Search Results

Search found 13550 results on 542 pages for 'processing js'.

Page 29/542 | < Previous Page | 25 26 27 28 29 30 31 32 33 34 35 36  | Next Page >

  • How can chunks be allocated in a node.js stream in object mode all at once?

    - by Quentin Engles
    I can see how buffers, and strings can be sent as chunks, but I'm having a problem thinking about how streams can be dealt when working in object mode. Say I have a byte stream from an http request message. I want to take that message, parse, and then transform it into one big object. I already know how to parse the message. What I'm wondering is if the message is big so it has many chunks, but I want to make one object for the output how can I make sure the data event waits for the whole thing? Is this just a matter of not using the push method until the chunked data has finished being sent? That would then restrict the stream data output to a smaller object which I think I'm fine with for now. As an added condition the larger data will be reduced in size after the the transform.

    Read the article

  • CSS or JS max. character <h2> and replace end with "..."

    - by cr0z3r
    Hey I assume my title basically summed it all up. I have a <h2> title, and I want it to have a max character property, be it CSS or javascript, so that whenever this maximum limit is passed, the title's end is replaced by ... (three dots). Thank you very much in advance. An example can be viewed here: http://themeforest.net/forums/thread/now-accepting-bargain-submissions/23205 (see the title) P.S. Any idea why I had to create a new user? the login-feature through google doesn't recognize my previous user :(

    Read the article

  • how can i search a lots of .js and .php files for a specific phrase?

    - by Haroldo
    Windows has a go at it but only gets a few when i seach a directory. Is there an IDE or similar that allows for searching within the files of an entire directory? for example, if I need to make sure no files require to a redundant class (old_class.php) I'd like to search for 'old_class.php' or alternatively if anyone knows a way to do this in Aptana (my text editor of choice) that would be amazing...

    Read the article

  • Javascript not executing (I included format.js)

    - by Brandon
    I added format.js to my controller, yet I still cannot get the js in index.js.erb to execute when I view my index page. The only thing I can figure out is that it must be because of the model name. I had to add ActiveSupport::Inflector.inflections do |inflect| inflect.irregular 'business', 'businesses' end to my inflections.rb file...because my model is called Business. my views/js are located at views/businesses/* Please help before I pull my hair out! All I have in the index.js.erb file is: alert(1); Obviously the goal is that I will get an alert when I finally get the issue fixed, letting me know it is working.

    Read the article

  • node.js: encrypting data that needs to be decrypted?

    - by fancy
    We are using bcrypt for passwords and data that never needs to be decrypted. What should do to protect other user information that does. For this example lets say that we didn't want a users real name to be in plain text in case someone was to obtain the db. This is somewhat sensitive data but also needs to be called from time to time and displayed in plain text. Is there a simple way to do this?

    Read the article

  • setting variables and values in html & js

    - by air
    i have one js file in that js file i have following variables var image_path="images"; var style_path="style"; i want to use these variables in html file(s) like in image statement <img src="path from js/logo.gif"> or in style sheet statement <link rel="stylesheet" href="path from js/constant.css" type="text/css" /> Basic idea behind this is: if we change name of image folder or path of image folder we only do change in one JS file not 1000 html files. same for style sheet. or any other way to do same in java script or Jquery Thanks

    Read the article

  • How much overhead is there in persistent connections?

    - by nynex
    Ok so I'm musing over a little side project I want to start. Essentially its a multi-session web based FTP client. Multi-session in that you can log into several FTP servers at the same time and perform operations like moving a file from one FTP server to another. I'm doing this mainly to brush up on the new webdev technologies, particularly websockets. I'm using node.js + socket.io to keep a persistent bi-directional connection between the web browser and the web server. The web server will also have persistent connections to each FTP server the user has logged into. So if there are 100 concurrent users each logged into 5 ftp accounts, the web server will have 100 websocket connections + 500 ftp connections. Is servicing 600 connections a lot? I know it depends on the hardware resources of the server but is something like this doable on a budget? Are there more efficient means of doing something like this? I know its unlikely that this project will really get popular but I want it to scale well regardless. Thanks for any help, I've still got a lot to learn.

