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  • Hyper-v and sql server connections for web apps

    - by Rick Ratayczak
    I have a physical machine running win8, and two VMs in hyper-v client: 1 web server, 1 sql server. The web server works fantastic. The sql is the one that is giving me the problem. I can connect to it with server explorer in visual studio or management studio just fine, and it's blazing fast. The problem happens when I use the same connection string I am using in visual studio server explorer in the web.config for an app. data source=VMSQL1;initial catalog=OtherShell;persist security info=True;user id=OtherShell;password=****;network library=dbmssocn;MultipleActiveResultSets=True;App=EntityFramework I made sure it was also using tcp-ip, but it doesn't connect with or without the network library part of the connection string. A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) This is driving my batty for the last two days, any ideas? It fails from the web vm too, but works in management studio with the same connection string.

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  • Replace a SQL Server query with another before execution

    - by Kiranu
    I am trying to work with a legacy application in SQL Server which at some point does the following query SELECT serverproperty('EngineEdition') as sqledition The server replies with 2 (which is the correct edition), but the application closes since the app demands to be run over SQL Server Express which is 4. We don't have access to the code and the developer is long gone. Is there a way to configure SQL Server so that when this query is received it simply returns 4 and not the value of the property? Thanks

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  • Configuring SQL Server Express 2005

    - by MrTognio
    What's the proper way to configure SQL Server Express 2005 so that it can allow for a number of clients to get connected to the server? I have my application running both in the server machine and the client machines. Given the nature of my application, clients are the branches geographically distant from each other, and the server itself. Every operation the client records must be reported to the server, because the server needs total control over the usage and production. But, what should I consider when configuring the connection in both sides, the server and the client? I'm not as used to SQL Server, I'm a beginner, however through SQL Server Configuration Manager I have set the main options without success. The problem seems to be related to trusted connections even though I have set it to support both windows and SQL Server authentication. When the client tries to connect to the server using windows authentication it displays no table; when it tries to communicate using a password (SQL Server authentication), tables are successfully displayed but no access is allowed... Thanx in advance!

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  • Experience with asymmetrical (non-identical hardware) SQL Server 2005 / Win 2003 cluster

    - by user24161
    I am reasonably good at dealing with SQL Server clusters; I am wondering if folks have experience, good or bad, using a mix of different models of servers from the same vendor in one SQL 2005 cluster. Suppose: I have one more powerful, more RAM, more shizzle box and one less powerful, less memory, less shizzle box bound together in a 2-node cluster. These would be HP DL380 and 580 machines (not that it should matter) I understand AND automate the process of managing memory for each SQL instance, so there's no memory contention when SQL instances fail over. Basically I am thinking a CLR proc will monitor the instances and self-regulate memory caps on each instance, so that they won't page or step on one another. I get the fact the instances might be slower and or under memory pressure if they share a "lesser" node, and that's OK. The business can deal with a slower instance in a server-problem scenario. Reasonable? Any "gotchas" to watch out for? More info 10/28: doing some experiments with a test cluster I find that reconfiguring max/min memory is OK PROVIDED the instance isn't already under memory pressure. If I torture the system with a huge query that demands a big chunk of RAM, and simultaneously adjust the memory allocation to a smaller value than what is being actively used, it's possible to run the instance out of memory and have it halt and restart itself (unhappy situation). Many ugly out-of-memory messages in the error log, crashing, burning... It's an extreme case, but good to know. Seems, then, that it would only be really safe to set this on startup of the instance, as in have a startup script that says "I am on node1, so my RAM settings are X or I am on node two, so they are Y," like this: http://sqlblog.com/blogs/aaron_bertrand... Update: I am testing a SQL Agent + PowerShell solution described in more detail here.

