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  • Optimize slow ranking query

    - by Juan Pablo Califano
    I need to optimize a query for a ranking that is taking forever (the query itself works, but I know it's awful and I've just tried it with a good number of records and it gives a timeout). I'll briefly explain the model. I have 3 tables: player, team and player_team. I have players, that can belong to a team. Obvious as it sounds, players are stored in the player table and teams in team. In my app, each player can switch teams at any time, and a log has to be mantained. However, a player is considered to belong to only one team at a given time. The current team of a player is the last one he's joined. The structure of player and team is not relevant, I think. I have an id column PK in each. In player_team I have: id (PK) player_id (FK -> player.id) team_id (FK -> team.id) Now, each team is assigned a point for each player that has joined. So, now, I want to get a ranking of the first N teams with the biggest number of players. My first idea was to get first the current players from player_team (that is one record top for each player; this record must be the player's current team). I failed to find a simple way to do it (tried GROUP BY player_team.player_id HAVING player_team.id = MAX(player_team.id), but that didn't cut it. I tried a number of querys that didn't work, but managed to get this working. SELECT COUNT(*) AS total, pt.team_id, p.facebook_uid AS owner_uid, t.color FROM player_team pt JOIN player p ON (p.id = pt.player_id) JOIN team t ON (t.id = pt.team_id) WHERE pt.id IN ( SELECT max(J.id) FROM player_team J GROUP BY J.player_id ) GROUP BY pt.team_id ORDER BY total DESC LIMIT 50 As I said, it works but looks very bad and performs worse, so I'm sure there must be a better way to go. Anyone has any ideas for optimizing this? I'm using mysql, by the way. Thanks in advance Adding the explain. (Sorry, not sure how to format it properly) id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t ALL PRIMARY NULL NULL NULL 5000 Using temporary; Using filesort 1 PRIMARY pt ref FKplayer_pt77082,FKplayer_pt265938,new_index FKplayer_pt77082 4 t.id 30 Using where 1 PRIMARY p eq_ref PRIMARY PRIMARY 4 pt.player_id 1 2 DEPENDENT SUBQUERY J index NULL new_index 8 NULL 150000 Using index

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  • Finding an available network port on the machine

    - by Tomer Vromen
    I'm trying to implement a simple FTP server (a variation of the EFTP protocol) in linux. When a client connects and sends the PASV command, the server should respond with a port number, so the client can connect to that port to transmit the file. How can the server choose a port number? Do I need to iterate through all the ports from 1024 to 65535 until I find a port that the process can bind to? I know that calling bind() with 0 as the port automatically chooses the port to bind to, but then how can I know which port was chosen? Many thanks.

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  • In Python, how to use a C++ function which returns an allocated array of structs via a ** parameter?

    - by Jon-Eric
    I'd like to use some existing C++ code, NvTriStrip, in a Python tool. SWIG easily handles the functions with simple parameters, but the main function, GenerateStrips, is much more complicated. What do I need to put in the SWIG interface file to indicate that primGroups is really an output parameter and that it must be cleaned up with delete[]? /////////////////////////////////////////////////////////////////////////// // GenerateStrips() // // in_indices: input index list, the indices you would use to render // in_numIndices: number of entries in in_indices // primGroups: array of optimized/stripified PrimitiveGroups // numGroups: number of groups returned // // Be sure to call delete[] on the returned primGroups to avoid leaking mem // bool GenerateStrips( const unsigned short* in_indices, const unsigned int in_numIndices, PrimitiveGroup** primGroups, unsigned short* numGroups, bool validateEnabled = false ); FYI, here is the PrimitiveGroup declaration: enum PrimType { PT_LIST, PT_STRIP, PT_FAN }; struct PrimitiveGroup { PrimType type; unsigned int numIndices; unsigned short* indices; PrimitiveGroup() : type(PT_STRIP), numIndices(0), indices(NULL) {} ~PrimitiveGroup() { if(indices) delete[] indices; indices = NULL; } };

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  • Parsing string logic issue c#

