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  • Can anyone explain this pience of snippet?

    - by karthick6891
    Can anyone explain the following code,forget the sin and cosine parts..Is it trying to build a space for the object objectsInScene = new Array(); for (var i=space; i<180; i+=space) { for (var angle=0; angle<360; angle+=space) { var object = {}; var x = Math.sin(radian*i)*radius; object.x = Math.cos(angle*radian)*x; object.y = Math.cos(radian*i)*radius; object.z = Math.sin(angle*radian)*x; objectsInScene.push(object); } }

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  • Explain DLL Dependencies to a lay person

    - by wheaties
    This follows from a previous posting I made about lack of a clean test machine for software installations. I'm doing a bad job of explaining how DLL dependencies work and how some machines might not have the right libraries at the time of installation. The problem is that it's being viewed as a defect with the build process. I'm trying to educate the higher ups that it's not the build process per se but rather the installation process which is to blame. Here's a quote from my boss relating subcontractor work to our work to put it into perspective: I'm not a software person. All I see is that when they hand something to us it just works but when we hand something to the client there's all sorts of problems. There must be something wrong with how you're building the code. It's very easy to see how someone who is smart (scarily smart) could come to the wrong conclusion. So how would you explain the whole DLL dependency issue?

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  • Explain this O(n log n) algorithm for the Cat/Egg Throwing Problem

    - by ripper234
    This problem (How many cats you need to throw out of a building in order to determine the maximal floor where such a cat will survive. Quite cruel, actually), has an accepted answer with O(n^3) complexity. The problem is equivalent to this Google Code Jam, which should be solvable for N=2000000000. It seems that the O(n^3) solution is not good enough to solve it. From looking in the solutions page, jdmetz's solution (#2) seems to be O(n log n). I don't quite understand the algorithm. Can someone explain it? Edit

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  • can anyone explain the why the the 1st example gets different results than the following 2

    - by klumsy
    $b = (2,3) $myarray1 = @(,$b,$b) $myarray1[0].length #this will be 1 $myarray1[1].length $myarray2 = @( ,$b ,$b ) $myarray2[0].length #this will be 2 $myarray[1].length $myarray3 = @(,$b ,$b ) $myarray3[0].length #this will be 2 $myarray3[1].length UPDATE I think on #powershell IRC we have worked it out, Here is another example that demonstrates the danger of breaking with the comma on the following line rather than the top line when listing multiple items in an array over multiple lines. $b = (1..20) $a = @( $b, $b ,$b, $b, $b ,$b) for($i=0;$i -lt $a.length;$i++) { $a[$i].length } "--------" $a = @( $b, $b ,$b ,$b, $b ,$b) for($i=0;$i -lt $a.length;$i++) { $a[$i].length } produces 20 20 20 20 20 20 -------- 20 20 20 1 20 20 I'm curious how people will explain this. I think i understand it now, but would have trouble explaining it in a concise understandable fashion, though the above example goes somewhat towards that goal.

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  • please explain the dataflow in MVC specially in codeigniter

    - by pokhara
    Dear friends, Can anyone please explain me the object flow in codeigniter MVC ? I can see for example when I put the followong code in controller it works, but i am not being able to figure out which part of this goes in model in vews. I tried several ways but coudn't. When i use the example codes from other it works but myself i am getting confused. Please help $query = $this->db->query("YOUR QUERY"); foreach ($query->result() as $row) { echo $row->title; echo $row->name; echo $row->body; }

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  • Can someone explain Kohana 3's routing system?

    - by alex
    In bootstrap.php, where you set routes, I'm having a hard time getting them to work. I read some documentation a while ago that I can't seem to find again that explains them. Here is one of my examples Route::set('products', 'products/(type)', array('type' => '.+')) ->defaults(array( 'controller' => 'articles', 'action' => 'view_product', 'page' => 'shock-absorbers', )); I thought that would mean a request like products/something would load up the articles controller, and the action_view_product method. But I can't get it to work. Can someone please explain to me exactly how they work, and what all the method parameters are?

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  • Help me to explain the F# Matrix transpose function

    - by Kev
    There is a Matrix transpose function: let rec transpose = function | (_::_)::_ as M -> List.map List.head M :: transpose (List.map List.tail M) | _ -> [] [[1; 2; 3]; [4; 5; 6]; [7; 8; 9]] |> transpose |> printfn "%A" It works fine. What does ( _ :: _ ) :: _ mean? I don't understand the whole code! Who can explain it? Thank You!

