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• SQL SERVER – Weekly Series – Memory Lane – #039

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 FQL – Facebook Query Language Facebook list following advantages of FQL: Condensed XML reduces bandwidth and parsing costs. More complex requests can reduce the number of requests necessary. Provides a single consistent, unified interface for all of your data. It’s fun! UDF – Get the Day of the Week Function The day of the week can be retrieved in SQL Server by using the DatePart function. The value returned by the function is between 1 (Sunday) and 7 (Saturday). To convert this to a string representing the day of the week, use a CASE statement. UDF – Function to Get Previous And Next Work Day – Exclude Saturday and Sunday While reading ColdFusion blog of Ben Nadel Getting the Previous Day In ColdFusion, Excluding Saturday And Sunday, I realize that I use similar function on my SQL Server Database. This function excludes the Weekends (Saturday and Sunday), and it gets previous as well as next work day. Complete Series of SQL Server Interview Questions and Answers Data Warehousing Interview Questions and Answers – Introduction Data Warehousing Interview Questions and Answers – Part 1 Data Warehousing Interview Questions and Answers – Part 2 Data Warehousing Interview Questions and Answers – Part 3 Data Warehousing Interview Questions and Answers Complete List Download 2008 Introduction to Log Viewer In SQL Server all the windows event logs can be seen along with SQL Server logs. Interface for all the logs is same and can be launched from the same place. This log can be exported and filtered as well. DBCC SHRINKFILE Takes Long Time to Run If you are DBA who are involved with Database Maintenance and file group maintenance, you must have experience that many times DBCC SHRINKFILE operations takes a long time but any other operations with Database are relatively quicker. mssqlsystemresource – Resource Database The purpose of resource database is to facilitates upgrading to the new version of SQL Server without any hassle. In previous versions whenever version of SQL Server was upgraded all the previous version system objects needs to be dropped and new version system objects to be created. 2009 Puzzle – Write Script to Generate Primary Key and Foreign Key In SQL Server Management Studio (SSMS), there is no option to script all the keys. If one is required to script keys they will have to manually script each key one at a time. If database has many tables, generating one key at a time can be a very intricate task. I want to throw a question to all of you if any of you have scripts for the same purpose. Maximizing View of SQL Server Management Studio – Full Screen – New Screen I had explained the following two different methods: 1) Open Results in Separate Tab - This is a very interesting method as result pan shows up in a different tab instead of the splitting screen horizontally. 2) Open SSMS in Full Screen - This works always and to its best. Not many people are aware of this method; hence, very few people use it to enhance performance. 2010 Find Queries using Parallelism from Cached Plan T-SQL script gets all the queries and their execution plan where parallelism operations are kicked up. Pay attention there is TOP 10 is used, if you have lots of transactional operations, I suggest that you change TOP 10 to TOP 50 This is the list of the all the articles in the series of computed columns. SQL SERVER – Computed Column – PERSISTED and Storage This article talks about how computed columns are created and why they take more storage space than before. SQL SERVER – Computed Column – PERSISTED and Performance This article talks about how PERSISTED columns give better performance than non-persisted columns. SQL SERVER – Computed Column – PERSISTED and Performance – Part 2 This article talks about how non-persisted columns give better performance than PERSISTED columns. SQL SERVER – Computed Column and Performance – Part 3 This article talks about how Index improves the performance of Computed Columns. SQL SERVER – Computed Column – PERSISTED and Storage – Part 2 This article talks about how creating index on computed column does not grow the row length of table. SQL SERVER – Computed Columns – Index and Performance This article summarized all the articles related to computed columns. 2011 SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Data Warehousing Concepts – Day 21 of 31 What is Data Warehousing? What is Business Intelligence (BI)? What is a Dimension Table? What is Dimensional Modeling? What is a Fact Table? What are the Fundamental Stages of Data Warehousing? What are the Different Methods of Loading Dimension tables? Describes the Foreign Key Columns in Fact Table and Dimension Table? What is Data Mining? What is the Difference between a View and a Materialized View? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Data Warehousing Concepts – Day 22 of 31 What is OLTP? What is OLAP? What is the Difference between OLTP and OLAP? What is ODS? What is ER Diagram? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Data Warehousing Concepts – Day 23 of 31 What is ETL? What is VLDB? Is OLTP Database is Design Optimal for Data Warehouse? If denormalizing improves Data Warehouse Processes, then why is the Fact Table is in the Normal Form? What are Lookup Tables? What are Aggregate Tables? What is Real-Time Data-Warehousing? What are Conformed Dimensions? What is a Conformed Fact? How do you Load the Time Dimension? What is a Level of Granularity of a Fact Table? What are Non-Additive Facts? What is a Factless Facts Table? What are Slowly Changing Dimensions (SCD)? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Data Warehousing Concepts – Day 24 of 31 What is Hybrid Slowly Changing Dimension? What is BUS Schema? What is a Star Schema? What Snow Flake Schema? Differences between the Star and Snowflake Schema? What is Difference between ER Modeling and Dimensional Modeling? What is Degenerate Dimension Table? Why is Data Modeling Important? What is a Surrogate Key? What is Junk Dimension? What is a Data Mart? What is the Difference between OLAP and Data Warehouse? What is a Cube and Linked Cube with Reference to Data Warehouse? What is Snapshot with Reference to Data Warehouse? What is Active Data Warehousing? What is the Difference between Data Warehousing and Business Intelligence? What is MDS? Explain the Paradigm of Bill Inmon and Ralph Kimball. SQL SERVER – Azure Interview Questions and Answers – Guest Post by Paras Doshi – Day 25 of 31 Paras Doshi has submitted 21 interesting question and answers for SQL Azure. 1.What is SQL Azure? 2.What is cloud computing? 3.How is SQL Azure different than SQL server? 4.How many replicas are maintained for each SQL Azure database? 5.How can we migrate from SQL server to SQL Azure? 6.Which tools are available to manage SQL Azure databases and servers? 7.Tell me something about security and SQL Azure. 8.What is SQL Azure Firewall? 9.What is the difference between web edition and business edition? 10.How do we synchronize On Premise SQL server with SQL Azure? 11.How do we Backup SQL Azure Data? 12.What is the current pricing model of SQL Azure? 13.What is the current limitation of the size of SQL Azure DB? 14.How do you handle datasets larger than 50 GB? 15.What happens when the SQL Azure database reaches Max Size? 16.How many databases can we create in a single server? 17.How many servers can we create in a single subscription? 18.How do you improve the performance of a SQL Azure Database? 19.What is code near application topology? 20.What were the latest updates to SQL Azure service? 21.When does a workload on SQL Azure get throttled? SQL SERVER – Interview Questions and Answers – Guest Post by Malathi Mahadevan – Day 26 of 31 Malachi had asked a simple question which has several answers. Each answer makes you think and ponder about the reality of the IT world. Look at the simple question – ‘What is the toughest challenge you have faced in your present job and how did you handle it’? and its various answers. Each answer has its own story. SQL SERVER – Interview Questions and Answers – Guest Post by Rick Morelan – Day 27 of 31 Rick Morelan of Joes2Pros has written an excellent blog post on the subject how to find top N values. Most people are fully aware of how the TOP keyword works with a SELECT statement. After years preparing so many students to pass the SQL Certification I noticed they were pretty well prepared for job interviews too. Yes, they would do well in the interview but not great. There seemed to be a few questions that would come up repeatedly for almost everyone. Rick addresses similar questions in his lucid writing skills. 2012 Observation of Top with Index and Order of Resultset SQL Server has lots of things to learn and share. It is amazing to see how people evaluate and understand different techniques and styles differently when implementing. The real reason may be absolutely different but we may blame something totally different for the incorrect results. Read the blog post to learn more. How do I Record Video and Webcast How to Convert Hex to Decimal or INT Earlier I asked regarding a question about how to convert Hex to Decimal. I promised that I will post an answer with Due Credit to the author but never got around to post a blog post around it. Read the original post over here SQL SERVER – Question – How to Convert Hex to Decimal. Query to Get Unique Distinct Data Based on Condition – Eliminate Duplicate Data from Resultset The natural reaction will be to suggest DISTINCT or GROUP BY. However, not all the questions can be solved by DISTINCT or GROUP BY. Let us see the following example, where a user wanted only latest records to be displayed. Let us see the example to understand further. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Weekly Series – Memory Lane – #037