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  • Hosting company that does Linux VPS and MS SQL

    - by danielmcq
    I'm looking for hosted solutions but there are so many companies that finding the right one using a Google search is a bit overwhelming. Ideally I would like a hosting company which has following options: -Linux VPSs - Individual VPSs should be fairly cheap since I plan on putting one or two services per VPS i.e web server on one (httpd and ColdFusion), an SVN server on another, etc. -Managed MS SQL databases - My company already has data in MS SQL databases and a lot of ColdFusion code written that has MS SQL specific commands in it. -Individually purchased dedicated IP addresses -Preferably located in the North America region My plan would be to setup one Linux VPS as a gateway/firewall/VPN server and have all of my traffic routed through so that my other servers would not use of bandwidth by talking to each other. The trick is also finding a company that does Linux VPS AND MS SQL databases. Does anybody know of any hosting companies offer what I'm looking for? Let me know if I need to add more details.

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  • unlock database files when SQL server is idle

    - by Andy
    In my development/test environment on my laptop, I can't back up the SQL server database files because the file handles are kept permanently open by SQL server (VSS doesn't work because the drive is truecrypted) I was hoping there may be some setting in SQL server that can make it unlock the data files after a certain period of inactivity and automatically open them again on demand, but I can't find anything. I don't really want to be dumping the database out every night because it's only a development environment. apart from stopping sql server before I do the backup is there any other solution?

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  • SQL Server 2000 Enterprise Edition - Login Fail for User (computer Name)/Guest

    - by Nazmuzzaman Manna
    Hi: Subject: SQL Server 2000 Enterprise Edition, windows XP Log-in fail for odbc sql server user computer name/guest I am connecting for several computer with the VB6 application with following connection string "PROVIDER=MSDASQL;driver={SQL Server};server=Computer Name.;uid=;pwd=;database=Test Name;" BUT, just Three Computer not Log-in. This three (connected with each other) are completely separate in other Room. I checked all possible options. Besides, which option is missing??? Please Help me...

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  • SQL server text

    - by Nick P
    I will be taking an independent study class on SQL server management. I will have to configure SQL Server 2008 on a Windows Server 2008 system. I was wondering if anyone could suggest decent text for configuration/administration of SQL Server 2008. The Murach text doesn't look like it will take me far.

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  • Using SQL Source Control and Vault Professional Part 4

    - by Ajarn Mark Caldwell
    Two weeks ago I upgraded our installation of Fortress to the latest version, which is now named Vault Professional.  This is the version of Vault (i.e. Vault Standard 5.1 / Vault Professional 5.1) that will be officially supported with Red-Gate SQL Source Control 2.1.  While the folks at Red-Gate did a fantastic job of working with me to get SQL Source Control to work with the older Fortress version, we weren’t going to just sit on that.  There are a couple of things that Vault Professional cleaned up for us, such as improved integration with Visual Studio 2010, so it was a win all around. Shortly after that upgrade, I received notice from Red-Gate that they had a new Early Access version of SQL Source Control available that included the ability to source control static data.  The idea here is that you probably have a few fairly static lookup tables in your system, and those data values are similar in concept to source code, and should be versioned in your source control management system also.  I agree with this, but please be wise…somebody out there is bound to try to use this feature as their disaster recovery for their entire database, and that is NOT the purpose.  First off, you should never have your PROD (or LIVE, whatever you call it) system attached to source control.  Source Control is for development, not for PROD systems.  Second, use the features that are intended for this purpose, such as BACKUP and RESTORE. Laying that tangent aside, it is great that now you can include these critical values in your repository and make them part of a deployment process.  As you would guess, SQL Source Control uses SQL Data Compare to create the data change scripts just like it uses SQL Compare to create the schema change scripts.  Once again, they did a very good job with the integration to their other products.  At this point we are really starting to see some good payback on our investment in the full SQL Developer Bundle.  Those products were worth the investment back when we only used them sporadically for troubleshooting and DBA analysis, but now with SQL Source Control, they are becoming everyday-use products for the development team. I like this software (SQL Source Control) so much that I am about to break my own rules and distribute it to my team to use even though it is still in beta.  This is the first time that I have approved the use of any beta software in a production scenario (actively building our next versions of internal software) but I predict that the usability and productivity gain of using SQL Source Control over manual scripting is worth the risk.  Of course, I have also put this beta software through its paces pretty well to be comfortable with it, and Red-Gate has proven their responsiveness to issues that came up in my early beta testing, and so I am willing to bet on their continued support.  Likewise, SourceGear, the maker of Vault Professional, has proven itself to me as well, and so the combination of SQL Source Control with Vault Professional is the new standard for my development team.

