Possible index combinations in 2D array - more Math Question than LabView???

Hi All,
I am struggling with this problem:
I have a 2D array
50 62 73 82 91 96 100
43 78 146 186 230 255
0.25 2 6 12 20
5 50 500 2000 8000
5 50 500 2000 8000

As a general rule of thumb, given a 2-D array with a set number X and Y the unique number of index combinations will be simply X * Y. So, for example, a 5 x 5 array will have 25 unique combinations. [1][1], [1][2], [1][3], ... , [4][5], [5][5].

Similar Messages

Possible index combinations in 2D array - more Math Question than LabView???

Hi All,
I accidently submitted the first post.. please disregard the previous one.
I am struggling with this problem. Please HELP!!!
I have an array of numbers:
Set1 50     62    73    82       91     96   100
Set2 43     78    146 186    230   255
Set3 0.25  2      6     12       20
Set4 5       50    500   2000 8000
Set5 5       50    500   2000  8000
I need to create all possible combinations for Set1 through Set5.
Example:
{50, 43, 0.25, 5, 5}
{50, 43, 0.25, 5, 50}
{50, 43, 0.25, 5, 500}
{50, 43, 0.25, 5, 2000}
{50, 43, 0.25, 5, 8000}
{50, 43, 0.25, 5, 5}
{50, 43, 0.25, 50, 5}
{50, 43, 0.25, 500, 5}
{50, 43, 0.25, 2000, 5}
{50, 43, 0.25, 8000, 5}
{50, 43, 0.25, 5, 5}
{50, 43, 2, 5, 5}
{50, 43, 6, 5, 5}
{50, 43, 12, 5, 5}
{50, 43, 20, 5, 5}
and so on....
I just can't figure out how to loop this through to go through all possible combinations of the 5 sets. (
Looking forward to your suggestions and help.
Thanks,
Mim
Message Edited by Mim on 11-17-2005 11:26 AM

You have to have 5 nested loops.
Let's call your COLUMNS A-E and your ROWS 0-4:
A0 B0 C0 D0 E0
A1 B1 C1 D1 E1
A2 B2 C2 D2 E2
A3 B3 C3 D3 E3
A4 B4 C4 D4 E5
Extract all the COLUMNS.
Take COLUMN A and autoindex it on the first (outside) loop:
For i = 0 to 4
Ax = A[i]
Pass Column B THROUGH the first FOR loop and autoindex it on the second loop:
For i = 0 to 4
Bx = B[i] // autoindexing will do this for you
Pass Column C THROUGH the first and second FOR loop and autoindex it on the third loop:
For i = 0 to 4
Cx = C[i] // autoindexing will do this for you
and so on:
For i = 0 to 4
Dx = D[i] // autoindexing will do this for you
For i = 0 to 4
Ex = E[i] // autoindexing will do this for you
Assemble Ax, Bx, Cx, Dx and Ex into a set and do with it what you want.
Just do five nested loops and remember to autoindex A on the outside loop, B on the 2nd, C on the 3rd, D on the 4th, and E on the inside loop.
I think you will get 5^5 combinations.Message Edited by CoastalMaineBird on 11-17-2005 10:44 AM
Message Edited by CoastalMaineBird on 11-17-2005 10:45 AM
Steve Bird
Culverson Software - Elegant software that is a pleasure to use.
Culverson.com
Blog for (mostly LabVIEW) programmers: Tips And Tricks

How do i create arrays more efficiently

how do i create arrays more efficiently?... need to insert data into an array every loop iteration. I am using the insert into array function and shift registers. I have been told this is inefficient... and they are right because I can make the program stop and it gives me the error that labview does not have enough memory. A coworker said to avoid shift registers and investigate property nodes... i am new at this and don't know what this is exactly.. is there a tutorial on efficent data handling.. or examples that would be usefull?