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  • Can anybody explain the working of following code...?

    - by Siddhi
    Can anybody explain the working of following code...? interface myInterface{} public class Main { public static void main(String[] args) { System.out.println(new myInterface(){public String toString(){return "myInterfacetoString";}}); System.out.println(new myInterface(){public String myFunction(){return "myInterfacemyFunction";}}); } } Output is... myInterfacetoString primitivedemo.Main$2@9304b1 All answers saying that myInterface in println() statement is anonymous class. But as I already declared it as an interface, why does it allow me to create anonymous class of same name....? again...if these are anonymous classes then class main should allow me to give any name to these anonymous classes..But if try to do so..I'm getting compilation error

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  • MySQL query optimization - distinct, order by and limit

    - by Manuel Darveau
    I am trying to optimize the following query: select distinct this_.id as y0_ from Rental this_ left outer join RentalRequest rentalrequ1_ on this_.id=rentalrequ1_.rental_id left outer join RentalSegment rentalsegm2_ on rentalrequ1_.id=rentalsegm2_.rentalRequest_id where this_.DTYPE='B' and this_.id<=1848978 and this_.billingStatus=1 and rentalsegm2_.endDate between 1273631699529 and 1274927699529 order by rentalsegm2_.id asc limit 0, 100; This query is done multiple time in a row for paginated processing of records (with a different limit each time). It returns the ids I need in the processing. My problem is that this query take more than 3 seconds. I have about 2 million rows in each of the three tables. Explain gives: +----+-------------+--------------+--------+-----------------------------------------------------+---------------+---------+--------------------------------------------+--------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------------+--------+-----------------------------------------------------+---------------+---------+--------------------------------------------+--------+----------------------------------------------+ | 1 | SIMPLE | rentalsegm2_ | range | index_endDate,fk_rentalRequest_id_BikeRentalSegment | index_endDate | 9 | NULL | 449904 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | rentalrequ1_ | eq_ref | PRIMARY,fk_rental_id_BikeRentalRequest | PRIMARY | 8 | solscsm_main.rentalsegm2_.rentalRequest_id | 1 | Using where | | 1 | SIMPLE | this_ | eq_ref | PRIMARY,index_billingStatus | PRIMARY | 8 | solscsm_main.rentalrequ1_.rental_id | 1 | Using where | +----+-------------+--------------+--------+-----------------------------------------------------+---------------+---------+--------------------------------------------+--------+----------------------------------------------+ I tried to remove the distinct and the query ran three times faster. explain without the query gives: +----+-------------+--------------+--------+-----------------------------------------------------+---------------+---------+--------------------------------------------+--------+-----------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+--------------+--------+-----------------------------------------------------+---------------+---------+--------------------------------------------+--------+-----------------------------+ | 1 | SIMPLE | rentalsegm2_ | range | index_endDate,fk_rentalRequest_id_BikeRentalSegment | index_endDate | 9 | NULL | 451972 | Using where; Using filesort | | 1 | SIMPLE | rentalrequ1_ | eq_ref | PRIMARY,fk_rental_id_BikeRentalRequest | PRIMARY | 8 | solscsm_main.rentalsegm2_.rentalRequest_id | 1 | Using where | | 1 | SIMPLE | this_ | eq_ref | PRIMARY,index_billingStatus | PRIMARY | 8 | solscsm_main.rentalrequ1_.rental_id | 1 | Using where | +----+-------------+--------------+--------+-----------------------------------------------------+---------------+---------+--------------------------------------------+--------+-----------------------------+ As you can see, the Using temporary is added when using distinct. I already have an index on all fields used in the where clause. Is there anything I can do to optimize this query? Thank you very much!

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  • Can someone please explain this lazy evaluation code?

    - by Tejs
    So, this question was just asked on SO: http://stackoverflow.com/questions/2740001/how-to-handle-an-infinite-ienumerable My sample code: public static void Main(string[] args) { foreach (var item in Numbers().Take(10)) Console.WriteLine(item); Console.ReadKey(); } public static IEnumerable<int> Numbers() { int x = 0; while (true) yield return x++; } Can someone please explain why this is lazy evaluated? I've looked up this code in Reflector, and I'm more confused than when I began. Reflector outputs: public static IEnumerable<int> Numbers() { return new <Numbers>d__0(-2); } For the numbers method, and looks to have generated a new type for that expression: [DebuggerHidden] public <Numbers>d__0(int <>1__state) { this.<>1__state = <>1__state; this.<>l__initialThreadId = Thread.CurrentThread.ManagedThreadId; } This makes no sense to me. I would have assumed it was an infinite loop until I put that code together and executed it myself.