    - by N0xus
    This is a follow on from this question My program is taking in a string that is comprised of two parts: a distance value and an id number respectively. I've split these up and stored them in local variables inside my program. All of the id numbers are stored in a dictionary and are used check the incoming distance value. Though I should note that each string that gets sent into my program from the device is passed along on a single string. The next time my program receives that a signal from a device, it overrides the previous data that was there before. Should the id key coming into my program match one inside my dictionary, then a variable held next to my dictionaries key, should be updated. However, when I run my program, I don't get 6 different values, I only get the same value and they all update at the same time. This is all the code I have written trying to do this: Dictionary<string, string> myDictonary = new Dictionary<string, string>(); string Value1 = ""; string Value2 = ""; string Value3 = ""; string Value4 = ""; string Value5 = ""; string Value6 = ""; void Start() { myDictonary.Add("11111111", Value1); myDictonary.Add("22222222", Value2); myDictonary.Add("33333333", Value3); myDictonary.Add("44444444", Value4); myDictonary.Add("55555555", Value5); myDictonary.Add("66666666", Value6); } private void AppendString(string message) { testMessage = message; string[] messages = message.Split(','); foreach(string w in messages) { if(!message.StartsWith(" ")) outputContent.text += w + "\n"; } messageCount = "RSSI number " + messages[0]; uuidString = "UUID number " + messages[1]; if(myDictonary.ContainsKey(messages[1])) { Value1 = messageCount; Value2 = messageCount; Value3 = messageCount; Value4 = messageCount; Value5 = messageCount; Value6 = messageCount; } } How can I get it so that when programs recives the first key, for example 1111111, it only updates Value1? The information that comes through can be dynamic, so I'd like to avoid harding as much information as I possibly can.

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  • What did I do wrong with this function?

    - by Felipe Galdino Campos
    I don't know what I did - it's wrong . Can someone help me? def insert_sequence(dna1, dna2, number): '''(str, str, int) -> str Return the DNA sequence obtained by inserting the second DNA sequence at the given index. (You can assume that the index is valid.) >>> insert_sequence('CCGG', 'AT', 2) 'CCATGG' >>> insert_sequence('TTGC', 'GG', 2) 'TTGGGC' ''' index = 0 result = ''; for string in dna1: if index == number: result = result + dna2 result = result + string index += 1 print(result)

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  • Getting key/value pairs from plist-style xml using simplexml in php

    - by Anthony
    Here is an example bit from the xml file: <array> <dict> <key>Name</key> <string>Joe Smith</string> <key>Type</key> <string>Profile</string> <key>Role</key> <string>User</string> <key>Some Number</key> <integer>1</integer> <key>Some Boolean</key> <true/> </dict> </array> I have two separate goals. The first is to extract an array from the dictnode that would look like: [Name] => Joe Smith [Type] => Profile [Role] => User [Some Number] => 1 [Some Boolean] => true It's not crucial that the boolean be included, so if that adds too much complexity, I'd rather just know how to deal with the others for now. The second goal is to be able to select the value node (<string>, <integer>,etc) so that I can change the value. I would need to select it based on the text value of the preceding key element. I think the following XPath should work: //key[.=$keyname]/following-sibling[1] But I'm not sure. Basically, this whole system that Apple uses seems logical, but totally contrary to the XML is supposed to work. If I ran the world, the original XML would look more like: <dict type="array"> <value key="Name" type="string">Joe Smith</value> <value key="Type" type="string">Profile</value> <value key="Role type="string">User</value> <value key="Some Number" type="integer">1</value> <value key="Some Boolean" type="boolean">true</value> </dict> But since it is fairly logical, I am wondering if I'm missing some obvious way of handling it.

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  • Subtracting Delphi Time Ranges from a Date Range, Calculate Remaining Time

    - by Anagoge
    I'm looking for an algorithm that will help calculate a workday working time length. It would have an input date range and then allow subtracting partially or completely intersecting time range slices from that date range and the result would be the number of minutes (or the fraction/multiple of a day) left in the original date range, after subtracting out the various non-working time slices. For Example: Input date range: 1/4/2010 11:21 am - 1/5/2010 3:00 pm Subtract out any partially or completely intersecting slices like this: Remove all day Sunday Non-Sundays remove 11:00 - 12:00 Non-Sundays remove time after 5:00 pm Non-Sundays remove time before 8:00 am Non-Sundays remove time 9:15 - 9:30 am Output: # of minutes left in the input date range I don't need anything overly-general. I could hardcode the rules to simplify the code. If anyone knows of sample code or a library/function somewhere, or has some pseudo-code ideas, I'd love something to start with. I didn't see anything in DateUtils, for example. Even a basic function that calculates the number of minutes of overlap in two date ranges to subtract out would be a good start.

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  • How to implement square root and exponentiation on arbitrary length numbers?

    - by tomp
    I'm working on new data type for arbitrary length numbers (only non-negative integers) and I got stuck at implementing square root and exponentiation functions (only for natural exponents). Please help. I store the arbitrary length number as a string, so all operations are made char by char. Please don't include advices to use different (existing) library or other way to store the number than string. It's meant to be a programming exercise, not a real-world application, so optimization and performance are not so necessary. If you include code in your answer, I would prefer it to be in either pseudo-code or in C++. The important thing is the algorithm, not the implementation itself. Thanks for the help.

