Search Results

Search found 40567 results on 1623 pages for 'database performance'.

Page 183/1623 | < Previous Page | 179 180 181 182 183 184 185 186 187 188 189 190  | Next Page >

• Is it convenient to use a XML/JSON generated based system? [closed]

  - by Marcelo de Assis

  One of my clients insists that we missed a requisite for the project(a little social network, using PHP + MySql), is that all queries are made from XML / JSON static files (using AJAX) and not directly from the database. Edit: The main reason, stated by client, is a way to economize bandwith. Even the file loading, has to be using AJAX, to avoid server side processing. We will still use a database to store and insert data. These XML / JSON files will be (re) generated whenever any data is changed by CMS or users. As the project was developed without this "technique", we'll have a lot of work ahead, so I would like to avoid that. I'm asking if it's convenient to use a XML generated based system, because I think a database is already "optimized" and secure to deal with a lot of data traffic. Other issue I'm afraid of, is a chance of conflict when a user is trying to read a XML/JSON which is being just generated.

  Read the article

• What is the best way to keep track of the median?

  - by Steven Mou

  I read a question in one book: Numbers are randomly generated and stored into an (expanding) array, How would you keep track of the median? There are two data structures can solve the problem. One is the balanced binary tree, the other is two heaps which keep trace of the biggest half and the smallest half of the elements. I think these two solutions has the same running time as O(n lg n), but I am not sure of my judgement. In your opinions, What is the best way to keep track of the median?

  Read the article

• Regulating how much to draw based on how much was drawn last frame.

  - by Mike Howard

  I have a 3D game world on an iPhone (limited graphics speed), and I'm already regulating whether I draw each shape on the screen based on it's size and distance from the camera. Something like... if (how_big_it_looks_from_the_camera > constant) then draw What I want to do now is also take into account how many shapes are being drawn, so that in busier areas of the game world I can draw less than I otherwise would. I tried to do this by dividing how_big_it_looks by the number of shapes that were drawn last frame (well, the square root of this but I'm simplifying - the problem is the same). if (how_big_it_looks / shapes_drawn > constant2) then draw But the check happens at the level of objects which represent many drawn shapes, and if an object containing many shapes is switched on, it increases shapes_drawn lots and switches itself back off the next frame. It flickers on and off. I tried keeping a kind of weighted average of previous values, by each frame doing something like shapes_drawn_recently = 0.9 * shapes_drawn_recently + 0.1 * shapes_just_drawn, but of course it only slows the flickering down because of the nature of the feedback loop. Is there a good way of solving this? My project is in Objective-C, but a general algorithm or pseudo-code is good too. Thanks.

  Read the article

• Demantra Partitioning and the First PK Column

  - by user702295

    We have found that it is necessary in Demantra to have an index that matches the partition key, although it does not have to be the PK.  It is ok   to create a new index instead of changing the PK.   For example, if my PK on SALES_DATA is (ITEM_ID, LOCATION_ID, SALES_DATE) and I decide partition by SALES_DATE, then I should add an index starting   with the partition key like this: (SALES_DATE, ITEM_ID, LOCATION_ID).   * Note that the first column of the new index matches the partition key.   It might also be helpful to create a 2nd index with the other PK columns reversed (SALES_DATE, LOCATION_ID, ITEM_ID). Again, the first column   matches the partition key.

  Read the article

• Designing a flexible tile-based engine

  - by Vee

  I'm trying to create a flexible tile-based game engine to make all sorts of non-realtime puzzle games, just as Bejeweled, Civilization, Sokoban, and so on. The first approach I had was to have a 2D array of Tile objects, and then have classes inheriting from Tile that represented the game objects. Unfortunately that way I couldn't stack more game elements on the same Tile without having a 3D array. Then I did something different: I still had the 2D array of Tile objects, but every Tile object contained a List where I put and different entities. This worked fine until 20 minutes ago, when I realized that it's too expensive to do many things, look at this example: I have a Wall entity. Every update I have to check the 8 adjacent Tiles, then check all of the entities in the Tile's List, check if any of those entities is a Wall, then finally draw the correct sprite. (This is done to draw walls that are next to each other seamlessly) The only solution I see now is having a 3D array, with many layers, that could suit every situation. But that way I can't stack two entities that share the same layer on the same tile. Whenever I want to do that I have to create a new layer. Is there a better solution? What would you do?