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  • Image Line Trace Math Help Hard To Explain

    - by Ozzy
    Hi all, sorry for the confusing title, its really hard for me to explain what i want. So i created this image :) Ok so the two RED dots are points on an image. The distance between them isnt important. What I want to do is, Using the coordinates for the two dots, work out the angle of the space between them (as shown by the black line between the red dots) Then once the angle is found, on the last red dot, create two points which cross the angle of the first line. Then from that, scan a Half semicircle and get the coordinates of every pixel of the image that the orange line passes. I dnot know if this makes any sense to you lot so i drew another picture: As you can see in the second picture, my idea is applied to a line drawn on a black canavs. The two red dots are the starting coordinates then at the end of the two dots, a less then half semicircle is created. The part that is orange shows the pixels of the image that should be recorded. I have no clue how to start this, so if anyone has any ideas on how i can or on what i need to do, any help is much appreciated :)

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  • Can someone explain me this code ?

    - by VaioIsBorn
    #include <stdio.h> #include <unistd.h> #include <string.h> int good(int addr) { printf("Address of hmm: %p\n", addr); } int hmm() { printf("Win.\n"); execl("/bin/sh", "sh", NULL); } extern char **environ; int main(int argc, char **argv) { int i, limit; for(i = 0; environ[i] != NULL; i++) memset(environ[i], 0x00, strlen(environ[i])); int (*fptr)(int) = good; char buf[32]; if(strlen(argv[1]) <= 40) limit = strlen(argv[1]); for(i = 0; i <= limit; i++) { buf[i] = argv[1][i]; if(i < 36) buf[i] = 0x41; } int (*hmmptr)(int) = hmm; (*fptr)((int)hmmptr); return 0; } I don't really understand the code above, i have it from an online game - i should supply something in the arguments so it would give me shell, but i don't get it how it works so i don't know what to do. So i need someone that would explain it what it does, how it's working and the stuff. Thanks.

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  • Can someone please explain Cursor in android ?

    - by Prabhat
    Can some one explain how the cursor exactly works ? Or the flow of the following part of the code ? I know that this is sub activity and all but I did not understand how Cursor works exactly. final Uri data = Uri.parse("content://contacts/people/"); final Cursor c = managedQuery(data, null, null, null, null); String[] from = new String[] { People.NAME }; int[] to = new int[] { R.id.itemTextView }; SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,R.layout.listitemlayout, c, from, to); ListView lv = (ListView) findViewById(R.id.contactListView); lv.setAdapter(adapter); lv.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView<?> parent, View view, int pos, long id) { c.moveToPosition(pos); int rowId = c.getInt(c.getColumnIndexOrThrow("_id")); Uri outURI = Uri.parse(data.toString() + rowId); Intent outData = new Intent(); outData.setData(outURI); setResult(Activity.RESULT_OK, outData); finish(); } }); Thanks.

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  • How to explain to client that you can't give them some of the source

    - by Bo
    We have a number of AS/Flex components that we've built over time and improved upon. They've been turned into components so they can be reused in different projects and save us time. So you can think of them as part of an in-house framework of sorts. We're now realizing that it doesn't make sense to release the source code for these components to the various clients as part of the project, because technically this code isn't really owned by the clients. So my question When a client comes to you, how do you explain to them that you can't give them the full source code for those components. The client doesn't understand the difference, he just expects you to give them all the code for the site that he paid you to do. He doesn't understand that this code has taken you a lot longer to write than what he's paying for his site. But since he doesn't understand, he would get turned off and thinks you're ripping him off or something. How do you handle this situation? What do you tell clients upfront? Do you advertise it on your site from the very beginning? How do you handle their objections so they still hire you? As a side question, how often do you give AS and Flex source code to your clients? In the case when the code doesn't have any in-house components that you reuse in several projects, and in the case when it does have in-house components.