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  • Monitoring .NET ASP.NET Applications

    - by James Hollingworth
    I have a number of applications running on top of ASP.NET I want to monitor. The main things I care about are: Exceptions: We currently some custom code which will email us when an exception occurs. If the application is failing hard it will crash our outlook... I know (and use) elmah which partly solves the problem however it is still just a big table of exceptions with a pretty(ish) UI. I want something that makes sense of all of these exceptions (e.g. groups exceptions, alerts when new ones occur, tells me what the common ones are that I should fix, etc) Logging: We currently log to files which are then accessible via a shared folder which dev's grep & tail. Does anyone know of better ways of presenting this information. In an ideal world I want to associate it with exceptions. Performance: Request times, memory usage, cpu, etc. whatever stats I can get I'm guessing this is probably going to be solved by a number of tools, has anyone got any suggestions?

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  • Multiple ports listed in SQL Server connection string

    - by BBlake
    I have a legacy VB6 app where the servername, databasename, username, etc are defined in an INI file, but the port number for the connection string (the default 1433) is hard coded in the app. It's being moved to a new sql server back end that runs off a different port number. I'm trying to avoid having to alter and recompile the application which entails signifigant retesting, documentation, etc. I tried altering the INI file so that for the new server I have put in: SERVERNAME\INSTANCE,NEWPORTNUMBER This effectively builds the connection with Data Source = SERVERNAME\INSTANCE,NEWPORTNUMBER,1433; This appears to work correctly as it connects to the database when I run the app. It appears to me that the ,1433 portion is being ignored. Is this a valid assumption or will this cause me some problem I'm not seeing here?

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  • How to update assmebly version info with new build and revision during build?

    - by hrushikesh
    I have to update the build number in assembly version of assemblyinfo.cs file. I have written a custom tasks which updates all the assmeblyinfo.cs under a solution before starting build. But when i change this file and try to build then some of my dlls which has reference of other dlls not able to compile as they dont find the specific version assembly. I have some files which uses strong name assembly also. Not sure how to update their version. I have tried setting specific version to false,but still same error is coming. Can you anybody tell me the good way to update the assemblyinfo.cs with incremental build number? P.S. i am using NANT tasks for automating by builds.

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  • Maven 2: How to package current project version in a WAR file?

    - by Tom van Zummeren
    I am using Maven 2 to build my Java project and I am looking for a way to present the current version number of the pom.xml to the user (using a Servlet or JSP for example). As far as I can see, the best way would be that Maven packages the version number as a text file into the WAR. This allows me to read the version from that file and present it the way I want. Does anyone know of a plugin that can do something like that for me? Maybe the WAR plugin can be configured to do so? Or maybe using some other approach all together?

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  • devise register confirmation

    - by mattherick
    hello! i have a user and an admin role in my project. i created my authentification with devise, really nice and goot tool for handling the authentification. in my admin role i don´t have any confirmation or something like that. it is really simple and doesn´t make problems. but in my user model i have following things: model: devise :database_authenticatable, :confirmable, :recoverable, :rememberable, :trackable, :validatable, :timeoutable, :registerable # Setup accessible (or protected) attributes for your model attr_accessible :email, :username, :prename, :surname, :phone, :street, :number, :location, :password, :password_confirmation and few validations, but they aren´t relevant this time. my migration looks like following one: class DeviseCreateUsers < ActiveRecord::Migration def self.up create_table(:users) do |t| t.database_authenticatable :null = false t.confirmable t.recoverable t.rememberable t.trackable t.timeoutable t.validateable t.string :username t.string :prename t.string :surname t.string :phone t.string :street t.integer :number t.string :location t.timestamps end add_index :users, :email, :unique => true add_index :users, :confirmation_token, :unique => true add_index :users, :reset_password_token, :unique => true add_index :users, :username, :unique => true add_index :users, :prename, :unique => false add_index :users, :surname, :unique => false add_index :users, :phone, :unique => false add_index :users, :street, :unique => false add_index :users, :number, :unique => false add_index :users, :location, :unique => false end def self.down drop_table :users end end into my route.rb I added following statements: map.devise_for :admins map.devise_for :users, :path_names = { :sign_up = "register", :sign_in = "login" } map.root :controller = "main" and now my problem.. if I register a new user, I fill in all my data in the register form and submit it. After that I get redirected to the controller main with the flash-notice "You have signed up successfully." And I am logged in. But I don´t want to be logged in, because I don´t have confirmed my new user account yet. If I open the console I see the last things in the logs and there I see the confirmation-mail and the text and all stuff, but I am already logged in... I can´t explain why, ... does somebody of you have an idea? If I copy out the confirmation-token from the logs and confirm my account, I can log in, but if I don´t confirm, I also can log in..