    Read the article

  • How to unit test models in MVC / MVR app?

    - by BBnyc
    I'm building a node.js web app and am trying to do so for the first time in a test driven fashion. I'm using nodeunit for testing, which I find allows me to write tests quickly and painlessly. In this particular app, the heavy lifting primarily involves translating SQL data into complex Javascript object and serving them to the front-end via json. Likewise, the app also spends a great deal of code validating and translating complex, multidimensional Javascript objects it receives from the front-end into SQL rows. Hence I have used a fat model design for the app -- most of the real code resides in the models, where the data translation happens. What's the best approach to test such models with unit tests? I mean in particular the methods that have create javascript objects from the SQL rows and serve them to the front-end. Right now what I'm doing is making particular requests of my models with the unit tests and checking the returned data for all of the fields that should be there. However I have a suspicion that this is not the most robust kind of testing I could be doing. My current testing design also means I have to package my app code with some dummy data so that my tests can anticipate the kind of data that the app should be returning when tests run.

    Read the article

  • why are transaction monitors on decline? or are they?

    - by mrkafk
    http://www.itjobswatch.co.uk/jobs/uk/cics.do http://www.itjobswatch.co.uk/jobs/uk/tuxedo.do Look at the demand for programmers (% of job ads that the keyword appears), first graph under the table. It seems like demand for CICS, Tuxedo has fallen from 2.5%/1% respectively to almost zero. To me, it seems bizarre: now we have more networked and internet enabled machines than ever before. And most of them are talking to some kind of database. So it would seem that use of products whose developers spent last 20-30 years working on distributing and coordinating and optimizing transactions should be on the rise. And it appears they're not. I can see a few causes but can't tell whether they are true: we forgot that concurrency and distribution are really hard, and redoing it all by ourselves, in Java, badly. Erlang killed them all. Projects nowadays have changed character, like most business software has already been built and we're all doing internet services, using stuff like Node.js, Erlang, Haskell. (I've used RabbitMQ which is written in Erlang, "but it was small specialized side project" kind of thing). BigData is the emphasis now and BigData doesn't need transactions very much (?). None of those explanations seem particularly convincing to me, which is why I'm looking for better one. Anyone?

    Read the article

  • How do I make cars on a one-dimensional track avoid collisions?

    - by user990827
    Using three.js, I use a simple spline to represent a road. Cars can only move forward on the spline. A car should be able to slow-down behind a slow moving car. I know how to calculate the distance between 2 cars, but how to calculate the proper speed in each game update? At the moment I simply do something like this: this.speed += (this.maxSpeed - this.speed) * 0.02; // linear interpolation to maxSpeed // the position on the spline (0.0 - 1.0) this.position += this.speed / this.road.spline.getLength(); This works. But how to implement the slow-down part? // transform from floats (0.0 - 1.0) into actual units var carInFrontPosition = carInFront.position * this.road.spline.getLength(); var myPosition = this.position * this.road.spline.getLength(); var distance = carInFrontPosition - myPosition; // WHAT TO DO HERE WITH THE DISTANCE? // HOW TO CALCULATE MY NEW SPEED? Obviously I have to somehow take current speed of the cars into account for calculation. Besides different maxSpeeds, I want each car to also have a different mass (causing it to accelerate slower/faster). But this mass has to be then also taken into account for braking (slowing down) so they don't crash into each other.

    Read the article

  • Is the XML processing instructions node mandatory ?

    - by ereOn
    I had a discussion with a colleague of mine about the XML processing instructions node (I'm talking about this = <?xml version="1.0" encoding="UTF-8"?>). I believe that for something to be called "valid XML", it requires a processing instructions node. My colleague states that the processing instruction node is optionnal, since the default encoding is UTF-8 and the version is always 1.0. This make sense, but what does the standard says ? In short, given the following file: <books> <book id="1"><title>Title</title></book> </book> Can we say that: It is valid XML ? It is a valid XML node ? It is a valid XML document ? Thank you very much.

