Fri, 26 Sep 2008 10:13:38 +0000

Pardon me, when you say “Oracle’s query optimizer”, are you referring to the one in Oracle Database, the flagship RDBMS product? If so, I beg to differ. It is very, very hard to write queries for Oracle that will produce good performance. My own experience and that of my DB-savvy friends is that if you want your queries written right, you have to get a super-experienced Oracle wizard. I only know one such person, although I’m sure there are many more. But they cost a lot (as consultants).

Also, there is at least one product you can buy that takes in an Oracle query, and puts out a new Oracle query with the same semantics, but which executes much faster: a third-party query optimizer! (That’s almost as stupid as those third-party uninstall utilities for Windows.)

By: gsalem

gsalem — Thu, 25 Sep 2008 22:08:34 +0000

Curt,
you’re terribly mistaken: If you have RAC, you can make all your nodes work on the query, and all of them profit from exadata: they can scan/join/aggregate data and send it back to the node that your client is connected to.