optimizer

Oracle 10 optimizer from RULE to COST: why?

Oracle decided to dismiss the rule-based optimizer from version 10g, leaving the cost-based one as the only choice. I think that a rule-based optimizer has the unvaluable positive side of being always predictable. I've seen instead Oracle 10g changing execution plans from night to day, leading to turtle-like performances. Which could be ...

Is it possible to write a decent java optimizer if information is lost in the translation to bytecode?

It occurred to me that when you write a C program, the compiler knows the source and destination platform (for lack of a better term) and can optimize to the machine it is building code for. But in java the best the compiler can do is optimize to the bytecode, which may be great, but there's still a layer in the jvm that has to interpret...

Question about c# optimizer.

If I write: SomeType simpleName = classWithLongName.otherLongName; And then use "simpleName" instead of "classWithLongName.otherLongName", will this change the program in any way (for instance performance wise)? What does the compiler do with this? Does it copy+paste "classWithLongName.otherLongName", everywhere I use "simpleName". ...

How does compiler optimize virtual methods implemented by a sealed class

I'm wondering how the following code is optimized. Specifically concerning virtual and direct calls. I have commented on how I think everything is optimized but those are just guesses. public abstract class Super { public abstract void Foo(); public void FooUser() { Foo(); } } public class Child1 : Super { ...

Is there a Java bytecode optimizer that removes useless gotos?

Problem: I have a method that compiles to over 8000 bytes of Java bytecode. HotSpot has a magic limit that makes the JIT not kick in for methods that exceed 8000 bytes. (Yes, it is reasonable to have a huge method. This is a tokenizer loop.) The method is in a library and I don't want to require users of the library to have to configure ...

How to increase Oracle CBO cost estimation for hash joins, group by's and order by's without hints

It seems that on some of the servers that we have, the cost of hash joins, group by's and order by's is too low compared to the actual cost. I.e. often execution plans with index range scans outperform the former, but on explain plan the cost shows up as higher. Some further notes: I already set *optimizer_index_cost_adj* to 20 and it...

What's the easiest way to expose a SQL interface to my application?

I'm working on an application which stores data in tables, similar to an RDBMS. I'm looking for a way to let my users query this data using SQL. Ideally, I'd like to do this without having to implement my own SQL parser, query optimizer, etc. So far, ripping parts out of something like Apache Derby is looking like the best option, but...

HTML online minimizer/compressor?

Does anyone know of a good online generator to take the source code of an HTML page and compress/minimize the entire page. Meaning, compress/minimize all embedded CSS, JavScript and obviously the HTML of that web page while also removing unneeded HTML/CSS/JavaScript comments, spaces, tabs, etc? ...

Oracle Anti-Join Execution plan question

We have two tables like so: Event id type ... a bunch of other columns ProcessedEvent event_id process There are indexes defined for Event(id) (PK) ProcessedEvent (event_id, process) The first represents events in an application. The second represents the fact that a certain event got processes by a certain...

Can I get a regular page to redirect page in a subdirectory?

I want to be able to use a clean url to test in google optimizer.... can i create a file called geolocationtest.php so that http://neighborrow.com/geolocationtest.php will redirect to http://neighborrow.com/v2/controllers/ and eliminate the directory problem that google doesnt like? ...

Google Website Optimizer not tracking conversions

In a nutshell my split tests aren't tracking conversions at all. My A/B pages are on http://www.mydomain.com, and my conversion page is the last stage of my shopping cart on https://secure.mydomain.com. I thought the most concise way of explaining this would be to post my page source code: http://pastebin.com/ru7dCDqD To summarize, ...

GCC, -O2, and bitfields - is this a bug or a feature?

Today I discovered alarming behavior when experimenting with bit fields. For the sake of discussion and simplicity, here's an example program: #include <stdio.h> struct Node { int a:16 __attribute__ ((packed)); int b:16 __attribute__ ((packed)); unsigned int c:27 __attribute__ ((packed)); unsigned int d:3 __attribute__ ((packe...

not able to play my fav. games

Hi Guys, Plz tell is there any tool that increases my games performance..as they are slowing a bit...i use to play games like. NFS Carbon & Most Wanted, Counter Strike..Don't know what is wrong..!! I have done a cleanup and defrag hoping that would speed up my computer.But it did not help much.. PC's Config.. OS:Win Vista, 2 GB RAM, M...

Looking for a CSS optimizer (php script or online services)

Hi, I'm looking for a css optimizer. It should be a php script so I can install on my host or online services. I need some feature like below. Any recommended? from: margin-top:5px; margin-right:10px; margin-bottom:8px; margin-left:2px; to: => margin:5px 10px 8px 2px; from: -moz-border-radius-topleft: 5px; to: => -moz-border-r...

Query parser and optimizer for OSGi/LDAP filters/queries?

I'm looking for a query parser and optimizer that can work with OSGi filter conditions, which are based on LDAP query syntax. Preferably something implemented in Java, but a different implementation (even web based) would be good too. My main use case is to feed it queries that maybe can be simplified. ...

Is ASP.NET (webforms) Incompatible with Google Website Optimizer Multivariate Testing?

I've been stuggling all morning trying to get a multivariate test going in google website optimizer. I've copy and pasted the header/footer code into the pages, and setup a basic page section just to see that everything is working. When I try to validate the code its failing saying "No sections detected on test page TestSectionName -...