tbob wrote:
Mark is absolutely correct. Indexing will take a lot of memory and a lot of time when the array gets large. Indexing is great for small arrays though. With indexing, the first loop iteration will create an array of size 1. On the next loop, the array has to be copied, re-dimensionedcto size 2, old data copied to new array, and new data inserted at end. You can see how this will become a monster with an array size of 10,000. With pre-allocation, there is no re-dimensioning and no copying. Array elements are simple replaced. And yes you do have to know the upper limit to use pre-allocation. Kudos to Mark for pointing out the facts.
A bit of a clarification is needed. Folks from NI told me that LabVIEW tries to be smart when autoindexing. When they allocate the memory the initial chunk of memory it is larger than a single element. So you don't necessarily get a copy and allocation every iteration. They may have improved the optimization to preallocate the complete array if the size is already known (a constant wired to the loop count). However, they would have no way of doing this if the number of iterations is not known ahead of time.
Mark Yedinak
"Does anyone know where the love of God goes when the waves turn the minutes to hours?"
Wreck of the Edmund Fitzgerald - Gordon Lightfoot

Is it possible to Create a Long Text Field (more than 255 Char Long)?

Is it possible to Create a Long Text Field (more than 255 Char Long) as like Description field in Service Request Object??
Thanks!

Hi
User can only create custom Long text field (255 Charcter) . Currently system does not support custom note creation

Is it possible to send a 2D text array from a Labview progarm.......

I also posted this on the "Fieldpoint Family" board.
Is it possible to send a 2D text array from my LV program running on my PC to a LV program running in Realtime on my FP2010 Processor?
When I tried to build the RT program using the wizard, it didn't find the array and add it to the "Indicator List:". When I changed the array to a control, it didn't show up in the "Control List:" I tried it with TCP/IP, UDP, DataSocket, and Logos.
If it's possible, then how is it done?
Using LV7.0 Pro on Win2K
Thanks,
Mike

The Fieldpoint Family seems to be taking care of this one:
http://forums.ni.com/ni/board/message?board.id=110&message.id=3104
Andy F.
Applications Engineer
National Instruments
National Instruments

Is it possible to install Lightroom 4.1 on more than one computer using the same product code?

is it possible to install Lightroom 4.1 on more than one computer using the same product code?

Yes, your license key is cross platform PC & or Mac you are allowed to have two current installations with one in use at any point in time. You can uninstall / install as many times as is necessary so long as you adhere to the limits.

Re: Is it possible to change row colors on array fields ors

HI Martin!
Yes, it is possible to change row colors on array fields.
I have attached a PEX (tools.pex) which has an object which changes FillColor
and PenColor for Arrays. The PEX has it's own test window, so you can try
various combinations. (There are a few other Objects in the Project which are
not relevant
I'm not sure that you can change colors on individual choices in a scroll list.
I haven't tried playing around with it.
The test window actually changes the color of scroll lists as well.
The object keeps track of which rows have changed color, same with pen color, so
that when you scroll it keeps track of which rows are a different colors.
The pex is self-contained, just import the file and do a test run.
Please let me know if you have any problems.
-later
-labeaux
Is it possible to change row colors on array fields or scroll lists?
I need to create a list field that will allow me to dynamically change the
fillColor and/or penColor attributes of individual rows. (I just want to
highlight the rows, and those seem to be the obvious attributes...) It appears
you can't do that on scroll lists (the elements are list elements, and don't
have those attributes) and I can't figure out how to do it on an array field
either. Any ideas for how to accomplish this?
-Martin ([email protected])

FreshWebmuse,
Version 2 of iCal has the "Group Calendar" feature. It was released as part of Mac OS X v10.4, and if you really want/need that feature you will have to upgrade to Tiger.
;~)

Is it possible to create a 1 D array with the "build array VI"? when receiving random number

Hello all,
Is it possible to create a 1 D array with the "build array VI" when receiving random number?
I am receiving random data and the build array VI always create a 2D array which might cause some problem if you want to compute certain type of operation after.
Any example will be welcomed.
Thank you,
Israel

Hello Lynn and Yamaeda
First I want to Thank you Lynn for your linguistic contribution indeed "Build Array" is a primitive and not VI, thank you for the education. In reality what I am doing is simple.
I have two arrays of complex elements Array1 and Array2.
Array1 conains the complex elements ""(a0+ib0) ; (a1+ib1) ;...(an+ibn) ;
Array2 conains the complex elements ""(c0+id0) ; (c1+id1) ;...(cn+idn)
What I want to do is the multiplication of the first array by the conjugate of the second array element.
Array1*(Conjugate Array 2)" for the first element the results is "(a0.C0-b0.d0) + i(b0c0-a0d0)" and the etc...
and then taking the square root ([(a0.C0-b0.d0) power of 2]) + [(b0c0-a0d0) power of 2])
I was wondering if there were some dedicate primitive that could solve the computation above which is the cross correlation in Frequency domain.
Thank you very much.
Israel

Fail to index out images from an array of images!