    Read the article

  • ASP.NET MVC2: Client-side validation not working with Start.js

    - by Shaggy13spe
    Ok, this is strange. I would hope it's something I'm doing wrong and not that MS has two technologies that simply don't work together. (UPDATE: See bottom of post for Script tag order in HEAD section) I'm trying to use the dataView template and client-side validation. If I include a reference to: <script src="http://ajax.microsoft.com/ajax/beta/0911/Start.js" type="text/javascript"></script> by itself, the dataview template works fine. but if I put in the following references: <script src="http://ajax.microsoft.com/ajax/jquery.validate/1.7/jquery.validate.min.js" type="text/javascript"></script> <script src="../../Scripts/MicrosoftAjax.js" type="text/javascript"></script> <script src="../../Scripts/MicrosoftMvcAjax.js" type="text/javascript"></script> <script src="../../Scripts/MicrosoftMvcValidation.js" type="text/javascript"></script> then I get the following error: > Error: Type._registerScript is not a > function Source File: > http://ajax.microsoft.com/ajax/beta/0911/MicrosoftAjaxTemplates.js > Line: 1 and: > Error: Sys.get("$listings") is null > Source File: > http://localhost:12370/Listings Line: > 76 Here's the code calling the dataview: $(document).ready(function () { LoadMap(); Sys.require([Sys.components.dataView, Sys.scripts.jQuery], function() { $("#listings").dataView(); Sys.get("$listings").set_data(listings.Data); updateMap(listings.Data); }); }); I would really appreciate any help with this one. Thanks! UPDATE: I've tried moving around the order of the last 4 script tags, but to no avail.

    Read the article

  • how to combine widget webapp framework with SEO-friendly CSS and JS files

    - by Ali
    Hi guys, I'm writing a webapp using Zend framework and a homebrew widget system. Every widget has a controller and can choose to render one of many views if it chooses. This really helps us modularize and reconfigure and reuse the widgets anywhere on the site. The Problem is that the views of each widget contain their own JS and CSS code, which leads to very messy HTML code when the whole page is put together. You get pockets of style and script tags everywhere. This is bad for a lot of different reasons as I'm sure you know, but it has a profound effect on our SEO as well. Several solutions that I've been able to come up with: Separate the CSS and JS of every view of every widget into its own file - this has serious drawbacks for load times (many more resources have to be loaded separately) and it makes coding very difficult as now you have to have 3-4 files open just to edit a widget. combine the all the widget CSS into a single file (same with JS) - would also lead to a massive load when someone enters the site, mixes up the CSS and the JS for all widgets so it's harder to keep track of them, and other problems that I'm sure you can think of. Create a system that uses method 1 (separate CSS and JS for every widget), when delivering the page, stitches all CSS and JS together. This obviously needs more processing time and of course the creation of such a system, etc. My Question is what you guys think of these solutions or if there are pre-existing solutions that you know of (or any tech that might help) solve this problem. I really appreciate all of your thoughts and comments!! Thanks guys, Ali

    Read the article

  • Rails: Rendered JS file doesn't execute using UJS

    - by Hassinus
    I would like to display a Rails edit form using JS instead of redirecting with HTML. To do this, I use UJS for the edit link: <%= link_to "Edit user info", edit_user_path(1), :remote => true %> Then, the "edit" action of User controller is like this (simplified version): controllers/users_controller.rb: def edit # Step 1: Get the edit HTML form @html = render_to_string(:template => "users/edit.html") # Step 2: Use JS to display the form in the correct place render "users/edit.js" end As you may guess, I have two views: The html version of "edit" action which contains the form in HTML format. Let's consider a test version: views/users/edit.html.erb: <h1>This is just a test</h1> The js version that will display the form in the correct place, using jQuery for example. Again, for test purpose, let's just popup the html text: views/users/edit.js.erb: alert("<%= @html %>"); The problem is that nothing is executed (no popup) Using the inspector (from Chrome web browser), I get the response as text format: alert("<h1>This is just a test</h1>"); Do you have any idea? Why do the rendered JS is not executed? Thanks in advance.