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  • explain notifier.c from the Linux kernel

    - by apollon
    I'm seeking to fully understand the following code snippet from kernel/notifier.c. I have read and built simple link lists and think I get the construct from K&R's C programming. The second line below which begins with the 'int' appears to be two items together which is unclear. The first is the (*notifier_call) which I believe has independent but related significance with the second containing a 'notifier block' term. Can you explain how it works in detail? I understand that there is a function pointer and multiple subscribers possible. But I lack the way to tie these facts together, and could use a primer or key so I exactly understand how the code works. The third line looks to contain the linking structure, or recursive nature. Forgive my terms, and correct them as fit as I am a new student of computer science terminology. struct notifier_block { int (*notifier_call)(struct notifier_block *, unsigned long, void *); struct notifier_block *next; int priority; };

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  • Please explain this delete top 100 SQL syntax

    - by Patrick
    Basically I want to do this: delete top( 100 ) from table order by id asc but MS SQL doesn't allow order in this position The common solution seems to be this: DELETE table WHERE id IN(SELECT TOP (100) id FROM table ORDER BY id asc) But I also found this method here: delete table from (select top (100) * from table order by id asc) table which has a much better estimated execution plan (74:26). Unfortunately I don't really understand the syntax, please can some one explain it to me? Always interested in any other methods to achieve the same result as well. EDIT: I'm still not getting it I'm afraid, I want to be able to read the query as I read the first two which are practically English. The above queries to me are: delete the top 100 records from table, with the records ordered by id ascending delete the top 100 records from table where id is anyone of (this lot of ids) delete table from (this lot of records) table I can't change the third one into a logical English sentence... I guess what I'm trying to get at is how does this turn into "delete from table (this lot of records)". The 'from' seems to be in an illogical position and the second mention of 'table' is logically superfluous (to me).

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  • oracle using index even though there is no filter criteeria specified

    - by Kaushik
    In this query: SELECT WTTEMPLATE.TEMPLATEuID, MAX (WTTRX.VALUEDATE) AS template_last_use_date FROM wttemplate, wttrx WHERE WTTEMPLATE.TEMPLATEID = WTTRX.TEMPLATEID(+) AND WTTEMPLATE.CUSTID = WTTRX.CUSTID GROUP BY WTTEMPLATE.TEMPLATEuID The explain plan shows:index fast full scan using indexes on WTTEMPLATE.TEMPLATEID and (WTTRX.TEMPLATEID,WTTRX.CUSTID). My question is this: I have not specified any filter criteria , so how can it use indexes? It should do full scan...right?

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  • MySQL Query performance - huge difference in time