Hi all,
I encountered this problem lately. I am indexing a number of images in an array using a for loop. Next the array of images (16 bit) is used somewhere else in the program; it is indexed and the images are to be processed and displayed. The problem is; when trying to index the images from the arrays using the index array the result is the same image regardless of the index!
Can anyone explain that for me?
Thanks in advance
Solved!
Go to Solution.

When you used the IMAQ create VI you specified each image to use the same name of "image". Each image has to have a unique name. I edited your VI to give a unique name for each image and I was able to view three different images in three different viewing panes.
Attachments:
Image Array Reworked.vi ‏19 KB

How to Return the Index of a Mouse-Selected Array Element in the View Interface of Diadem

Hello,
Does anybody have an idea of how to obtain the index of a mouse-selected array element in the View interface of Diadem??
Thanks!

Hi Ovidius,
Keep explaining. The only way I know of to trap a selected cell value in VIEW is to embed into the desired VIEW area a second non-modal SUDialog that has a Table control or an XTable control displaying the values of certain data channels. There are callbacks in both table controls for cell selection, and you can configure the table control to allow only single cell selection if that's what you want. The regular table control will be easier to program, but the XTable control will perform much better for larger channels.
But what happens with that value the user selected? Is it used for a calculation? Is it added to a report? Why would the user select that cell in a table rather than selecting the corresponding feature in a graph with the crosshair cursor?
Brad Turpin
DIAdem Product Support Engineer
National Instruments

Why is Array more efficient than flexible-size collection

it is a bit more tricky to understand the two advantges of Array as following:
1. access to items held in an array is often more efficient than access to the items in a comparable flexible-size collection,
2. arrays are able to store objects or primitive -type values, but flexible -size collection can store only object.
thanks in advance

it is a bit more tricky to understand the two
wo advantges of Array as following:
1. access to items held in an array is often more
e efficient than access to the items in a comparable
flexible-size collection,The standard dynamic data structure (with standard I mean member of the collections framework) comparable to the array is the ArrayList. In principle the access to an element is equally efficient in both cases. (There's some overhead because you have to do a method call in the ArrayList case). It's only in very low-level algoritms you need to use arrays. In most cases ArrayList is fine.
2. arrays are able to store objects or primitive
ve -type values, but flexible -size collection can
store only object.This is true with the standard collection, but there are alternative collections that can store primitives, for example,
http://pcj.sourceforge.net/
In the next version of Java there's a new concept call autoboxing. This means there's an implicit conversion taking place between primitive types and their corresponding wrapper class, say between int and Integer. This means you will be able to write your program AS IF you could store primitives in the standard collections.