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  • Diagonal Output of Assembly programe

    - by Yousuf Umar
    i have this assembly programe and i want to diagonal ouptut of this programe but i dont know how to put tabspace in assembly section .text global _start ;must be declared for using gcc _start: ;tell linker entry point mov edx, len ;message length mov ecx, msg ;message to write mov ebx, 1 ;file descriptor (stdout) mov eax, 4 ;system call number (sys_write) int 0x80 ;call kernel mov eax, 1 ;system call number (sys_exit) int 0x80 ;call kernel section .data msg db 'Y',10,'O',10,'U',10,'S',10,'U',10,'F' ;our dear string len equ $ - msg ;length of our dear string output of my programe is Y O U S U F output shoud like this Y O U S U F or is there any other way to write this programe and get this output

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  • How to retrieve row count of one-to-many relation while also include original entity?

    - by kaa
    Say I have two entities Foo and Bar where Foo has-many Bar's, class Foo { int ImportantNumber { get; set; } IEnumerable<Bar> Bars { get; set; } } class FooDTO { Foo Foo { get; set; } int BarCount { get; set; } } How can I efficiently sum up the number of Bars per Foo in a DTO using a single query, preferrably only with the Criteria interface. I have tried any number of ways to get the original entity out of a query with ´SetProjection´ but no luck. The current theory is to do something like SELECT Foo.*, BarCounts.counts FROM Foo LEFT JOIN ( SELECT fooId, COUNT(*) as counts FROM Bar GROUP BY fooId ) AS BarCounts ON Foo.id=BarCounts.fooId but with Criterias, and I just can't seem to figure out how.

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  • Using Queries with Coherence Read-Through Caches

    - by jpurdy
    Applications that rely on partial caches of databases, and use read-through to maintain those caches, have some trade-offs if queries are required. Coherence does not support push-down queries, so queries will apply only to data that currently exists in the cache. This is technically consistent with "read committed" semantics, but the potential absence of data may make the results so unintuitive as to be useless for most use cases (depending on how much of the database is held in cache). Alternatively, the application itself may manually "push down" queries to the database, either retrieving results equivalent to querying the cache directly, or may query the database for a key set and read the values from the cache (relying on read-through to handle any missing values). Obviously, if the result set is too large, reading through the cache may cause significant thrashing. It's also worth pointing out that if the cache is asynchronously synchronized with the database (perhaps via database change listener), that an application may commit a transaction to the database, then generate a key set from the database via a query, then read cache entries through the cache, possibly resulting in a race condition where the application sees older data than it had previously committed. In theory this is not problematic but in practice it is very unintuitive. For this reason it often makes sense to invalidate the cache when updating the database, forcing the next read-through to update the cache.

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  • Bit Flipping in Hex

    - by freyrs
    I have an 8 digit hexadecimal number of which I need certain digits to be either 0 or f. Given the specific place of the digits is there a quick way to generate the hex number with those places "flipped" to f. For example: flip_digits(1) = 0x000000f flip_digits(1,2,4) = 0x0000f0ff flip_digits(1,7,8) = 0xff00000f I'm doing this on an embedded device so I can't call any math libraries, I suspect it can be done with just bit shifts but I can't quite figure out the method. Any sort of solution (Python, C, Pseudocode) will work. Thanks in advance.

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  • I have applied a check for not allowing alphabets.But its not working.....

    - by bhavna raghuvanshi
    import java.util.Scanner; public class Main extends Hashmap{ public static void main(String[] args) { Hashmap hm = new Hashmap(); int x=0; Scanner input = new Scanner(System.in); do{ System.out.print("Enter any integer value between 1 to 12: "); x = input.nextInt(); }while(x<=0 || x>12); Scanner sc = new Scanner(System.in); //int number; do { while (!sc.hasNextInt()) { System.out.println("That's not a number!"); sc.next(); } x = sc.nextInt(); }while(x>=0); String month = hm.getEntry(x); System.out.println(month); } } here I need to restrict user from entering an alphabet.But its not working. pls help...