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Convert Text to Numbers (Integer) – CAST and CONVERT If table column is VARCHAR and has all the numeric values in it, it can be retrieved as Integer using CAST or CONVERT function. List All Stored Procedure Modified in Last N Days If SQL Server suddenly start behaving in un-expectable behavior and if stored procedure were changed recently, following script can be used to check recently modified stored procedure. If a stored procedure was created but never modified afterwards modified date and create a date for that stored procedure are same. Count Duplicate Records – Rows Validate Field For DATE datatype using function ISDATE() We always checked DATETIME field for incorrect data type. One of the user input date as 30/2/2007. The date was sucessfully inserted in the temp table but while inserting from temp table to final table it crashed with error. We had now task to validate incorrect date value before we insert in final table. Jr. Developer asked me how can he do that? We check for incorrect data type (varchar, int, NULL) but this is incorrect date value. Regular expression works fine with them because of mm/dd/yyyy format. 2008 Find Space Used For Any Particular Table It is very simple to find out the space used by any table in the database. Two Convenient Features Inline Assignment – Inline Operations Here is the script which does both – Inline Assignment and Inline Operation DECLARE @idx INT = 0 SET @idx+=1 SELECT @idx Introduction to SPARSE Columns SPARSE column are better at managing NULL and ZERO values in SQL Server. It does not take any space in database at all. If column is created with SPARSE clause with it and it contains ZERO or NULL it will be take lesser space then regular column (without SPARSE clause). SP_CONFIGURE – Displays or Changes Global Configuration Settings If advanced settings are not enabled at configuration level SQL Server will not let user change the advanced features on server. Authorized user can turn on or turn off advance settings. 2009 Standby Servers and Types of Standby Servers Standby Server is a type of server that can be brought online in a situation when Primary Server goes offline and application needs continuous (high) availability of the server. There is always a need to set up a mechanism where data and objects from primary server are moved to secondary (standby) server. BLOB – Pointer to Image, Image in Database, FILESTREAM Storage When it comes to storing images in database there are two common methods. I had previously blogged about the same subject on my visit to Toronto. With SQL Server 2008, we have a new method of FILESTREAM storage. However, the answer on when to use FILESTREAM and when to use other methods is still vague in community. 2010 Upper Case Shortcut SQL Server Management Studio I select the word and hit CTRL+SHIFT+U and it SSMS immediately changes the case of the selected word. Similar way if one want to convert cases to lower case, another short cut CTRL+SHIFT+L is also available. The Self Join – Inner Join and Outer Join Self Join has always been a noteworthy case. It is interesting to ask questions about self join in a room full of developers. I often ask – if there are three kinds of joins, i.e.- Inner Join, Outer Join and Cross Join; what type of join is Self Join? The usual answer is that it is an Inner Join. However, the reality is very different. Parallelism – Row per Processor – Row per Thread – Thread 0  If you look carefully in the Properties window or XML Plan, there is “Thread 0?. What does this “Thread 0” indicate? Well find out from the blog post. How do I Learn and How do I Teach The blog post has raised three very interesting questions. How do you learn? How do you teach? What are you learning or teaching? Let me try to answer the same. 2011 SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 7 of 31 What are Different Types of Locks? What are Pessimistic Lock and Optimistic Lock? When is the use of UPDATE_STATISTICS command? What is the Difference between a HAVING clause and a WHERE clause? What is Connection Pooling and why it is Used? What are the Properties and Different Types of Sub-Queries? What are the Authentication Modes in SQL Server? How can it be Changed? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 8 of 31 Which Command using Query Analyzer will give you the Version of SQL Server and Operating System? What is an SQL Server Agent? Can a Stored Procedure call itself or a Recursive Stored Procedure? How many levels of SP nesting is possible? What is Log Shipping? Name 3 ways to get an Accurate Count of the Number of Records in a Table? What does it mean to have QUOTED_IDENTIFIER ON? What are the Implications of having it OFF? What is the Difference between a Local and a Global Temporary Table? What is the STUFF Function and How Does it Differ from the REPLACE Function? What is PRIMARY KEY? What is UNIQUE KEY Constraint? What is FOREIGN KEY? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 9 of 31 What is CHECK Constraint? What is NOT NULL Constraint? What is the difference between UNION and UNION ALL? What is B-Tree? How to get @@ERROR and @@ROWCOUNT at the Same Time? What is a Scheduled Job or What is a Scheduled Task? What are the Advantages of Using Stored Procedures? What is a Table Called, if it has neither Cluster nor Non-cluster Index? What is it Used for? Can SQL Servers Linked to other Servers like Oracle? What is BCP? When is it Used? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 10 of 31 What Command do we Use to Rename a db, a Table and a Column? What are sp_configure Commands and SET Commands? How to Implement One-to-One, One-to-Many and Many-to-Many Relationships while Designing Tables? What is Difference between Commit and Rollback when Used in Transactions? What is an Execution Plan? When would you Use it? How would you View the Execution Plan? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 11 of 31 What is Difference between Table Aliases and Column Aliases? Do they Affect Performance? What is the difference between CHAR and VARCHAR Datatypes? What is the Difference between VARCHAR and VARCHAR(MAX) Datatypes? What is the Difference between VARCHAR and NVARCHAR datatypes? Which are the Important Points to Note when Multilanguage Data is Stored in a Table? How to Optimize Stored Procedure Optimization? What is SQL Injection? How to Protect Against SQL Injection Attack? How to Find Out the List Schema Name and Table Name for the Database? What is CHECKPOINT Process in the SQL Server? SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Day 12 of 31 How does Using a Separate Hard Drive for Several Database Objects Improves Performance Right Away? How to Find the List of Fixed Hard Drive and Free Space on Server? Why can there be only one Clustered Index and not more than one? What is Difference between Line Feed (\n) and Carriage Return (\r)? Is It Possible to have Clustered Index on Separate Drive From Original Table Location? What is a Hint? How to Delete Duplicate Rows? Why the Trigger Fires Multiple Times in Single Login? 2012 CTRL+SHIFT+] Shortcut to Select Code Between Two Parenthesis Shortcut key is CTRL+SHIFT+]. This key can be very useful when dealing with multiple subqueries, CTE or query with multiple parentheses. When exercised this shortcut key it selects T-SQL code between two parentheses. Monday Morning Puzzle – Query Returns Results Sometimes but Not Always I am beginner with SQL Server. I have one query, it sometime returns a result and sometime it does not return me the result. Where should I start looking for a solution and what kind of information I should send to you so you can help me with solving. I have no clue, please guide me. Remove Debug Button in SSMS – SQL in Sixty Seconds #020 – Video Effect of Case Sensitive Collation on Resultset Collation is a very interesting concept but I quite often see it is heavily neglected. I have seen developer and DBA looking for a workaround to fix collation error rather than understanding if the side effect of the workaround. Switch Between Two Parenthesis using Shortcut CTRL+] Earlier this week I wrote a blog post about CTRL+SHIFT+] Shortcut to Select Code Between Two Parenthesis, I received quite a lot of positive feedback from readers. If you are a regular reader of the blog post, you must be aware that I appreciate the learning shared by readers. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Weekly Series – Memory Lane – #007