  Read the article

• Cat 6 Only 100mbit speed

  - by Stu2000

  I tried two different cat6 cables directly connected between my two ubuntu machines. This one I ordered online: http://www.amazon.co.uk/gp/product/B002SQPDXS/ref=wms_ohs_product only achieves 100mbit speeds, but does appear to be supporting cross-talk (direct pc to pc), the other cat 6 cable, worked perfectly and gets the full 1gigabit speed. Both tests were performed using ftp and checking the network monitor with direct pc to pc connection. Did the product from amazon lie to me or do I need to manually set a setting somewhere in ubuntu for some cables? I had thought 10 quid for 20m of gigabit ethernet cable was a bit cheap, you get what you pay for... Regards, Stu Update: It seems that after rebooting, the device is set to 1000mbit sec when looking it up with sudo ethtool eth0 However after a while, this will drop down to just 100, after which to reset it to 1000 again, I have to reboot, and simply unpugging and re-plugging in the cable doesn't do it. I tried setting this in networking config file as suggested here: auto eth0 iface eth0 inet static pre-up /usr/sbin/ethtool -s eth0 speed 1000 duplex full but that resulted in my networking failing to start. Is there a problem with my 'auto-negotiation' or something? Can I manually override a setting to 1000mbit?

  Read the article

• Current trends in Random Access Memory

  - by Nutel

  As I know for now because of laws of Physics there will be not any tangible improvements in CPU cycles per second for the nearest future. However because of Von Neumann bottleneck it seems to not be an issue for non-server applications. So what about RAM, is there any upcoming technologies that promise to improve memory speed or we are stack with the current situation till quantum computers will come out from labs?

  Read the article

• Why after each restart, my local .NET sites take time to load for the first time?

  - by Saeed Neamati

  I'm developing sites based on .NET platform. I usually deploy these sites on my local IIS, so that I can test them and see their functionality before going live. However, each time I restart windows, it seems that sites take a long time to run for the first time. I know about JIT and I'm also aware of this question, but it doesn't answer my question. Does JIT happens every time you restart windows? Is it related to creation of w3wp.exe process? Why sites are so slow for the first request after each restart?

  Read the article

• Java Spotlight Episode 98: Cliff Click on Benchmarkings

  - by Roger Brinkley

  Interview with Cliff Click of 0xdata on benchmarking. Recorded live at JFokus 2012. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link:  Java Spotlight Podcast in iTunes. Show Notes News Bean Validation 1.1 Java EE 7 Roadmap Java JRE Update 7u7 and 6u35 available. Change to Java SE 7 and Java SE 6 Update Release Numbers JCP 2012 Award Nominations Announced Griffon JavaFX Plugin Events Sep 3-6, Herbstcampus, Nuremberg, Germany Sep 10-15, IMTS 2012 Conference,  Chicago Sep 12,  The Coming M2M Revolution: Critical Issues for End-to-End Software and Systems Development,  Webinar Sep 30-Oct 4, JavaONE, San Francisco Oct 3-4, Java Embedded @ JavaONE, San Francisco Oct 15-17, JAX London Oct 30-Nov 1, Arm TechCon, Santa Clara Oct 22-23, Freescale Technology Forum - Japan, Tokyo Nov 2-3, JMagreb, Morocco Nov 13-17, Devoxx, Belgium Feature Interview Cliff Click is the CTO and Co-Founder of 0xdata, a firm dedicated to creating a new way to think about web-scale data storage and real-time analytics. I wrote my first compiler when I was 15 (Pascal to TRS Z-80!), although my most famous compiler is the HotSpot Server Compiler (the Sea of Nodes IR). I helped Azul Systems build an 864 core pure-Java mainframe that keeps GC pauses on 500Gb heaps to under 10ms, and worked on all aspects of that JVM. Before that I worked on HotSpot at Sun Microsystems, and am at least partially responsible for bringing Java into the mainstream. I am invited to speak regularly at industry and academic conferences and has published many papers about HotSpot technology. I hold a PhD in Computer Science from Rice University and about 15 patents. What’s Cool Shaun Smith’s Devoxx 2011 talk "JPA Multi-Tenancy & Extensibility" now freely available at Parleys.