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  • Java: micro-optimizing array manipulation

    - by Martin Wiboe
    Hello all, I am trying to make a Java port of a simple feed-forward neural network. This obviously involves lots of numeric calculations, so I am trying to optimize my central loop as much as possible. The results should be correct within the limits of the float data type. My current code looks as follows (error handling & initialization removed): /** * Simple implementation of a feedforward neural network. The network supports * including a bias neuron with a constant output of 1.0 and weighted synapses * to hidden and output layers. * * @author Martin Wiboe */ public class FeedForwardNetwork { private final int outputNeurons; // No of neurons in output layer private final int inputNeurons; // No of neurons in input layer private int largestLayerNeurons; // No of neurons in largest layer private final int numberLayers; // No of layers private final int[] neuronCounts; // Neuron count in each layer, 0 is input // layer. private final float[][][] fWeights; // Weights between neurons. // fWeight[fromLayer][fromNeuron][toNeuron] // is the weight from fromNeuron in // fromLayer to toNeuron in layer // fromLayer+1. private float[][] neuronOutput; // Temporary storage of output from previous layer public float[] compute(float[] input) { // Copy input values to input layer output for (int i = 0; i < inputNeurons; i++) { neuronOutput[0][i] = input[i]; } // Loop through layers for (int layer = 1; layer < numberLayers; layer++) { // Loop over neurons in the layer and determine weighted input sum for (int neuron = 0; neuron < neuronCounts[layer]; neuron++) { // Bias neuron is the last neuron in the previous layer int biasNeuron = neuronCounts[layer - 1]; // Get weighted input from bias neuron - output is always 1.0 float activation = 1.0F * fWeights[layer - 1][biasNeuron][neuron]; // Get weighted inputs from rest of neurons in previous layer for (int inputNeuron = 0; inputNeuron < biasNeuron; inputNeuron++) { activation += neuronOutput[layer-1][inputNeuron] * fWeights[layer - 1][inputNeuron][neuron]; } // Store neuron output for next round of computation neuronOutput[layer][neuron] = sigmoid(activation); } } // Return output from network = output from last layer float[] result = new float[outputNeurons]; for (int i = 0; i < outputNeurons; i++) result[i] = neuronOutput[numberLayers - 1][i]; return result; } private final static float sigmoid(final float input) { return (float) (1.0F / (1.0F + Math.exp(-1.0F * input))); } } I am running the JVM with the -server option, and as of now my code is between 25% and 50% slower than similar C code. What can I do to improve this situation? Thank you, Martin Wiboe

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  • Optimize css vs Google page speed is messing with me

    - by The Disintegrator
    I'm using google page speed and it's telling me my css is inefficient... Very inefficient rules (good to fix on any page): * table.fancy thead td Tag key with 2 descendant selectors and Class overly qualified with tag * table.fancy tfoot td Tag key with 2 descendant selectors and Class overly qualified with tag The css rules are table.fancy {border: 1px solid white; padding:5px} table.fancy td {background:#656165} table.fancy thead td, table.fancy tfoot td {background:#767276} I want the header and footer in a different background color than the body of the table (a data table) On what grounds this is inefficient? How to make it more efficient? I will not add a class to the thead and tfoot for googles's sake.

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  • LINQ to SQL : Too much CPU Usage: What happens when there are multiple users.

    - by soldieraman
    I am using LINQ to SQL and seeing my CPU Usage sky rocketting. See below screenshot. I have three questions What can I do to reduce this CPU Usage. I have done profiling and basically removed everything. Will making every LINQ to SQL statement into a compiled query help? I also find that even with compiled queries simple statements like ByID() can take 3 milliseconds on a server with 3.25GB RAM 3.17GHz - this will just become slower on a less powerful computer. Or will the compiled query get faster the more it is used? The CPU Usage (on the local server goes to 12-15%) for a single user will this multiply with the number of users accessing the server - when the application is put on a live server. i.e. 2 users at a time will mean 15*2 = 30% CPU Usage. If this is the case is my application limited to maximum 4-5 users at a time then. Or doesnt LINQ to SQL .net share some CPU usage.