    - by Damo
    I have a query that is returning in vastly different amounts of time between 2 datasets. For one set (database A) it returns in a few seconds, for the other (database B)....well I haven't waited long enough yet, but over 10 minutes. I have dumped both of these databases to my local machine where I can reproduce the issue running MySQL 5.1.37. Curiously, database B is smaller than database A. A stripped down version of the query that reproduces the problem is: SELECT * FROM po_shipment ps JOIN po_shipment_item psi USING (ship_id) JOIN po_alloc pa ON ps.ship_id = pa.ship_id AND pa.UID_items = psi.UID_items JOIN po_header ph ON pa.hdr_id = ph.hdr_id LEFT JOIN EVENT_TABLE ev0 ON ev0.TABLE_ID1 = ps.ship_id AND ev0.EVENT_TYPE = 'MAS0' LEFT JOIN EVENT_TABLE ev1 ON ev1.TABLE_ID1 = ps.ship_id AND ev1.EVENT_TYPE = 'MAS1' LEFT JOIN EVENT_TABLE ev2 ON ev2.TABLE_ID1 = ps.ship_id AND ev2.EVENT_TYPE = 'MAS2' LEFT JOIN EVENT_TABLE ev3 ON ev3.TABLE_ID1 = ps.ship_id AND ev3.EVENT_TYPE = 'MAS3' LEFT JOIN EVENT_TABLE ev4 ON ev4.TABLE_ID1 = ps.ship_id AND ev4.EVENT_TYPE = 'MAS4' LEFT JOIN EVENT_TABLE ev5 ON ev5.TABLE_ID1 = ps.ship_id AND ev5.EVENT_TYPE = 'MAS5' WHERE ps.eta >= '2010-03-22' GROUP BY ps.ship_id LIMIT 100; The EXPLAIN query plan for the first database (A) that returns in ~2 seconds is: +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+------------------------------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+------------------------------+------+----------------------------------------------+ | 1 | SIMPLE | ps | range | PRIMARY,IX_ETA_DATE | IX_ETA_DATE | 4 | NULL | 174 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | ev0 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_PROD.ps.ship_id,const | 1 | | | 1 | SIMPLE | ev1 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_PROD.ps.ship_id,const | 1 | | | 1 | SIMPLE | ev2 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_PROD.ps.ship_id,const | 1 | | | 1 | SIMPLE | ev3 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_PROD.ps.ship_id,const | 1 | | | 1 | SIMPLE | ev4 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_PROD.ps.ship_id,const | 1 | | | 1 | SIMPLE | ev5 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_PROD.ps.ship_id,const | 1 | | | 1 | SIMPLE | psi | ref | PRIMARY,IX_po_shipment_item_po_shipment1,FK_po_shipment_item_po_shipment1 | IX_po_shipment_item_po_shipment1 | 4 | UNIVIS_PROD.ps.ship_id | 1 | | | 1 | SIMPLE | pa | ref | IX_po_alloc_po_shipment_item2,IX_po_alloc_po_details_old,FK_po_alloc_po_shipment1,FK_po_alloc_po_shipment_item1,FK_po_alloc_po_header1 | FK_po_alloc_po_shipment1 | 4 | UNIVIS_PROD.psi.ship_id | 5 | Using where | | 1 | SIMPLE | ph | eq_ref | PRIMARY,IX_HDR_ID | PRIMARY | 4 | UNIVIS_PROD.pa.hdr_id | 1 | | +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+------------------------------+------+----------------------------------------------+ The EXPLAIN query plan for the second database (B) that returns in 600 seconds is: +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+--------------------------------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+--------------------------------+------+----------------------------------------------+ | 1 | SIMPLE | ps | range | PRIMARY,IX_ETA_DATE | IX_ETA_DATE | 4 | NULL | 38 | Using where; Using temporary; Using filesort | | 1 | SIMPLE | psi | ref | PRIMARY,IX_po_shipment_item_po_shipment1,FK_po_shipment_item_po_shipment1 | IX_po_shipment_item_po_shipment1 | 4 | UNIVIS_DEV01.ps.ship_id | 1 | | | 1 | SIMPLE | ev0 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_DEV01.psi.ship_id,const | 1 | | | 1 | SIMPLE | ev1 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_DEV01.psi.ship_id,const | 1 | | | 1 | SIMPLE | ev2 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_DEV01.ps.ship_id,const | 1 | | | 1 | SIMPLE | ev3 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_DEV01.psi.ship_id,const | 1 | | | 1 | SIMPLE | ev4 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_DEV01.psi.ship_id,const | 1 | | | 1 | SIMPLE | ev5 | ref | IX_EVENT_ID_EVENT_TYPE | IX_EVENT_ID_EVENT_TYPE | 36 | UNIVIS_DEV01.ps.ship_id,const | 1 | | | 1 | SIMPLE | pa | ref | IX_po_alloc_po_shipment_item2,IX_po_alloc_po_details_old,FK_po_alloc_po_shipment1,FK_po_alloc_po_shipment_item1,FK_po_alloc_po_header1 | IX_po_alloc_po_shipment_item2 | 4 | UNIVIS_DEV01.ps.ship_id | 4 | Using where | | 1 | SIMPLE | ph | eq_ref | PRIMARY,IX_HDR_ID | PRIMARY | 4 | UNIVIS_DEV01.pa.hdr_id | 1 | | +----+-------------+-------+--------+----------------------------------------------------------------------------------------------------------------------------------------+----------------------------------+---------+--------------------------------+------+----------------------------------------------+ When database B is running I can look at the MySQL Administrator and the state remains at "Copying to tmp table" indefinitely. Database A also has this state but for only a second or so. There are no differences in the table structure, indexes, keys etc between these databases (I have done show create tables and diff'd them). The sizes of the tables are: database A: po_shipment 1776 po_shipment_item 1945 po_alloc 36298 po_header 71642 EVENT_TABLE 1608 database B: po_shipment 463 po_shipment_item 470 po_alloc 3291 po_header 56149 EVENT_TABLE 1089 Some points to note: Removing the WHERE clause makes the query return < 1 sec. Removing the GROUP BY makes the query return < 1 sec. Removing ev5, ev4, ev3 etc makes the query get faster for each one removed. Can anyone suggest how to resolve this issue? What have I missed? Many Thanks.