  Read the article

• Add-ons for Firefox - Java Plugin has been blocked JRE versions below 1.6.0_31 or between 1.7.0 and 1.7.0_2

  - by user702295

  As Java 1.6u31 is not certified for use with EBS or Demantra, you may notice issues in relation to the Java plug-in.  Demantra Development is currently working to certify Java 1.6u31.  They are recommending that you upgrade to that version. EBS customers, should not be installing 1.6u31 as it is not certified.  If you do upgrade your browser, you will either need to downgrade to a lower release of Firefox or find a way of allowing Firefox to use the older version of the Java Plug-in.

  Read the article

• OpenGL profiling with AMD PerfStudio 2

  - by Aurus

  I'm rendering just a really small amount of polygons for my UI but however I still tried to increase the FPS. In the end I removed redundant calls which increased the FPS. I really don't want to lose FPS for nothing so I keep looking for more improvements. The first thing I noticed is the "huge" time where no calls are made before SwapBuffer (the black one). Well I know that OpenGL works asynchronous so SwapBuffer has to wait until everything is done. But shouldn't PerfStudio mark this time also as black ? Correct me If I am wrong. The second thing I noticed is that some glUniform2f calls just take longer (the brown ones). I mean they should all upload 2floats to the GPU how can the time be so different from call to call. The program isn't even changed or something like that. I also tried to look at other programs like gDebugger or CodeXL but they often crashed and they show less statistics (only # of calls or redundant calls etc.) EDIT: I also realized that the draw calls also have different durations, which was obvious for me but sometimes drawing more vertices is faster than drawing less vertices.

  Read the article

• How to become a "faster" programmer?

  - by Nick Gotch

  My last job evaluation included just one weak point: timeliness. I'm already aware of some things I can do to improve this but what I'm looking for are some more. Does anyone have tips or advice on what they do to increase the speed of their output without sacrificing its quality? How do you estimate timelines and stick to them? What do you do to get more done in shorter time periods? Any feedback is greatly appreciated, thanks,

  Read the article

• Slides and demo code for Columnstore Index session

  - by Hugo Kornelis

  Almost a week has passed after SQLBits X in London , so I guess it’s about time for me to share the slides and demo code of my session on columnstore indexes. After all, I promised people I would do that – especially when I found out that I had enough demos prepared to fill two sessions! I made some changes to the demo code. I added extra comments, not only to the demos I could not explain and run during the session, but also to the rest, so that people who missed the session will also be able to...(read more)

  Read the article

• Spatial data from shapefiles (for T-SQL Tuesday #006)

  - by Rob Farley

  I’m giving a presentation on May 12th at the Adelaide .Net User Group, around the topic of spatial data, and in particular, the visualization of said data. Given that it’s about one the larger types, this post should also count towards Michael Coles’ T-SQL Tuesday on BLOB data . I wrote recently about my experience with exploded data , but what I didn’t go on to talk about was how using a shapefile like this would translate into a scenario with a much larger number of shapes, such as all the postcode...(read more)

  Read the article

• How to efficiently map tokens to code in a script interpreter?

  - by lithander

  I'm writing an interpreter for a simple scripting language where each line is a complete, executable command. (Like the instructions in assembler) When parsing a line I have to map the requested command to actual code. My current solution looks like this: std::string op, param1, param2; //parse line, identify op, param1, param2 ... //call command specific code if(op == "MOV") ExecuteMov(AsNumber(param1)); else if(op == "ROT") ExecuteRot(AsNumber(param1)); else if(op == "SZE") ExecuteSze(AsNumber(param1)); else if(op == "POS") ExecutePos((AsNumber(param1), AsNumber(param2)); else if(op == "DIR") ExecuteDir((AsNumber(param1), AsNumber(param2)); else if(op == "SET") ExecuteSet(param1, AsNumber(param2)); else if(op == "EVL") ... The more commands are supported the more string comparisions I'll have to do to identify and call the associated method. Can you point me to a more efficient implementation in the described scenario?