  - by pinaldave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Find Stored Procedure Related to Table in Database – Search in All Stored Procedure In 2006 I wrote a small script which will help user  find all the Stored Procedures (SP) which are related to one or more specific tables. This was quite a popular script however, in SQL Server 2012 the same can be achieved using new DMV sys.sql-expression_dependencies. I recently blogged about it over Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies. 2007 SQL SERVER – Versions, CodeNames, Year of Release 1993 – SQL Server 4.21 for Windows NT 1995 – SQL Server 6.0, codenamed SQL95 1996 – SQL Server 6.5, codenamed Hydra 1999 – SQL Server 7.0, codenamed Sphinx 1999 – SQL Server 7.0 OLAP, codenamed Plato 2000 – SQL Server 2000 32-bit, codenamed Shiloh (version 8.0) 2003 – SQL Server 2000 64-bit, codenamed Liberty 2005 – SQL Server 2005, codenamed Yukon (version 9.0) 2008 – SQL Server 2008, codenamed Katmai (version 10.0) 2011 – SQL Server 2008, codenamed Denali (version 11.0) Search String in Stored Procedure Searching sting in the stored procedure is one of the most frequent task developer do. They might be searching for a table, view or any other details. I have written a script to do the same in SQL Server 2000 and SQL Server 2005. This is worth bookmarking blog post. There is an alternative way to do the same as well here is the example. 2008 SQL SERVER – Refresh Database Using T-SQL NO! Some of the questions have a single answer NO! You may want to read the question in the original blog post. I had a great time saying No! SQL SERVER – Delete Backup History – Cleanup Backup History SQL Server stores history of all the taken backup forever. History of all the backup is stored in the msdb database. Many times older history is no more required. Following Stored Procedure can be executed with a parameter which takes days of history to keep. In the following example 30 is passed to keep a history of month. 2009 Stored Procedure are Compiled on First Run – SP taking Longer to Run First Time Is stored procedure pre-compiled? Why the Stored Procedure takes a long time to run for the first time?  This is a very common questions often discussed by developers and DBAs. There is an absolutely definite answer but the question has been discussed forever. There is a misconception that stored procedures are pre-compiled. They are not pre-compiled, but compiled only during the first run. For every subsequent runs, it is for sure pre-compiled. Read the entire article for example and demonstration. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes This is one of the most important performance tuning lesson on my blog. I suggest this weekend you spend time reading them and let me know what you think about the concepts which I have demonstrated in the four part series. Part 1 | Part 2 | Part 3 | Part 4 Seek Predicate is the operation that describes the b-tree portion of the Seek. Predicate is the operation that describes the additional filter using non-key columns. Based on the description, it is very clear that Seek Predicate is better than Predicate as it searches indexes whereas in Predicate, the search is on non-key columns – which implies that the search is on the data in page files itself. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL Server – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administration assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. 2010 Recycle Error Log – Create New Log file without Server Restart Once I observed a DBA to restaring the SQL Server when he needed new error log file. This was funny and sad both at the same time. There is no need to restart the server to create a new log file or recycle the log file. You can run sp_cycle_errorlog and achieve the same result. Get Database Backup History for a Single Database Simple but effective script! Reducing CXPACKET Wait Stats for High Transactional Database The subject is very complex and I have done my best to simplify the concept. In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Information Related to DATETIME and DATETIME2 There are quite a lot of confusion with DATETIME and DATETIME2. DATETIME2 is also one of the underutilized datatype of SQL Server.  In this blog post I have written a follow up of the my earlier datetime series where I clarify a few of the concepts related to datetime. Difference Between GETDATE and SYSDATETIME Difference Between DATETIME and DATETIME2 – WITH GETDATE Difference Between DATETIME and DATETIME2 2011 Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” Puzzle – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY You can see that row number 2, 3, 4, and 5 has same SalesOrderID = 43667. The FIRST_VALUE is 78 and LAST_VALUE is 77. Now if these function was working on maximum and minimum value they should have given answer as 77 and 80 respectively instead of 78 and 77. Also the value of FIRST_VALUE is greater than LAST_VALUE 77. Why? Explain in detail. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available Our book was out of stock in 48 hours of it was arrived in stock! We got call from the online store with a request for more copies within 12 hours. But we had printed only as many as we had sent them. There were no extra copies. We finally talked to the printer to get more copies. However, due to festivals and holidays the copies could not be shipped to the online retailer for two days. We knew for sure that they were going to be out of the book for 48 hours. This is the story of how we overcame that situation! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Allocating memory inside a function and returning it back