ColdFusion 11: custom serialisers. More questions than answers

G'day:
I am reposting this from my blog ("ColdFusion 11: custom serialisers. More questions than answers") at the suggestion of Adobe support:
@dacCfml @ColdFusion Can you post your queries at http://t.co/8UF4uCajTC for all cfclient and mobile queries.— Anit Kumar Panda (@anitkumar85) April 29, 2014
This particular question is not regarding <cfclient>, hence posting it on the regular forum, not on the mobile-specific one as Anit suggested. I have edited this in places to remove language that will be deemed inappropriate by the censors here. Changes I have made are in [square brackets]. The forums software here has broken some of the styling, but so be it.
G'day:
I've been wanting to write an article about the new custom serialiser one can have in ColdFusion 11, but having looked at it I have more questions than I have answers, so I have put it off. But, equally, I have no place to ask the questions, so I'm stymied. So I figured I'd write an article covering my initial questions. Maybe someone can answer then.
ColdFusion 11 has added the notion of a custom serialiser a website can have (docs: "Support for pluggable serializer and deserializer"). The idea is that whilst Adobe can dictate the serialisation rules for its own data types, it cannot sensibly infer how a CFC instance might get serialised: as each CFC represents a different data "schema", there is no "one size fits all" approach to handling it. So this is where the custom serialiser comes in. Kind of. If it wasn't a bit rubbish. Here's my exploration thusfar.
One can specify a custom serialiser by adding a setting to Application.cfc:
component { this.name = "serialiser01"; this.customSerializer="Serialiser"; }
In this case the value - Serialiser - is the name of a CFC, eg:
// Serialiser.cfccomponent { public function canSerialize(){ logArgs(args=arguments, from=getFunctionCalledName()); return true; } public function canDeserialize(){ logArgs(args=arguments, from=getFunctionCalledName()); return true; } public function serialize(){ logArgs(args=arguments, from=getFunctionCalledName()); return "SERIALISED"; } public function deserialize(){ logArgs(args=arguments, from=getFunctionCalledName()); return "DESERIALISED"; } private function logArgs(required struct args, required string from){ var dumpFile = getDirectoryFromPath(getCurrentTemplatePath()) & "dump_#from#.html"; if (fileExists(dumpFile)){ fileDelete(dumpFile); } writeDump(var=args, label=from, output=dumpFile, format="html"); } }
This CFC needs to implement four methods:
canSerialize() - indicates whether something can be serialised by the serialiser;
canDeserialize() - indicates whether something can be deserialised by the serialiser;
serialize() - the function used to serialise something
deserialize() - the function used to deserialise something
I'm being purposely vague on those functions for a reason. I'll get to that.
The first [issue] in the implementation here is that for the custom serialisation to work, all four of those methods must be implemented in the serisalisation CFC. So common sense would dictate that a way to enforce that would be to require the CFC to implement an interface. That's what interfaces are for. Now I know people will argue the merit of having interfaces in CFML, but I don't really give a [monkey's] about that: CFML has interfaces, and this is what they're for. So when one specifies the serialiser in Application.cfc and it doesn't fulfil the interface requirement, it should error. Right then. When one specifies the inappropriate tool for the job. What instead happens is if the functions are omitted, one will get erratic behaviour in the application, through to outright errors when ColdFusion goes to call the functions and cannot find it. EG: if I have canSerialize() but no serialize() method, CF will error when it comes to serialise something:
JSON serialization failure: Unable to serialize to JSON.
Reason : The method serialize was not found in component C:/wwwroot/scribble/shared/git/blogExamples/coldfusion/CF11/customerserialiser/Serialiser .cfc.
The error occurred inC:/wwwroot/scribble/shared/git/blogExamples/coldfusion/CF11/customerserialiser/testBasic.c fm: line 4
2 : o = new Basic();
3 :
4 : serialised = serializeJson(o);5 : writeDump([serialised]);
6 :
Note that the error comes when I go to serialise something, not when ColdFusion is told about the serialiser in the first place. This is just lazy/thoughtless implementation on the part of Adobe. It invites bugs, and is just sloppy.
The second [issue] follows immediately on from this.
Given my sample serialiser above, I then run this test code to examine some stuff:
o = new Basic(); serialised = serializeJson(o); writeDump([serialised]); deserialised = deserializeJson(serialised); writeDump([deserialised]);
So all I'm doing is using (de)serializeJson() as a baseline to see how the functions work. here's Basic.cfc, btw:
component { }
And the test output:
array
1
SERIALISED
array
1
DESERIALISED
This is as one would expect. OK, so that "works". But now... you'll've noted I am logging the arguments each of the serialisation methods receives, as I got.
Here's the arguments passed to canSerialize():
canSerialize - struct
1
XML
My reaction to that is: "[WTH]?" Why is canSerialize() being passed the string "XML" when I'm trying to serialise an object of type Basic.cfc?
Here's the docs for canSerialize() (from the page I linked to earlier):
CanSerialize - Returns a boolean value and takes the "Accept Type" of the request as the argument. You can return true if you want the customserialzer to serialize the data to the passed argument type.
Again, back to "[WTH]?" What's the "Accept type" of the request? And what the hell has the request got to do with a call to serializeJson()? You might think that "Accept type" references some HTTP header or something, but there is no "Accept type" header in the HTTP spec (that I can find: "Hypertext Transfer Protocol -- HTTP/1.1: 14 Header Field Definitions"). There's an "Accept" header (in this case: "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8"), and other ones like "Accept-Encoding", "Accept-Language"... but none of which contain a value of "XML". Even if there was... how would it be relevant to the question as to whether a Basic.cfc instance can be serialised? Raised as bug: 3750730.