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  • SQL Compact error: Unable to load DLL 'sqlceme35.dll'. The specified module could not be found

    - by Ciaran Bruen
    Hi - I'm developing a Winforms application using Visual Studio 2008 C# that uses a SQL compact 3.5 database on the client. The client will most likely be 32 bit XP or Vista machines. I'm using a standard Windows Installer project that creates an msi file and setup.exe to install the app on a client machine. I'm new to SQL compact so I haven't had to distribute a client database like this before now. When I run the setup.exe (on new Windows XP 32 bit with SP2 and IE 7) it installs fine but when I run the app I get the error below: Unable to load DLL 'sqlceme35.dll'. The specified module could not be found I spent a few hours searching this error already but all I can find are issues relating to installing on 64 bit Windows, none relating to normal 32 bit that I'm using. The install app copies the all the dependant files that it found into the specified install directory, including the System.Data.SqlServerCe.dll file (assembly version 3.5.1.0). The database file is in a directory called 'data' off the application directory, and the connection string for it is <add name="Tickets.ieOutlet.Properties.Settings.TicketsLocalConnectionString" connectionString="Data Source=|DataDirectory|\data\TicketsLocal.sdf" providerName="Microsoft.SqlServerCe.Client.3.5" /> Some questions I have: should the app be able to find the dll if it's in the same directory i.e. local to the app, or do I need to install it in the GAC? (If so cam I use the Windows Installer to install a dll in the GAC?) is there anything else I need to distribute with the app in order to use a Sql Compact database? there are other dlls also such as MS interop for exporting data to Excel on the client. Do these need to be installed in the GAC or will locating them in the application directory suffice? TIA, Ciaran.

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  • Anybody seen this behavior with Sql Server Reporting Services, a 64bit OS and an Oracle datasource?

    - by dkackman
    I'm working on a Sql Server Reporting Services solution that queries across both a Sql Server data source and an Oracle 10g data source. My dev box is Windows 7 64bit with Sql Server 2008R2 and I'm hosting IIS7 and SSRS on that system for development; using VS.NET for designing the reports. I have been having errors when running the report where SSRS complains about loading the 32 bit Oracle client in a 64bit process. There a number of threads out there about how to solve that. The thing is, they all come down to making sure you have the 64bit Oracle, client which I do. The weird chain of events I have goes like this: Create initial Oracle datasource and wire up report (it works) Edit Oracle datasource connection (it stops working with BadImageFormatException 32bit/64bit error message) uninstall and reinstall Oracle client (it works) Edit Oracle connection again (it stops working with BadImageFormatException 32bit/64bit error message) So short of reinstalling the client every time I change the connection string I am at a complete loss. Has anybody seen this sort of behavior? And if so what the heck am I doing wrong?

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  • Write a compiler for a language that looks ahead and multiple files?

    - by acidzombie24
    In my language I can use a class variable in my method when the definition appears below the method. It can also call methods below my method and etc. There are no 'headers'. Take this C# example. class A { public void callMethods() { print(); B b; b.notYetSeen(); public void print() { Console.Write("v = {0}", v); } int v=9; } class B { public void notYetSeen() { Console.Write("notYetSeen()\n"); } } How should I compile that? what i was thinking is: pass1: convert everything to an AST pass2: go through all classes and build a list of define classes/variable/etc pass3: go through code and check if there's any errors such as undefined variable, wrong use etc and create my output But it seems like for this to work I have to do pass 1 and 2 for ALL files before doing pass3. Also it feels like a lot of work to do until I find a syntax error (other than the obvious that can be done at parse time such as forgetting to close a brace or writing 0xLETTERS instead of a hex value). My gut says there is some other way. Note: I am using bison/flex to generate my compiler.