  - by user2651062

  I want to pass a pointer to my function and allocate the memory to which this pointer points. I've read in other posts that I should pass a double pointer to this function and I did so, but I keep getting segmentation fault: #include <iostream> #include <stdlib.h> using namespace std; void allocate(unsigned char** t) { *t=(unsigned char*)malloc(3*sizeof(unsigned char)); if(*t == NULL) cout<<"Allcoation failed"<<endl; else for(int m=0;m<3;m++) *(t[m])=0; } int main() { unsigned char* t; allocate(&t); cout<<t[0]<<" "<<t[1]<<endl; return 0; } the result is always this: Segmentation fault (core dumped) I don't think that there's anything missing from this code. What could be wrong?

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• Free memory outside function [migrated]

  - by Dev Bag

  Can you please help with this issue, is the below gonna leak memory or is it ok? and please let me know if there is something else that I need to pay attention to typedef struct { int len; UC * message; }pack; pack * prepare_packet_to_send(const int length,const unsigned char tag,const int numargs, ... ) { pack *layer= malloc(sizeof(pack)); va_list listp; va_start( listp, numargs ); int step = 0; layer->message = (unsigned char *) malloc(length); layer->len = length; int i = 0; int len = 0; unsigned char *source_message ; for( i = 0 ; i < numargs; i++ ) { source_message = va_arg( listp, unsigned char *); len = va_arg( listp, long); memcpy(layer->message+step, source_message, (long) len); step+=len; } va_end( listp ); return layer; } main() { pack *test = call prepare_packet_to_send(sizeof(var1)+sizeof(var2),any tag,any args) // are following two frees correct/enough? or is there something else i need to do to prevent mem leak? free(test->message); free(test); }

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• Java Animation Memory Overload [on hold]