serialize() gets more sensible arguments:
serialize - struct
1
https://www.blogger.com/nullserialize - component scribble.shared.git.blogExamples.coldfusion.CF11.customerserialiser.Basic
2
JSON
So the first is the object to serialise (which surely should be part of the question canSerialize() is supposed to ask, and the format to serialise to. Cool.
canDeserialize() is passed this:
canDeserialize - struct
1
JSON
I guess it's because it's being called from deserializeJson(), so it's legit to expect the input value is indeed JSON. Fair enough. (Note: I'm not actually passing it JSON, but that's beside the point here).
And deserialize() is passed this:
deserialize - struct
1
SERIALISED
2
JSON
3
[empty string]
The first argument is the value to work on, and the second is the type of deserialisation to do. I have no idea what the third argument is for, and it's not mentioned directly or indirectly on that docs page. So dunno what the story is there.
The next issue isn't a code-oriented one, but an implementation one: how the hell are we expected to work with this?
The only way to work here is for each function to have a long array of IF/ELSEIF statements which somehow identify each object type that is serialisable, and then return true from canSerialise(), or in the case of serialize(), go ahead and do the serialisation. So this means this one CFC needs to know about everything which can be serialised in the entire application. Talk about a failure in "separation of concerns".
You know the best way of determining if an object can be seriaslised? Ask it! Don't rely on something else needing to know. This can be achieved very easily in one of two ways:
Check to see if the object implements a "Serializable" interface, which requires a serialize() method to exist.
Or simply take the duck-typing approach: if a CFC implements a serialize() method: it can be serialised. By calling that method. Job done.
Either approach would work fine, keeps things nicely encapsulated, and I see merits in both. And either make far more sense than Adobe's approach. Which is like something from the "OO Failures Special Needs" class.
Deserialisation is trickier. Because it relies on somehow working out how to deserialise() an object. I'm not sure of the best approach here, but - again - how to deserialise something should be as close to the thing needing deserialisation as possible. IE: something in the serialised data itself which can be used to bootstrap the process.
This could simply be a matter of specifying a CFC type at a known place in the serialised data. EG: Adobe stipulates that if the serialised data is JSON, and at the top level of the JSON is a key eg: type, and the value is an extant CFC... use that CFC's deserialize() method. Or it could look for an object which contains a type and a method, or whatever. But Adobe can specify a contract there.
The only place I see a centralised CFC being relevant here is for a mechanism for handling serialised data that is neither a ColdFusion internal type, nor identifiable as above. In this case, perhaps they could provide a mechanism for a serialisation router, which basically has a bunch of routes (if/elseifs if need be) which contains logic as to how to work out how to deserialise the data. But it should not be the actual deserialiser, it should simply have the mechanism to find out how to do it. This is actually pretty much the same in operation as the deserialize() approach in the current implementation, but it doesn't need the canDeserialize() method (it can return false at the end of the routing), and it doesn't need to know about serialising. And also it's not the main mechanism to do the deserialisation, it's just the fall back if the prescribed approach hasn't been used.
TBH, this still sounds a bit jerry-built, and I'm open for better suggestions. This is probably a well-trod subject in other languages, so it might be worth looking at how the likes of Groovy, Ruby or even PHP (eek!) achieve this.
There's still another issue with the current approach. And this demonstrates that the Adobe guys don't actually work with either CFML applications or even modern websites. This approach only works for a single, stand-alone website (like how we might have done in 2001). What if I'm not in the business of building websites, but I build applications such as FW/1 or ColdBox or the like? Or any sort of "helper" application. They cannot use the current Adobe implementation of the customserializer. Why? Because the serialisation code needs to be in a website-specific CFC. There's no way for Luis to implement a custom serialiser in ColdBox (for example), and then have it work for someone using ColdBox. Because it relies on either editing Application.cfc to specify a different CFC, or editing the existing customSerializer CFC. Neither of which are very good solutions. This should have been immediately apparent to the Adobe engineer(s) implementing this stuff had they actually had any experience with modern web applications (which generally aren't just a single monolithic site, but an aggregation of various other sub applications). Equally, I know it's not a case of having thought about this and [I'm just missing something], because when I asked them the other day, at first they didn't even get what I was asking, but when I clarified were just like "oh yeah... um... err... yeah, you can't do that. We'll... have to... ah yeah". This has been raised as bug 3750731.
So I declare the intent here valid, but the implementation to be more alpha- / pre-release- quality, not release-ready.
Still: it could be easily deprecated and rework fairly easily. I've raised this as bug 3750732.
Or am I missing something?
Adam