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  • PostgreSQL - Why are some queries on large datasets so incredibly slow

    - by Brad Mathews
    Hello, I have two types of queries I run often on two large datasets. They run much slower than I would expect them to. The first type is a sequential scan updating all records: Update rcra_sites Set street = regexp_replace(street,'/','','i') rcra_sites has 700,000 records. It takes 22 minutes from pgAdmin! I wrote a vb.net function that loops through each record and sends an update query for each record (yes, 700,000 update queries!) and it runs in less than half the time. Hmmm.... The second type is a simple update with a relation and then a sequential scan: Update rcra_sites as sites Set violations='No' From narcra_monitoring as v Where sites.agencyid=v.agencyid and v.found_violation_flag='N' narcra_monitoring has 1,700,000 records. This takes 8 minutes. The query planner refuses to use my indexes. The query runs much faster if I start with a set enable_seqscan = false;. I would prefer if the query planner would do its job. I have appropriate indexes, I have vacuumed and analyzed. I optimized my shared_buffers and effective_cache_size best I know to use more memory since I have 4GB. My hardware is pretty darn good. I am running v8.4 on Windows 7. Is PostgreSQL just this slow? Or am I still missing something? Thanks! Brad

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  • Optimizing mathematics on arrays of floats in Ada 95 with GNATC

    - by mat_geek
    Consider the bellow code. This code is supposed to be processing data at a fixed rate, in one second batches, It is part of an overal system and can't take up too much time. When running over 100 lots of 1 seconds worth of data the program takes 35 seconds; or 35%. How do I improce the code to get the processing time down to a minimum? The code will be running on an Intel Pentium-M which is a P3 with SSE2. package FF is new Ada.Numerics.Generic_Elementary_Functions(Float); N : constant Integer := 820; type A is array(1 .. N) of Float; type A3 is array(1 .. 3) of A; procedure F(state : in out A3; result : out A3; l : in A; r : in A) is s : Float; t : Float; begin for i in 1 .. N loop t := l(i) + r(i); t := t / 2.0; state(1)(i) := t; state(2)(i) := t * 0.25 + state(2)(i) * 0.75; state(3)(i) := t * 1.0 /64.0 + state(2)(i) * 63.0 /64.0; for r in 1 .. 3 loop s := state(r)(i); t := FF."**"(s, 6.0) + 14.0; if t > MAX then t := MAX; elsif t < MIN then t := MIN; end if; result(r)(i) := FF.Log(t, 2.0); end loop; end loop; end;

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  • Optimizing mathematics on arrays of floats in Ada 95 with GNAT

    - by mat_geek
    Consider the bellow code. This code is supposed to be processing data at a fixed rate, in one second batches, It is part of an overal system and can't take up too much time. When running over 100 lots of 1 seconds worth of data the program takes 35 seconds (or 35%), executing this function in a loop. The test loop is timed specifically with Ada.RealTime. The data is pregenerated so the majority of the execution time is definatetly in this loop. How do I improce the code to get the processing time down to a minimum? The code will be running on an Intel Pentium-M which is a P3 with SSE2. package FF is new Ada.Numerics.Generic_Elementary_Functions(Float); N : constant Integer := 820; type A is array(1 .. N) of Float; type A3 is array(1 .. 3) of A; procedure F(state : in out A3; result : out A3; l : in A; r : in A) is s : Float; t : Float; begin for i in 1 .. N loop t := l(i) + r(i); t := t / 2.0; state(1)(i) := t; state(2)(i) := t * 0.25 + state(2)(i) * 0.75; state(3)(i) := t * 1.0 /64.0 + state(2)(i) * 63.0 /64.0; for r in 1 .. 3 loop s := state(r)(i); t := FF."**"(s, 6.0) + 14.0; if t > MAX then t := MAX; elsif t < MIN then t := MIN; end if; result(r)(i) := FF.Log(t, 2.0); end loop; end loop; end; psuedocode for testing create two arrays of 80 random A3 arrays, called ls and rs; init the state and result A3 array record the realtime time now, called last for i in 1 .. 100 loop for j in 1 .. 80 loop F(state, result, ls(j), rs(j)); end loop; end loop; record the realtime time now, called curr output the duration between curr and last

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  • Optimizing MySql query to avoid using "Using filesort"