  - by user2425429

  I need a way to reduce the memory usage of these programs while keeping the functionality. Every time I add 50 milliseconds or so to the set&display loop in AnimationTest1, it throws an out of memory error. Here is the code I have now: import java.awt.DisplayMode; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Polygon; import java.util.ArrayList; import java.util.List; import java.util.concurrent.Executor; import java.util.concurrent.Executors; import javax.swing.ImageIcon; public class AnimationTest1 { public static void main(String args[]) { AnimationTest1 test = new AnimationTest1(); test.run(); } private static final DisplayMode POSSIBLE_MODES[] = { new DisplayMode(800, 600, 32, 0), new DisplayMode(800, 600, 24, 0), new DisplayMode(800, 600, 16, 0), new DisplayMode(640, 480, 32, 0), new DisplayMode(640, 480, 24, 0), new DisplayMode(640, 480, 16, 0) }; private static final long DEMO_TIME = 4000; private ScreenManager screen; private Image bgImage; private Animation anim; public void loadImages() { // create animation List<Polygon> polygons=new ArrayList(); int[] x=new int[]{20,4,4,20,40,56,56,40}; int[] y=new int[]{20,32,40,44,44,40,32,20}; polygons.add(new Polygon(x,y,8)); anim = new Animation(); //# of frames long startTime = System.currentTimeMillis(); long currTimer = startTime; long elapsedTime = 0; boolean animated = false; Graphics2D g = screen.getGraphics(); int width=200; int height=200; //set&display loop while (currTimer - startTime < DEMO_TIME*2) { //draw the polygons if(!animated){ for(int j=0; j<polygons.size();j++){ for(int pos=0; pos<polygons.get(j).npoints; pos++){ polygons.get(j).xpoints[pos]+=1; } } anim.setNewPolyFrame(polygons , width , height , 64); } else{ // update animation anim.update(elapsedTime); draw(g); g.dispose(); screen.update(); try{ Thread.sleep(20); } catch(InterruptedException ie){} } if(currTimer - startTime == DEMO_TIME) animated=true; elapsedTime = System.currentTimeMillis() - currTimer; currTimer += elapsedTime; } } public void run() { screen = new ScreenManager(); try { DisplayMode displayMode = screen.findFirstCompatibleMode(POSSIBLE_MODES); screen.setFullScreen(displayMode); loadImages(); } finally { screen.restoreScreen(); } } public void draw(Graphics g) { // draw background g.drawImage(bgImage, 0, 0, null); // draw image g.drawImage(anim.getImage(), 0, 0, null); } } ScreenManager: import java.awt.Color; import java.awt.DisplayMode; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Toolkit; import java.awt.Window; import java.awt.event.KeyListener; import java.awt.event.MouseListener; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import javax.swing.JFrame; import javax.swing.JPanel; public class ScreenManager extends JPanel { private GraphicsDevice device; /** Creates a new ScreenManager object. */ public ScreenManager() { GraphicsEnvironment environment=GraphicsEnvironment.getLocalGraphicsEnvironment(); device = environment.getDefaultScreenDevice(); setBackground(Color.white); } /** Returns a list of compatible display modes for the default device on the system. */ public DisplayMode[] getCompatibleDisplayModes() { return device.getDisplayModes(); } /** Returns the first compatible mode in a list of modes. Returns null if no modes are compatible. */ public DisplayMode findFirstCompatibleMode( DisplayMode modes[]) { DisplayMode goodModes[] = device.getDisplayModes(); for (int i = 0; i < modes.length; i++) { for (int j = 0; j < goodModes.length; j++) { if (displayModesMatch(modes[i], goodModes[j])) { return modes[i]; } } } return null; } /** Returns the current display mode. */ public DisplayMode getCurrentDisplayMode() { return device.getDisplayMode(); } /** Determines if two display modes "match". Two display modes match if they have the same resolution, bit depth, and refresh rate. The bit depth is ignored if one of the modes has a bit depth of DisplayMode.BIT_DEPTH_MULTI. Likewise, the refresh rate is ignored if one of the modes has a refresh rate of DisplayMode.REFRESH_RATE_UNKNOWN. */ public boolean displayModesMatch(DisplayMode mode1, DisplayMode mode2) { if (mode1.getWidth() != mode2.getWidth() || mode1.getHeight() != mode2.getHeight()) { return false; } if (mode1.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && mode2.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && mode1.getBitDepth() != mode2.getBitDepth()) { return false; } if (mode1.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && mode2.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && mode1.getRefreshRate() != mode2.getRefreshRate()) { return false; } return true; } /** Enters full screen mode and changes the display mode. If the specified display mode is null or not compatible with this device, or if the display mode cannot be changed on this system, the current display mode is used. <p> The display uses a BufferStrategy with 2 buffers. */ public void setFullScreen(DisplayMode displayMode) { JFrame frame = new JFrame(); frame.setUndecorated(true); frame.setIgnoreRepaint(true); frame.setResizable(true); device.setFullScreenWindow(frame); if (displayMode != null && device.isDisplayChangeSupported()) { try { device.setDisplayMode(displayMode); } catch (IllegalArgumentException ex) { } } frame.createBufferStrategy(2); Graphics g=frame.getGraphics(); g.setColor(Color.white); g.drawRect(0, 0, frame.WIDTH, frame.HEIGHT); frame.paintAll(g); g.setColor(Color.black); g.dispose(); } /** Gets the graphics context for the display. The ScreenManager uses double buffering, so applications must call update() to show any graphics drawn. <p> The application must dispose of the graphics object. */ public Graphics2D getGraphics() { Window window = device.getFullScreenWindow(); if (window != null) { BufferStrategy strategy = window.getBufferStrategy(); return (Graphics2D)strategy.getDrawGraphics(); } else { return null; } } /** Updates the display. */ public void update() { Window window = device.getFullScreenWindow(); if (window != null) { BufferStrategy strategy = window.getBufferStrategy(); if (!strategy.contentsLost()) { strategy.show(); } } // Sync the display on some systems. // (on Linux, this fixes event queue problems) Toolkit.getDefaultToolkit().sync(); } /** Returns the window currently used in full screen mode. Returns null if the device is not in full screen mode. */ public Window getFullScreenWindow() { return device.getFullScreenWindow(); } /** Returns the width of the window currently used in full screen mode. Returns 0 if the device is not in full screen mode. */ public int getWidth() { Window window = device.getFullScreenWindow(); if (window != null) { return window.getWidth(); } else { return 0; } } /** Returns the height of the window currently used in full screen mode. Returns 0 if the device is not in full screen mode. */ public int getHeight() { Window window = device.getFullScreenWindow(); if (window != null) { return window.getHeight(); } else { return 0; } } /** Restores the screen's display mode. */ public void restoreScreen() { Window window = device.getFullScreenWindow(); if (window != null) { window.dispose(); } device.setFullScreenWindow(null); } /** Creates an image compatible with the current display. */ public BufferedImage createCompatibleImage(int w, int h, int transparency) { Window window = device.getFullScreenWindow(); if (window != null) { GraphicsConfiguration gc = window.getGraphicsConfiguration(); return gc.createCompatibleImage(w, h, transparency); } return null; } } Animation: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Polygon; import java.awt.image.BufferedImage; import java.util.ArrayList; import java.util.List; /** The Animation class manages a series of images (frames) and the amount of time to display each frame. */ public class Animation { private ArrayList frames; private int currFrameIndex; private long animTime; private long totalDuration; /** Creates a new, empty Animation. */ public Animation() { frames = new ArrayList(); totalDuration = 0; start(); } /** Adds an image to the animation with the specified duration (time to display the image). */ public synchronized void addFrame(BufferedImage image, long duration){ ScreenManager s = new ScreenManager(); totalDuration += duration; frames.add(new AnimFrame(image, totalDuration)); } /** Starts the animation over from the beginning. */ public synchronized void start() { animTime = 0; currFrameIndex = 0; } /** Updates the animation's current image (frame), if necessary. */ public synchronized void update(long elapsedTime) { if (frames.size() >= 1) { animTime += elapsedTime; /*if (animTime >= totalDuration) { animTime = animTime % totalDuration; currFrameIndex = 0; }*/ while (animTime > getFrame(0).endTime) { frames.remove(0); } } } /** Gets the Animation's current image. Returns null if this animation has no images. */ public synchronized Image getImage() { if (frames.size() > 0&&!(currFrameIndex>=frames.size())) { return getFrame(currFrameIndex).image; } else{ System.out.println("There are no frames!"); System.exit(0); } return null; } private AnimFrame getFrame(int i) { return (AnimFrame)frames.get(i); } private class AnimFrame { Image image; long endTime; public AnimFrame(Image image, long endTime) { this.image = image; this.endTime = endTime; } } public void setNewPolyFrame(List<Polygon> polys,int imagewidth,int imageheight,int time){ BufferedImage image=new BufferedImage(imagewidth, imageheight, 1); Graphics g=image.getGraphics(); for(int i=0;i<polys.size();i++){ g.drawPolygon(polys.get(i)); } addFrame(image,time); g.dispose(); } }

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• Lack of Virtual Memory - confusion

  - by Wesley

  Specs ahead of time: AMD Athlon XP 2400+ @ 2.00 GHz / 1 GB PC-3200 DDR RAM / 160 GB IDE HDD / 128 MB GeForce 6200 AGP / FIC AM37 / 350W PSU / Windows XP Pro SP3 So, XP has pop-ups saying that I am low on virtual memory. However, I have a program called SmartRAM (part of Advanced SystemCare by IObit) and it displays CPU & Page File Usage and Free Physical and Virtual Memory. That program shows that I have at least 2000 MB free virtual memory on my machine when the XP pop-ups say that I'm low on virtual memory. First off, would a complete lack of virtual memory cause my computer to freeze? Secondly, how can I solve this lack of virtual memory? (A complete reformat is possible but can't be done immediately...) Thanks in advance.

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• Windows 7 using exactly HALF the installed memory

  - by Nathan Ridley

  I've taken this directly from system information: Installed Physical Memory (RAM) 4.00 GB Total Physical Memory 2.00 GB Available Physical Memory 434 MB Total Virtual Memory 5.10 GB Available Virtual Memory 1.19 GB Page File Space 3.11 GB Also the BIOS reports a full 4GB available. Note the 4gb installed, yet 2gb total. I understand that on a 32 bit operating system, you'll never get the full 4gb of ram, however typically you'll get in the range of 2.5-3.2gb of ram. I have only 2gb available! My swap file goes nuts when I do anything! Note that I have dual SLI nvidia video cards, each with 512mb of on board ram, though I have the SLI feature turned off. Anybody know why Windows might claim that I have exactly 2gb of ram total? Note: previously asked on SuperUser, but closed as "belongs on superuser" before this site opened: http://serverfault.com/questions/39603/windows-7-using-exactly-half-the-installed-memory (I still need an answer!)