Yes, you can easily add additional questions to the Lookup.WebClient.Questions Lookup to allow some additional choices. We have added quite a few additional choices, we have noticed that removing them once people have selected them causes some errors.
You can also customize the required number of questions to select when each user sets them up as well as the number required to be correct to reset the password, these options are in the System Configuration settings.
If you need multi-language versions of the questions, you will also need to modify the appropriate language resource file in the xlWebApp.war file to provide the necessary translations for the values entered into the Lookup.

JAAS/Tomcat - providing more login information than just username/password

Sorry if this is a vague question or that I seem lazy, but I have been asked to say if an easy solution is available by the end of the day so I thought I would ask some of the experts!
I currently have a tomcat application which is protected by basic FORM protection with user name and password held within the database.
This application is to be rolled out and accessed by multiple clients, non of which should have access to each others data.
All of this is in place and a username is currently associated with a client. However we have been asked if the login can be changed so that the user logs in as
client-name/user-name/password for two reasons - firstly to avoid the possibility of the same username existing for more than one client and secondly as we now have a user who will be able to log in to more than one of the clients and creating two separate user names is not seen as the answer.
My guess is that this may be possible using JAAS though I have found no example showing this yet (and as always have not had much time to do so!)
Could anyone tell me if they think this is possible?
Many thanks in advance

ToddTobin wrote:
We are developing a custom SSPI module for our weblogic servers, and i have a concern
with remote logins for remote ejb calls.
The documentation statest that the UsernamePasswordLoginModule is a good way to
remotely log into a different BEA server so that ejb calls can be made from the
Security.runAs context. However, i need to have more information passed than
just the username password combination. e.g. applicationId that is making the
call, in addition to the userid.
The docs recommend creating your own login module, which is fine, but if i am
correct the UsernamePasswordLoginModule uses the environment object and Authenticate.athenticate,
to perform the login to my sspi. in that case the name is somehow translated
into a NameCallback and (credential) Password to a PasswordCallback. If i want
to add a different callback, "CallingAppCallback" where is that set in the environment
object? In the properties? and if so, how is that then accessed by my LoginModule
or AuthenticationProviderImpl?
I just dont see how to extend the functionality of UsernamePasswordLoginModule,
for remote-server logins?Yes, this is a major limitation. I had a similar limitation when I
implemented a kerberos client. If you can't fit what you want into two
string fields, you are stuffed. BEA really need to open up the API for
client-side login modules. To be fair to BEA, JAAS is useless so they
weren't working with something that was designed for distributed systems
in the first place.
Anyway I worked around it by base 64 encoding my data (which was binary
obviously). I suggest you come up with some way of encoding the
application id in the username, e.g user@id or something along those lines.
If you do come up with a better solution I'd be very interested to know!
Robert

Any suggestions of a more reliable program than Premiere CS6?

Any suggestions of a more reliable program than Premiere CS6? Too many issues that I spend more time trying to resolve than using the program creatively?