    - by usef_ksa
    I need your help to optimize the query to avoid using "Using filesort".The job of the query is to select all the articles that belongs to specific tag. The query is: "select title from tag,article where tag='Riyad' AND tag.article_id=article.id order by tag.article_id". the tables structure are the following: Tag table CREATE TABLE `tag` ( `tag` VARCHAR( 30 ) NOT NULL , `article_id` INT NOT NULL , INDEX ( `tag` ) ) ENGINE = MYISAM ; Article table CREATE TABLE `article` ( `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY , `title` VARCHAR( 60 ) NOT NULL ) ENGINE = MYISAM Sample data INSERT INTO `article` VALUES (1, 'About Riyad'); INSERT INTO `article` VALUES (2, 'About Newyork'); INSERT INTO `article` VALUES (3, 'About Paris'); INSERT INTO `article` VALUES (4, 'About London'); INSERT INTO `tag` VALUES ('Riyad', 1); INSERT INTO `tag` VALUES ('Saudia', 1); INSERT INTO `tag` VALUES ('Newyork', 2); INSERT INTO `tag` VALUES ('USA', 2); INSERT INTO `tag` VALUES ('Paris', 3); INSERT INTO `tag` VALUES ('France', 3);

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  • I'm trying to grasp the concept of creating a program that uses a MS SQL database, but I'm used to r

    - by Sergio Tapia
    How can I make a program use a MS SQL server, and have that program work on whatever computer it's installed on. If you've been following my string of questions today, you'd know that I'm making an open source and free Help Desk suite for small and medium businesses. The client application. The client application is a Windows Forms app. On installation and first launch on every client machine, it'll ask for the address of the main Help Desk server. The server. Here I plan to handle all incoming help requests, show them to the IT guys, and provide WCF services for the Client application to consume. My dilemma lies in that, I know how to make the program run on my local machine; but I'm really stumped on how to make this work for everyone who wants to download and install the server bit on their Windows Server. Would I have to make an SQL Script and have it run on the MS SQL server when a user wants to install the 'server' application? Many thanks to all for your valuable time and effort to teach me. It's really really appreciated. :)

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  • How can I make this Java code run faster?

    - by Martin Wiboe
    Hello all, I am trying to make a Java port of a simple feed-forward neural network. This obviously involves lots of numeric calculations, so I am trying to optimize my central loop as much as possible. The results should be correct within the limits of the float data type. My current code looks as follows (error handling & initialization removed): /** * Simple implementation of a feedforward neural network. The network supports * including a bias neuron with a constant output of 1.0 and weighted synapses * to hidden and output layers. * * @author Martin Wiboe */ public class FeedForwardNetwork { private final int outputNeurons; // No of neurons in output layer private final int inputNeurons; // No of neurons in input layer private int largestLayerNeurons; // No of neurons in largest layer private final int numberLayers; // No of layers private final int[] neuronCounts; // Neuron count in each layer, 0 is input // layer. private final float[][][] fWeights; // Weights between neurons. // fWeight[fromLayer][fromNeuron][toNeuron] // is the weight from fromNeuron in // fromLayer to toNeuron in layer // fromLayer+1. private float[][] neuronOutput; // Temporary storage of output from previous layer public float[] compute(float[] input) { // Copy input values to input layer output for (int i = 0; i < inputNeurons; i++) { neuronOutput[0][i] = input[i]; } // Loop through layers for (int layer = 1; layer < numberLayers; layer++) { // Loop over neurons in the layer and determine weighted input sum for (int neuron = 0; neuron < neuronCounts[layer]; neuron++) { // Bias neuron is the last neuron in the previous layer int biasNeuron = neuronCounts[layer - 1]; // Get weighted input from bias neuron - output is always 1.0 float activation = 1.0F * fWeights[layer - 1][biasNeuron][neuron]; // Get weighted inputs from rest of neurons in previous layer for (int inputNeuron = 0; inputNeuron < biasNeuron; inputNeuron++) { activation += neuronOutput[layer-1][inputNeuron] * fWeights[layer - 1][inputNeuron][neuron]; } // Store neuron output for next round of computation neuronOutput[layer][neuron] = sigmoid(activation); } } // Return output from network = output from last layer float[] result = new float[outputNeurons]; for (int i = 0; i < outputNeurons; i++) result[i] = neuronOutput[numberLayers - 1][i]; return result; } private final static float sigmoid(final float input) { return (float) (1.0F / (1.0F + Math.exp(-1.0F * input))); } } I am running the JVM with the -server option, and as of now my code is between 25% and 50% slower than similar C code. What can I do to improve this situation? Thank you, Martin Wiboe

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  • What is a data structure for quickly finding non-empty intersections of a list of sets?