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• High Memory Utilization on weblogic

  - by Anup

  My Weblogic App Server shows high Memory Utization. The application seems to perform good without any memeory issues. Now that my traffix is going to increase i am worried about the memory and have a feeling things could go bad and need to take action now and i am confused as to should i increase The JVM memory on the weblogic instances which means adding more physical memory or should i increase the number of managed instances in the cluster. Would like to understand what does having high memory utilization mean and the advantage and disadvantages of adding JVM memory and adding managed instances. Thanks

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• High Memory Utilization on weblogic

  - by Anup

  My Weblogic App Server shows high Memory Utization. The application seems to perform good without any memeory issues. Now that my traffix is going to increase i am worried about the memory and have a feeling things could go bad and need to take action now and i am confused as to should i increase The JVM memory on the weblogic instances which means adding more physical memory or should i increase the number of managed instances in the cluster. Would like to understand what does having high memory utilization mean and the advantage and disadvantages of adding JVM memory and adding managed instances. Thanks

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• Optimal Memory Configuration for Dell PowerEdge 1800 (Windows Server 2000 32bit)

  - by David Murdoch

  I am upgrading the memory on a Dell PowerEdge 1800 Server running Windows Server 2000 (32 bit). My Computer Properties currently reports "2,096,432 KB RAM" (4 modules @ 512MB each). Crucial.com scan reports: "Each memory slot can hold DDR2 PC2-5300 with a maximum of 2GB per slot. Maximum Memory Capacity:  12288MB Currently Installed Memory:  2GB Available Memory Slots:  2 Total Memory Slots:  6 Dual Channel Support:   No CPU Manufacturer:  GenuineIntel CPU Family:  Intel(R) Xeon(TM) CPU 2.80GHz Model 4, Stepping 1 CPU Speed:  2793 MHz Installed in pairs of modules." We will be completely replacing the old 512 MB modules. Will there be any performance difference between installing 4 modules @ 1GB vs. 2 modules @ 2GB?

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• Xinetd , vncserver memory requirement

  - by JP19

  Hi, I am installing the following on a low memory system: vnc4server xinetd xterm openbox obconf I will only occasionally be logging into the vncs for some admin work. My question is: 1) Does xinetd take memory / cpu even when vncserver is not running? If so, can I "run" xinetd on demand (how)? And if no, any idea how much memory it will take when vncserver is not running? 2) Does vncserver take substantial memory when no clients are connected? 3) Do openbox/obconf take memory when vncserver is running but no client are connected? 4) Do openbox/obconf take memory when no vncserver is running? thanks JP

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• SharePoint / SQL Server "out of memory" error

  - by aardvark

  After months of preparation, we launched a new SharePoint intranet portal today. Immediately, some users began getting a "server out of memory" error when they tried to log in. The SharePoint server appeared to be fine, but the SQL Server was reporting 100% memory use. (It has 4 GB.) We rebooted the server and have not had further memory problems, though memory usage is hovering around 60% or above. I'm not convinced that we have solved the problem; I suspect it may return Monday morning when the whole staff tries to log in again. I'm not a database guy, and I'm stumped about how to troubleshoot this. Do we need more memory, or is there somewhere I should look to reduce memory usage?

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• Strategies for memory profiling

  In this whitepaper, Red Gate discusses the importance of handling two common issues in memory management: memory leaks and excessive memory usage. Red Gate demonstrates how their ANTS Memory Profiler can identify issues with memory management and provide a detailed view of a program's memory usage. This whitepaper doubles as a brief tutorial for using the ANTS Memory Profiler by providing an example of a program that is experiencing memory management issues.

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• Vmstat indicates memory is disappearing

  - by jimbotron

  I wanted to profile the memory usage of a script. Here's the output before it was running: procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 15624 186660 39460 439052 0 0 0 2 1 1 0 0 100 0 Here's the output while the script is running, at the point where free memory was at its lowest value: procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu---- r b swpd free buff cache si so bi bo in cs us sy id wa 0 0 15624 11464 40312 473524 0 0 0 2 1 1 0 0 100 0 So free memory dropped by about 175 MB, and I expected that buff would increase by that amount. But it seems the other columns changed by relatively negligible amounts - how is this possible? Am I interpreting this wrong, or is some memory just not being accounted for in this output?

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• Motherboard memory question

  - by JERiv

  I am currently drawing up specs on a new workstation for my office. I am considering the Asus P6X58D for a motherboard. This board's specs list it as supporting 24 gigs of memory. Suppose I were to use six four gig memory cards and then two video cards with 1 gig of memory apiece. Is the maximum supported memory similar to how 32 bit operating systems only have enough address space for 4 gigs of memory? Simply: Will the board post? If so, will the system be able to address all the memory, both the 24 gigs on the ddr3 bus and the 3 gigs on the graphics card?

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• Low CPU/Memory/Memory-bandwith Pathfinding (maybe like in Warcraft 1)

  - by Valmond

  Dijkstra and A* are all nice and popular but what kind of algorithm was used in Warcraft 1 for pathfinding? I remember that the enemy could get trapped in bowl-like caverns which means there were (most probably) no full-path calculations from "start to end". If I recall correctly, the algorithm could be something like this: A) Move towards enemy until success or hitting a wall B) If blocked by a wall, follow the wall until you can move towards the enemy without being blocked and then do A) But I'd like to know, if someone knows :-) [edit] As explained to Byte56, I'm searching for a low cpu/mem/mem-bandwidth algo and wanted to know if Warcraft had some special secrets to deliver (never seen that kind of pathfinding elsewhere), I hope that that is more concordant with the stackexchange rules.

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• If my application doesn't use a lot of memory, can I ignore viewDidUnload:?

  - by iPhoneToucher

  My iPhone app generally uses under 5MB of living memory and even in the most extreme conditions stays under 8MB. The iPhone 2G has 128MB of RAM and from what I've read an app should only expect to have 20-30MB to use. Given that I never expect to get anywhere near the memory limit, do I need to care about memory warnings and setting objects to nil in viewDidUnload:? The only way I see my app getting memory warnings is if something else on the phone is screwing with the memory, in which case the entire phone would be acting silly. I built my app without ever using viewDidUnload:, so there's more than a hundred classes that I'd need to inspect and add code to if I did need to implement it.

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• Free RAM disappears - Memory leak?