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  • How can I explain object-oriented programming to someone who's only coded in Fortran 77? [closed]

    - by Zonedabone
    Possible Duplicate: How can I explain object-oriented programming to someone who’s only coded in Fortran 77? My mother did her college thesis in Fortran, and now (over a decade later) needs to learn c++ for fluids simulations. She is able to understand all of the procedural programming, but no matter how hard I try to explain objects to her, it doesn't stick. (I do a lot of work with Java, so I know how objects work) I think I might be explaining it in too high-level ways, so it isn't really making sense to someone who's never worked with them at all and grew up in the age of purely functional programming. Is there any simple way I can explain them to her that will help her understand? Thanks for the help in advance.

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  • Explain difference in SQLIO numbers for RAID 0 versus RAID 5 over 6 disks

    - by markn
    When using the SQLIO benchmark tool on a 4-core Dell server with 6 15k 450GB (fast) drives, RAID 0, we found the max throughput was 2MB per second. But when configured as RAID 5, we get 30 MB per second. It seems that the RAID controller, Dell Perc 5i integrated controller, is maxing out the throughput per disk. With RAID 5, I expect to get a bump due to stripping, but not a 15x difference. Like good programmers, we suspect the hardware , but we could be missing something. This is predominately write traffic.

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  • Please explain some of Paul Graham's points on LISP

    - by kunjaan
    I need some help understanding some of the points from Paul Graham's article http://www.paulgraham.com/diff.html A new concept of variables. In Lisp, all variables are effectively pointers. Values are what have types, not variables, and assigning or binding variables means copying pointers, not what they point to. A symbol type. Symbols differ from strings in that you can test equality by comparing a pointer. A notation for code using trees of symbols. The whole language always available. There is no real distinction between read-time, compile-time, and runtime. You can compile or run code while reading, read or run code while compiling, and read or compile code at runtime. What do these points mean How are they different in languages like C or Java? Do any other languages other than LISP family languages have any of these constructs now?

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  • Please Explain Drupal schema and drupal_write_record

    - by Aaron
    Hi. A few questions. 1) Where is the best place to populate a new database table when a module is first installed, enabled? I need to go and get some data from an external source and want to do it transparently when the user installs/enables my custom module. I create the schema in {mymodule}_schema(), do drupal_install_schema({tablename}); in hook_install. Then I try to populate the table in hook_enable using drupal_write_record. I confirmed the table was created, I get no errors when hook_enable executes, but when I query the new table, I get no rows back--it's empty. Here's one variation of the code I've tried: /** * Implementation of hook_schema() */ function ncbi_subsites_schema() { // we know it's MYSQL, so no need to check $schema['ncbi_subsites_sites'] = array( 'description' => 'The base table for subsites', 'fields' => array( 'site_id' => array( 'description' => 'Primary id for site', 'type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE, ), // end site_id 'title' => array( 'description' => 'The title of the subsite', 'type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => '', ), //end title field 'url' => array( 'description' => 'The URL of the subsite in Production', 'type' => 'varchar', 'length' => 255, 'default' => '', ), //end url field ), //end fields 'unique keys' => array( 'site_id'=> array('site_id'), 'title' => array('title'), ), //end unique keys 'primary_key' => array('site_id'), ); // end schema return $schema; } Here's hook_install: function ncbi_subsites_install() { drupal_install_schema('ncbi_subsites'); } Here's hook_enable: function ncbi_subsites_enable() { drupal_get_schema('ncbi_subsites_site'); // my helper function to get data for table (not shown) $subsites = ncbi_subsites_get_subsites(); foreach( $subsites as $name=>$attrs ) { $record = new stdClass(); $record->title = $name; $record->url = $attrs['homepage']; drupal_write_record( 'ncbi_subsites_sites', $record ); } } Can someone tell me what I'm missing?

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  • Explain BFS and DFS in terms of backtracking

    - by HH
    Wikipedia about DFS Depth-first search (DFS) is an algorithm for traversing or searching a tree, tree structure, or graph. One starts at the root (selecting some node as the root in the graph case) and explores as far as possible along each branch before backtracking. So is BFS? "an algorithm that choose a starting node, checks all nodes -- backtracks --, chooses the shortest path, chose neighbour nodes -- backtracks --, chose the shortest path -- finally finds the optimal path because of traversing each path due to continuos backtracking. Regex, find's pruning -- backtracking? The term backtracking confuseses due to its variety of use. UNIX find's pruning an SO-user explained with backtracking. Regex Buddy uses the term "catastrophic backtracking" if you do not limit the scope of your Regexes. It seems to be too wide umbrella-term. So: how do you define "Backtracking" GRAPH-theoretically? what is "backtracking" in BFS and DFS?

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