CS6 is completely solid and error free for me... what is your problem?
More information needed for someone to help... please click below and provide the requested information
-Premiere Pro Video Editing Information FAQ http://forums.adobe.com/message/4200840
•What is your exact brand/model graphics adapter (ATI or nVidia or ???)
•What is your exact graphics adapter driver version?
•Have you gone to the vendor web site to check for a newer driver?
•For Windows, do NOT rely on Windows Update to have current driver information
•-you need to go direct to the vendor web site and check updates for yourself
•ATI Driver Autodetect http://support.amd.com/en-us/download/auto-detect-tool
•nVidia Driver Downloads http://www.nvidia.com/Download/index.aspx?lang=en-us
Exactly what is INSIDE the video you are editing?
Codec & Format information, with 2 links inside for you to read http://forums.adobe.com/thread/1270588
Report back with the codec details of your file, use the programs below... A screen shot works well to SHOW people what you are doing
http://forums.adobe.com/thread/592070?tstart=30 for screen shot instructions
Free programs to get file information for PC/Mac http://mediaarea.net/en/MediaInfo/Download
Does your video use a VARIABLE Frame Rate or a Constant Frame Rate?

A Simpler, More Direct Question About Merge Joins

This thread is related to Merge Joins Should Be Faster and Merge Join but asks a simpler, more direct question:
Why does merge sort join choose to sort data that is already sorted? Here are some Explain query plans to illustrate my point.
SQL> EXPLAIN PLAN FOR
2 SELECT * FROM spoTriples ORDER BY s;
PLAN_TABLE_OUTPUT
|   0 | SELECT STATEMENT |              |   998K|    35M| 5311   (1)| 00:01:04|
|   1 | INDEX FULL SCAN | PKSPOTRIPLES |   998K|    35M| 5311   (1)| 00:01:04|
---------------------------------------------------------------------------------Notice that the plan does not involve a SORT operation. This is because spoTriples is an Index-Organized Table on the primary key index of (s,p,o), which contains all of the columns in the table. This means the table is already sorted on s, which is the column in the ORDER BY clause. The optimizer is taking advantage of the fact that the table is already sorted, which it should.
Now look at this plan:
SQL> EXPLAIN PLAN FOR
2 SELECT /*+ USE_MERGE(t1 t2) */ t1.s, t2.s
3 FROM spoTriples t1, spoTriples t2
4 WHERE t1.s = t2.s;
Explained.
PLAN_TABLE_OUTPUT
|   0 | SELECT STATEMENT       |              |    11M|   297M|       | 13019 (6)| 00:02:37 |
|   1 | MERGE JOIN            |              |    11M|   297M|       | 13019 (6)| 00:02:37 |
|   2 |   SORT JOIN            |              |   998K|    12M|    38M| 6389 (4)| 00:01:17 |
|   3 |    INDEX FAST FULL SCAN| PKSPOTRIPLES |   998K|    12M|       | 1460 (3)| 00:00:18 |
|* 4 |   SORT JOIN            |              |   998K|    12M|    38M| 6389 (4)| 00:01:17 |
|   5 |    INDEX FAST FULL SCAN| PKSPOTRIPLES |   998K|    12M|       | 1460 (3)| 00:00:18 |
Predicate Information (identified by operation id):
   4 - access("T1"."S"="T2"."S")
       filter("T1"."S"="T2"."S")I'm doing a self join on the column by which the table is sorted. I'm using a hint to force a merge join, but despite the data already being sorted, the optimizer insists on sorting each instance of spoTriples before doing the merge join. The sort should be unnecessary for the same reason that it is unnecessary in the case with the ORDER BY above.
Is there anyway to make Oracle be aware of and take advantage of the fact that it doesn't have to sort this data before merge joining it?

Licensing questions are best addressed by visiting the Oracle store, or contacting a salesrep in your area
But I doubt you can redistribute the product if you aren't licensed yourself.
Question 3 and 4 have obvious answers
3: Even if you could this is illegal
4: if tnsping is not included in the client, tnsping is not included in the client, and there will be no replacement.
Tnsping only establishes whether a listener is running and shouldn't be called from an application
Sybrand Bakker
Senior Oracle DBA

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