  - by Izzy

  On a fresh started system, free reports about 1.5G used RAM (8G RAM alltogether, Ubuntu 12.04 with lightdm and plasma desktop, one konsole window started). Having the apps running I use, it still consumes not more than 2G. However, having the system running for a couple of days, more and more of my free RAM disappears -- without showing up in the list of used apps: while smem --pie=name reports less than 20% used (and 80% being available), everything else says differently. free -m for example reports on about day 7: total used free shared buffers cached Mem: 7459 7013 446 0 178 997 -/+ buffers/cache: 5836 1623 Swap: 9536 296 9240 (so you can see, it's not the buffers or the cache). Today this finally ended with the system crashing completely: the windows manager being gone, apps "hanging in the air" (frameless) -- and a popup notifying me about "too many open files". Syslog reports: kernel: [856738.020829] VFS: file-max limit 752838 reached So I closed those applications I was able to close, and killed X using Ctrl-Alt-backspace. X tried to come up again after that with failsafeX, but was unable to do so as it could no longer detect its configuration. So I switched to a console using Ctrl-Alt-F2, captured all information I could think of (vmstat, free, smem, proc/meminfo, lsof, ps aux), and finally rebooted. X again came up with failsafeX; this time I told it to "recover from my backed-up configuration", then switched to a console and successfully used startx to bring up the graphical environment. I have no real clue to what is causing this issue -- though it must have to do either with X itself, or with some user processes running on X -- as after killing X, free -m output looked like this: total used free shared buffers cached Mem: 7459 2677 4781 0 62 419 -/+ buffers/cache: 2195 5263 Swap: 9536 59 9477 (~3.5GB being freed) -- to compare with the output after a fresh start: total used free shared buffers cached Mem: 7459 1483 5975 0 63 730 -/+ buffers/cache: 689 6769 Swap: 9536 0 9536 Two more helpful outputs are provided by memstat -u. Shortly before the crash: User Count Swap USS PSS RSS mail 1 0 200 207 616 whoopsie 1 764 740 817 2300 colord 1 3200 836 894 2156 root 62 70404 352996 382260 569920 izzy 80 177508 1465416 1519266 1851840 After having X killed: User Count Swap USS PSS RSS mail 1 0 184 188 356 izzy 1 1400 708 739 1080 whoopsie 1 848 668 826 1772 colord 1 3204 804 888 1728 root 62 54876 131708 149950 267860 And after a restart, back in X: User Count Swap USS PSS RSS mail 1 0 212 217 628 whoopsie 1 0 1536 1880 5096 colord 1 0 3740 4217 7936 root 54 0 148668 180911 345132 izzy 47 0 370928 437562 915056 Edit: Just added two graphs from my monitoring system. Interesting to see: everytime when there's a "jump" in memory consumption, CPU peaks as well. Just found this right now -- and it reminds me of another indicator pointing to X itself: Often when returning to my machine and unlocking the screen, I found something doing heavvy work on my CPU. Checking with top, it always turned out to be /usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch -background none. So after this long explanation, finally my questions: What could be the possible causes? How can I better identify involved processes/applications? What steps could be taken to avoid this behaviour -- short from rebooting the machine all X days? I was running 8.04 (Hardy) for about 5 years on my old machine, never having experienced the like (always more than 100 days uptime, before rebooting for e.g. kernel updates). This now is a complete new machine with a fresh install of 8.04. In case it matters, some specs: AMD A4-3400 APU with Radeon(tm) HD Graphics, using the open-source ati/radeon driver (so no fglrx installed), 8GB RAM, WDC WD1002FAEX-0 hdd (1TB), Asus F1A75-V Evo mainboard. Ubuntu 12.04 64-bit with KDE4/Plasma. Apps usually open more or less permanently include Evolution, Firefox, konsole (with Midnight Commander running inside, about 4 tabs), and LibreOffice -- plus occasionally Calibre, Gimp and Moneyplex (banking software I'm already using for almost 20 years now, in a version which did fine on Hardy).

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• Force full garbage collection when memory occupation goes beyond a certain threshold

  - by Silvio Donnini

  I have a server application that, in rare occasions, can allocate large chunks of memory. It's not a memory leak, as these chunks can be claimed back by the garbage collector by executing a full garbage collection. Normal garbage collection frees amounts of memory that are too small: it is not adequate in this context. The garbage collector executes these full GCs when it deems appropriate, namely when the memory footprint of the application nears the allotted maximum specified with -Xmx. That would be ok, if it wasn't for the fact that these problematic memory allocations come in bursts, and can cause OutOfMemoryErrors due to the fact that the jvm is not able to perform a GC quickly enough to free the required memory. If I manually call System.gc() beforehand, I can prevent this situation. Anyway, I'd prefer not having to monitor my jvm's memory allocation myself (or insert memory management into my application's logic); it would be nice if there was a way to run the virtual machine with a memory threshold, over which full GCs would be executed automatically, in order to release very early the memory I'm going to need. Long story short: I need a way (a command line option?) to configure the jvm in order to release early a good amount of memory (i.e. perform a full GC) when memory occupation reaches a certain threshold, I don't care if this slows my application down every once in a while. All I've found till now are ways to modify the size of the generations, but that's not what I need (at least not directly). I'd appreciate your suggestions, Silvio P.S. I'm working on a way to avoid large allocations, but it could require a long time and meanwhile my app needs a little stability

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• shredding a memory card???

  - by bala3569

  Hi, I want to shred my memory card and i dont want to recover any files from that memory card...Is it possible??If so den which tool(best shredding tool) is best?

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• How much memory should my rails stack be consuming?

  - by Hamish

  I am running my own webserver on a 384MB VPS from Slicehost to serve two Ruby on Rails applications on separate Virtual Hosts. I am running Phusion Passenger with Apache2. The following is the contents of my Passenger.conf <IfModule passenger_module> PassengerRoot /opt/ruby-enterprise-1.8.6-20090610/lib/ruby/gems/1.8/gems/passenger-2.2.11 PassengerLogLevel 0 PassengerRuby /usr/local/bin/ruby PassengerUserSwitching on PassengerDefaultUser nobody PassengerMaxPoolSize 3 PassengerMaxInstancesPerApp 2 PassengerPoolIdleTime 300 # Ruby on Rails Options RailsAutoDetect on RailsSpawnMethod smart NameVirtualHost *:80 If i do a 'top' on my server I have 314MB used on average, this seems like too much? Am I mistaken and if not what possible steps can I take to reduce the Memory usage? Thanks!

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• free -m output, should I be concerend about this servers low memory?