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  • Forcing positive sign on double in .Net String.Format

    - by Max Yaffe
    Context: .Net, C# I want to print a complex number made from two doubles. The sign needs to show on the imaginary part. I'd like to use the default double formatting for each part to minimize the number of characters. I tried using String.Format("{0:+G;-G}{1:+G;-G}j", real, imaginary) but this ended up printing: "+G-Gj". Not quite what I wanted. Is there any way to do this using the G specifier or do I need to do a custom format which would sacrifice auto-switching the exponent, e.g. {1:+#.######e###;-#.######e###}j"

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  • I need to generate credit card surrogates (tokens) that are format preserving.

    - by jammer59
    For an eCommerce application I need to take a credit card and use the real card for passing through to a payment gateway but I need to store, and return to the transaction initiator, a surrogate that is format preserving. Specifically, this means: 1) The number of digits in the surrogate is the same as the real card number (PAN). 2) The issuer type part of the card -- the initial 1,2 or 4 digits remains the same in the surrogate as in the original PAN. 3) The final 4 digits of the surrogate remain the same (for customer service purposes.) 4) The surrogate passes the Luhn mod10 check for a syntactially valid credit card. I can readily handle requirements 1-3 but #4 has me completely stumped! The final implementation will be either t-sql or c#. Any ideas?

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  • Excel - Counting unique values that meet multiple criteria

    - by wotaskd
    I'm trying to use a function to count the number of unique cells in a spreadsheet that, at the same time, meet multiple criteria. Given the following example: A B C QUANT STORE# PRODUCT 1 75012 banana 5 orange 6 56089 orange 3 89247 orange 7 45321 orange 2 apple 4 45321 apple In the example above, I need to know how many unique stores with a valid STORE# have received oranges OR apples. In the case above, the result should be 3 (stores 56089, 89247 and 45321). This is how I started to try solving the problem: =SUM(IF(FREQUENCY(B2:B9,B2:B9)>0,1)) The above formula will yield the number of unique stores with a valid store#, but not just the ones that have received oranges or bananas. How can I add that extra criteria?

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  • How do I remove specific numbers from a string?

    - by user1666900
    I have this string in PHP Hopelessly Incredible |SPG:M| 766 STEAM_0:1:20130600 " banned "A Blatantly Obvious Hacker 740 STEAM_0:1:55386073 " (minutes "0") (reason "Multi-Hack") The Format of the string is: Name1 Number(0-3 digits) Steam_0:x:xxxx offense (banned/kicked/mute etc) Name2 Number(0-3 digits) Steam_0:x:xxxx time reason My goal is to remove the values 766 and 740 because it is just garbage. Those values can have single, double, and triple digits. The next step would be to strip STEAM_0:1:20130600 and STEAM_0:1:55386073 out of the string and capture it in a new variable. The only constant is STEAM_0: the rest can change. I am still learning regex but I fear this is a bit complicated for me to do. Some guidance would be most appreciative.

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  • Check if row already exists, if so tell the referenced table the id

    - by flhe
    Let's assume I have a table magazine: CREATE TABLE magazine ( magazine_id integer NOT NULL DEFAULT nextval(('public.magazine_magazine_id_seq'::text)::regclass), longname character varying(1000), shortname character varying(200), issn character varying(9), CONSTRAINT pk_magazine PRIMARY KEY (magazine_id) ); And another table issue: CREATE TABLE issue ( issue_id integer NOT NULL DEFAULT nextval(('public.issue_issue_id_seq'::text)::regclass), number integer, year integer, volume integer, fk_magazine_id integer, CONSTRAINT pk_issue PRIMARY KEY (issue_id), CONSTRAINT fk_magazine_id FOREIGN KEY (fk_magazine_id) REFERENCES magazine (magazine_id) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION ); Current INSERTS: INSERT INTO magazine (longname,shotname,issn) VALUES ('a long name','ee','1111-2222'); INSERT INTO issue (fk_magazine_id,number,year,volume) VALUES (currval('magazine_magazine_id_seq'),'8','1982','6'); Now a row should only be inserted into 'magazine', if it does not already exist. However if it exists, the table 'issue' needs to get the 'magazine_id' of the row that already exists in order to establish the reference. How can i do this? Thx in advance!

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  • Tool to convert inline C' into a code behind

    - by Jon Jones
    Hi I have a number of legacy web controls (ascx) that contains huge amounts of inline C#. The forms contain a number of repeated and duplicate code. Our first plan is to move the code into code behinds per file, then refactor etc... were doing this to upgrade the client to the latest version of their cms At the moment we are going to have to manually copy and paste hundreds files, convert the namespace client-side imports into usings, etc... does anybody PLEASE know of a tool that can do the majority of this work for us ? Thanks

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