  Read the article

• Using JDBC to asynchronously read large Oracle table

  - by Ben George

  What strategies can be used to read every row in a large Oracle table, only once, but as fast as possible with JDBC & Java ? Consider that each row has non-trivial amounts of data (30 columns, including large text in some columns). Some strategies I can think of are: Single thread and read table. (Too slow, but listed for clarity) Read the id's into ConcurrentLinkedQueue, use threads to consume queue and query by id in batches. Read id's into a JMS queue, use workers to consume queue and query by id in batches. What other strategies could be used ? For the purpose of this question assume processing of rows to be free.

  Read the article

• Webscale is all about sharding and its coming to SQL Azure

  - by simonsabin

  There are many that joke about developers always talking about webscale and needing to shard to be able to scale. In reality many systems, if not most, don’t need to be able to scale to numerous nodes because todays processing is so powerful. However in the cloud world where you don’t have 1 big box you have many little ones (instances) you need some way of sharding/federating/distributing data and load. I’ve mentioned before of a PDC presentation on whats coming in SQL Azure, well they’ve put some...(read more)

  Read the article

• What are the Crappy Code Games - Tips on how to win?

  - by simonsabin

  This is part of a series on the Crappy Code Games The background Who can enter? What are the challenges? What are the prizes? Why should I attend? Tips on how to win Tips on how to win Each test has some different aspect that will define how you win. In this post we will give you some tips on how to try and win. As a starter why not watch some of the sessions from previous SQLBits Storage sessions Sessions on IO The background Who can enter? What are the challenges? What are the prizes? Why should...(read more)

  Read the article

• Object pools for efficient resource management

  - by GameDevEnthusiast

  How can I avoid using default new() to create each object? My previous demo had very unpleasant framerate hiccups during dynamic memory allocations (usually, when arrays are resized), and creating lots of small objects which often contain one pointer to some DirectX resource seems like an awful lot of waste. I'm thinking about: Creating a master look-up table to refer to objects by handles (for safety & ease of serialization), much like EntityList in source engine Creating a templated object pool, which will store items contiguously (more cache-friendly, fast iteration, etc.) and the stored elements will be accessed (by external systems) via the global lookup table. The object pool will use the swap-with-last trick for fast removal (it will invoke the object's ~destructor first) and will update the corresponding indices in the global table accordingly (when growing/shrinking/moving elements). The elements will be copied via plain memcpy(). Is it a good idea? Will it be safe to store objects of non-POD types (e.g. pointers, vtable) in such containers? Related post: Dynamic Memory Allocation and Memory Management

  Read the article

• Improving Comparison Operators and Window Functions

  It is dangerous to assume that your data is sound. SQL already has intrinsic ways to cope with missing, or unknown data in its comparison predicate operators, or Theta operators. Can SQL be more effective in the way it deals with data quality? Joe Celko describes how the SQL Standard could soon evolve to deal with data in ways that allow aggregation and windowing in cases where the data quality is less than perfect

  Read the article

• ORA- 01157 / Cant connect to database

  - by Tom

  Hi everyone, this is a follow up from this question. Let me start by saying that i am NOT a DBA, so i'm really really lost with this. A few weeks ago, we lost contact with one of our SID'S. All the other services are working, but this one in particular is not. What we got was this message when trying to connect ORA-01033: ORACLE initialization or shutdown in progress An attempt to alter database open ended up in ORA-01157: cannot identify/lock data file 6 - see DBWR trace file ORA-01110: data file 6: '/u01/app/oracle/oradata/xxx/xxx_data.dbf' I tried to shutdown / restart the database, but got this message. Total System Global Area 566231040 bytes Fixed Size 1220604 bytes Variable Size 117440516 bytes Database Buffers 444596224 bytes Redo Buffers 2973696 bytes Database mounted. ORA-01157: cannot identify/lock data file 6 - see DBWR trace file ORA-01110: data file 6: '/u01/app/oracle/oradata/xxx/xxx_data.dbf' When all continued the same, I erased the dbf files (rm xxx_data.dbf xxx_index.dbf), and recreated them using touch xxx_data.dbf. I also tried to recreate the tablespaces using `CREATE TABLESPACE DATA DATAFILE XXX_DATA.DBF` and got Database not open As I said, i don't know how bad this is, or how far i'm from gaining access to my database (well, to this SID at least, the others are working). I would imagine that a last resource would be to throw everything away, and recreating it, but I don't know how to, and I was hoping there's a less destructive solution. Any help will be greatly appreciated . Thanks in advance.