  - by Michael

  This is the output of free -m on a production database (MySQL with machine. 83MB looks pretty bad, but I assume the buffer/cache will be used instead of Swap? [admin@db1 www]$ free -m total used free shared buffers cached Mem: 16053 15970 83 0 122 5343 -/+ buffers/cache: 10504 5549 Swap: 2047 0 2047 top ouptut sorted by memory: top - 10:51:35 up 140 days, 7:58, 1 user, load average: 2.01, 1.47, 1.23 Tasks: 129 total, 1 running, 128 sleeping, 0 stopped, 0 zombie Cpu(s): 6.5%us, 1.2%sy, 0.0%ni, 60.2%id, 31.5%wa, 0.2%hi, 0.5%si, 0.0%st Mem: 16439060k total, 16353940k used, 85120k free, 122056k buffers Swap: 2096472k total, 104k used, 2096368k free, 5461160k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 20757 mysql 15 0 10.2g 9.7g 5440 S 29.0 61.6 28588:24 mysqld 16610 root 15 0 184m 18m 4340 S 0.0 0.1 0:32.89 sysshepd 9394 root 15 0 154m 8336 4244 S 0.0 0.1 0:12.20 snmpd 17481 ntp 15 0 23416 5044 3916 S 0.0 0.0 0:02.32 ntpd 2000 root 5 -10 12652 4464 3184 S 0.0 0.0 0:00.00 iscsid 8768 root 15 0 90164 3376 2644 S 0.0 0.0 0:00.01 sshd

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• iPhone development: pointer being freed was not allocated

  - by w4nderlust

  Hello, i got this message from the debugger: Pixture(1257,0xa0610500) malloc: *** error for object 0x21a8000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug so i did a bit of tracing and got: (gdb) shell malloc_history 1257 0x21a8000 ALLOC 0x2196a00-0x21a89ff [size=73728]: thread_a0610500 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopDoObservers | CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) | CA::Transaction::commit() | CA::Context::commit_transaction(CA::Transaction*) | CALayerDisplayIfNeeded | -[CALayer _display] | CABackingStoreUpdate | backing_callback(CGContext*, void*) | -[CALayer drawInContext:] | -[UIView(CALayerDelegate) drawLayer:inContext:] | -[AvatarView drawRect:] | -[AvatarView overlayPNG:] | +[UIImageUtility createMaskOf:] | UIGraphicsGetImageFromCurrentImageContext | CGBitmapContextCreateImage | create_bitmap_data_provider | malloc | malloc_zone_malloc and i really can't understand what i am doing wrong. here's the code of the [UIImageUtility createMaskOf:] function: + (UIImage *)createMaskOf:(UIImage *)source { CGRect rect = CGRectMake(0, 0, source.size.width, source.size.height); UIGraphicsBeginImageContext(CGSizeMake(source.size.width, source.size.height)); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(context, 0, source.size.height); CGContextScaleCTM(context, 1.0, -1.0); UIImage *original = [self createGrayCopy:source]; CGContextRef context2 = CGBitmapContextCreate(NULL, source.size.width, source.size.height, 8, 4 * source.size.width, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipLast); CGContextDrawImage(context2, CGRectMake(0, 0, source.size.width, source.size.height), original.CGImage); CGImageRef unmasked = CGBitmapContextCreateImage(context2); const float myMaskingColorsFrameColor[6] = { 1,256,1,256,1,256 }; CGImageRef mask = CGImageCreateWithMaskingColors(unmasked, myMaskingColorsFrameColor); CGContextSetRGBFillColor (context, 256,256,256, 1); CGContextFillRect(context, rect); CGContextDrawImage(context, rect, mask); UIImage *whiteMasked = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return whiteMasked; } the other custom function called before that is the following: - (UIImage *)overlayPNG:(SinglePart *)sp { NSLog([sp description]); // Rect and context setup CGRect rect = CGRectMake(0, 0, sp.image.size.width, sp.image.size.height); NSLog(@"%f x %f", sp.image.size.width, sp.image.size.height); // Create an image of a color filled rectangle UIImage *baseColor = nil; if (sp.hasOwnColor) { baseColor = [UIImageUtility imageWithRect:rect ofColor:sp.color]; } else { SinglePart *facePart = [editingAvatar.face.partList objectAtIndex:0]; baseColor = [UIImageUtility imageWithRect:rect ofColor:facePart.color]; } // Crete the mask of the layer UIImage *mask = [UIImageUtility createMaskOf:sp.image]; mask = [UIImageUtility createGrayCopy:mask]; // Create a new context for merging the overlay and a mask of the layer UIGraphicsBeginImageContext(CGSizeMake(sp.image.size.width, sp.image.size.height)); CGContextRef context2 = UIGraphicsGetCurrentContext(); // Adjust the coordinate system so that the origin // is in the lower left corner of the view and the // y axis points up CGContextTranslateCTM(context2, 0, sp.image.size.height); CGContextScaleCTM(context2, 1.0, -1.0); // Create masked overlay color layer CGImageRef MaskedImage = CGImageCreateWithMask (baseColor.CGImage, mask.CGImage); // Draw the base color layer CGContextDrawImage(context2, rect, MaskedImage); // Get the result of the masking UIImage* overlayMasked = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); UIGraphicsBeginImageContext(CGSizeMake(sp.image.size.width, sp.image.size.height)); CGContextRef context = UIGraphicsGetCurrentContext(); // Adjust the coordinate system so that the origin // is in the lower left corner of the view and the // y axis points up CGContextTranslateCTM(context, 0, sp.image.size.height); CGContextScaleCTM(context, 1.0, -1.0); // Get the result of the blending of the masked overlay and the base image CGContextDrawImage(context, rect, overlayMasked.CGImage); // Set the blend mode for the next drawn image CGContextSetBlendMode(context, kCGBlendModeOverlay); // Component image drawn CGContextDrawImage(context, rect, sp.image.CGImage); UIImage* blendedImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); CGImageRelease(MaskedImage); return blendedImage; }

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• Server high memory usage at same time every day

  - by Sam Parmenter

  Right, we moved one of our main sites onto a new AWS box with plenty of grunt as it would allow us more control that we had before and future proof ourselves. About a month ago we started running into issues with high memory usage at the same time every day. In the morning an export is run to export data to a file which is the FTPed to a local machine for processing. The issues were co-inciding with the rough time of the export but when we didn't run the export one day, the server still ran into the same issues. The export has been run at other times in the day since to monitor memory usage to see if it spikes. The conclusion is that the export is fine and barely touches the sides memory wise. No noticeable change in memory usage. When the issue happens, its effect is to kill mysql and require us to restart the process. We think it might be a mysql memory issue, but might just be that mysql is just the first to feel it. Looking at the logs there is no particular query run before the memory usage hits 90%. When it strikes at about 9:20am, the memory usage spikes from a near constant 25% to 98% and very quickly kills mysql to save itself. It usually takes about 3-4 minutes to die. There are no cron jobs running at that time of the day and we haven't noticed a spike in traffic over the period of the issues. Any help would be massively appreciated! thanks.

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