    - by Andrey Fedorov
    I have a set of N items, which are sets of integers, let's assume it's ordered and call it I[1..N]. Given a candidate set, I need to find the subset of I which have non-empty intersections with the candidate. So, for example, if: I = [{1,2}, {2,3}, {4,5}] I'm looking to define valid_items(items, candidate), such that: valid_items(I, {1}) == {1} valid_items(I, {2}) == {1, 2} valid_items(I, {3,4}) == {2, 3} I'm trying to optimize for one given set I and a variable candidate sets. Currently I am doing this by caching items_containing[n] = {the sets which contain n}. In the above example, that would be: items_containing = [{}, {1}, {1,2}, {2}, {3}, {3}] That is, 0 is contained in no items, 1 is contained in item 1, 2 is contained in itmes 1 and 2, 2 is contained in item 2, 3 is contained in item 2, and 4 and 5 are contained in item 3. That way, I can define valid_items(I, candidate) = union(items_containing[n] for n in candidate). Is there any more efficient data structure (of a reasonable size) for caching the result of this union? The obvious example of space 2^N is not acceptable, but N or N*log(N) would be.

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  • Please help optimizing a long running query (left outer join, with 2 subqueries)

    - by 46and2
    Hi all. The query I need help with is: SELECT d.bn, d.4700, d.4500, ... , p.`Activity Description` FROM ( SELECT temp.bn, temp.4700, temp.4500, .... FROM `tdata` temp GROUP BY temp.bn HAVING (COUNT(temp.bn) = 1) ) d LEFT OUTER JOIN ( SELECT temp2.bn, max(temp2.FPE) AS max_fpe, temp2.`Activity Description` FROM `pdata` temp2 GROUP BY temp2.bn ) p ON p.bn = d.bn; The ... represents other fields that aren't really important to solving this problem. The issue is on the the second subquery - it is not using the index I have created and I am not sure why, it seems to be because of the way TEXT fields are handled. The first subquery uses the index I have created and runs quite snappy, however an explain on the second shows a 'Using temporary; Using filesort'. Please see the indexes I have created in the below table create statements. Can anyone help me optimize this? By way of quick explanation the first subquery is meant to only select records that have unique bn's, the second, while it looks a bit wacky (with the max function there which is not being used in the result set) is making sure that only one record from the right part of the join is included in the result set. My table create statements are CREATE TABLE `tdata` ( `BN` varchar(15) DEFAULT NULL, `4000` varchar(3) DEFAULT NULL, `5800` varchar(3) DEFAULT NULL, .... KEY `BN` (`BN`), KEY `idx_t3010`(`BN`,`4700`,`4500`,`4510`,`4520`,`4530`,`4570`,`4950`,`5000`,`5010`,`5020`,`5050`,`5060`,`5070`,`5100`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 CREATE TABLE `pdata` ( `BN` varchar(15) DEFAULT NULL, `FPE` datetime DEFAULT NULL, `Activity Description` text, .... KEY `BN` (`BN`), KEY `idx_programs_2009` (`BN`,`FPE`,`Activity Description`(100)) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 Thanks!

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  • How to log slow queries in shared hosting MySQL?

    - by tomaszs
    I have a shared hosting where I have my website and MySQL database. I've installed a open source script for statistics (phpMyVisites) and it started to work very slow lately. It's written using some kind of framework and has many PHP files. I know that to find slow queries I can use slow query log functionality in MySQL. But on this shared hosting I can not use this method because I can not change my.cnf. I don't want to change my statistics script to other and I don't want to mess around with all files of this script to find out where to put diagnostics code to log queries manually. I would like to do it without changes in PHP code. So my question is: How to log slow queries in these coditions?: Can't change my.cnf to enable slow query log Can't change statistics script to other Don't know how scrpt is written and where mysql commands are issued Can't ask my provider for slow query log Is there any method to do this in simple, easy, fast way?

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