  Read the article

• Un-used Indexes on MDP_MATRIX Consuming Resources

  - by user702295

  Disable un-used Indexes: As much as it is recommended to create relevant indexes, it is advised not to have too many indexes on the mdp_matrix table.  Too many indexes will cause long waits on the table as indexes needs to get updated every time the table is updated.  There are many seeded indexes on mdp_matrix, every out of the box data model level has an index on the matrix table.  If a level is unused in the specific data model of the implementation, it is advisable to disable that index.  If the customer is not sure if and how indexes are utilized, the DBA can monitor all indexes.  After a few cycles of operation, the DBA should go over that list and see which indexes have not been used.  Consider disabling them. There are scripts on the net to monitor indexes or use the monitoring usage clause in the alter index statement.

  Read the article

• Demantra Implementation Tip Windows and Unix or Linux

  - by user702295

  Hello!  Are you implementing using a third party or consulting resources?   Recently we have seen some cases where customers no longer have a windows installation.  After the initial install and configuration, once the instance has gone live, the windows install is either deleted or most likely no longer with the customer as the same was installed on the implementers' laptop to start with. As a result when support comes back requesting the customer to apply a patch and/or upgrade they do not have a windows installation.  This has started happening after Oracle Demantra gave them the option to configure the engine on Unix.  Workaround: It is advisable that the customer keep their Windows installation intact for further patching and/or upgrade.  It is aslo possible that the implementer had installed Demantra on his Windows box and you do not have access to it any more.  It is possible that with the web and engine on Unix, and the silent installer having downloaded all the executable for Business Modeler, to work on the User's client machine, you may no longer need the windows install. I have not tested the above 

  Read the article

• Designing a completly new database/gui solution for my compnay

  - by user1277304

  I'm no expert when it come to Everything Visual Studio 2010 and utilizing SQL server 2008. I'm sure some of my personal projects I've built for personal use would get laughed off the face of the planet, but SQLCe has been the solution I was looking for those home type of projects. And they work, flawlessly. Now I feel it's time to step up to the big league. I want to develop a complete, unified and module based solution for my compnay that I'm working for. We're still using stuff from the 80s for goodness sake! I use Excel and query the ancient database on my own because I can't stand the GUI. Nothing against people of age, but the IDE our programmers are using is from the stone age, and they use APL of all things with it. I've yet to see a radio buttton control anywhere in the GUI where it would make sense. Anyway, I want to do this right from the ground up. I'm by no means a newbie when it comes to programming in .NET 2010, however, I want the entire solution to be professionaly done. I want version control, test projects, project flow, SQL 2008 integration and all the bells and whistles that come with that. I know for a fact that if we had something like that runnning, not only would development costs and time be slashed four fold, but the possibilities for expansion and performance would sky rocket. (Between the GUI an our DB engine, it can only use ONE CORE! ONE! It's 2012 for goodness sake!) Our buisness is growing and our current ancient solution just can't keep up, and I'd hate to see our buisness go down in flames because our programmer is stuck in the 80's and refuses to use anything current. So I ask you guys, the experts and know-it-alls, where do I start? Are there any gems of good books out there in the haystack of all "This for dummies" type of deals? I already have several people backing me in this endevour, and while it may seem brash to just usurp the current programmers, I'm doing this for the company as a whole. Thank you guys for your time.

  Read the article

• What is the difference between all-static-methods and applying a singleton pattern?

  - by shahensha

  I am making a database to store information about the users of my website (I am using stuts2 and hence Java EE technology). For the database I'll be making a DBManager. Should I apply singleton pattern here or rather make all it's methods static? I will be using this DBManager for basic things like adding, deleting and updating User profiles. Along with it, I'll use for all other querying purposes, for instance to find out whether a username already exists and to get all users for administrative purposes and stuff like that. My questions What is the benefit of singleton pattern? Which thing is most apt here? All static methods or a singleton pattern? Please compare both of them. regards shahensha P.S. The database is bigger than this. Here I am talking only about the tables which I'll be using for storing User Information.

  Read the article

< Previous Page | 179 180 181 182 183 184 185 186 187 188 189 190  | Next Page >