    Read the article

  • JS Worm : how to find the entry point

    - by Cédric Girard
    Hi, my site is tagged as dangerous by Google / StopBadware.org, and I found this in severals js/html files : <script type="text/javascript" src="http://oployau.fancountblogger.com:8080/Gigahertz.js"></script> <!--a0e2c33acd6c12bdc9e3f3ba50c98197--> I cleaned severals files, I restore a backup but how to understand how the worm had been installed? What can I look for in log files? This server, a Centos 5, is only used as an apache server, with ours programs, a tikiwiki, a drupal installed. Thanks Cédric

    Read the article

  • nginx can't load images,css,js

    - by EquinoX
    When I point to a URL in nginx where it has images extension such as: http://50.56.81.42/phpMyAdmin/themes/original/img/logo_right.png (as example) it gives me the 404 error as it can't find the file, but the file is actually there. What is potentially wrong? UPDATE: Here's the error log that I was able to pull out: 2011/02/27 05:53:29 [error] 18679#0: *225 open() "/usr/local/nginx/html/phpMyAdmin/js/mooRainbow/mooRainbow.css" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/js/mooRainbow/mooRainbow.css HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:53:29 [error] 18679#0: *226 open() "/usr/local/nginx/html/phpMyAdmin/print.css" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/print.css HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:53:29 [error] 18679#0: *228 open() "/usr/local/nginx/html/phpMyAdmin/themes/original/img/logo_right.png" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/themes/original/img/logo_right.png HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:53:29 [error] 18679#0: *223 open() "/usr/local/nginx/html/phpMyAdmin/themes/original/img/b_help.png" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/themes/original/img/b_help.png HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:53:29 [error] 18679#0: *227 open() "/usr/local/nginx/html/phpMyAdmin/themes/original/img/s_warn.png" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/themes/original/img/s_warn.png HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:53:29 [error] 18679#0: *227 open() "/usr/local/nginx/html/phpMyAdmin/favicon.ico" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/favicon.ico HTTP/1.1", host: "50.56.81.42" 2011/02/27 05:54:39 [error] 18679#0: *237 open() "/usr/local/nginx/html/phpMyAdmin/print.css" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/print.css HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:54:39 [error] 18679#0: *235 open() "/usr/local/nginx/html/phpMyAdmin/js/mooRainbow/mooRainbow.css" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/js/mooRainbow/mooRainbow.css HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:54:39 [error] 18679#0: *238 open() "/usr/local/nginx/html/phpMyAdmin/themes/original/img/logo_right.png" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/themes/original/img/logo_right.png HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:54:39 [error] 18679#0: *239 open() "/usr/local/nginx/html/phpMyAdmin/themes/original/img/b_help.png" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/themes/original/img/b_help.png HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:54:39 [error] 18679#0: *233 open() "/usr/local/nginx/html/phpMyAdmin/themes/original/img/s_warn.png" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/themes/original/img/s_warn.png HTTP/1.1", host: "50.56.81.42", referrer: "http://50.56.81.42/phpMyAdmin/main.php" 2011/02/27 05:54:39 [error] 18679#0: *233 open() "/usr/local/nginx/html/phpMyAdmin/favicon.ico" failed (2: No such file or directory), client: 70.176.18.156, server: localhost, request: "GET /phpMyAdmin/favicon.ico HTTP/1.1", host: "50.56.81.42" Here's my nginx.conf file, in case I am missing something: #user nobody; worker_processes 1; #error_log logs/error.log; #error_log logs/error.log notice; #error_log logs/error.log info; #pid logs/nginx.pid; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; #log_format main '$remote_addr - $remote_user [$time_local] "$request" ' # '$status $body_bytes_sent "$http_referer" ' # '"$http_user_agent" "$http_x_forwarded_for"'; #access_log logs/access.log main; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; #gzip on; server { listen 80; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / { root html; index index.html index.htm; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html # error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } location ~ \.(js|css|png|jpg|jpeg|gif|ico|html)$ { expires max; } # proxy the PHP scripts to Apache listening on 127.0.0.1:80 # #location ~ \.php$ { # proxy_pass http://127.0.0.1; #} # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000 # location ~ \.php$ { root /usr/share/nginx/html; fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME /usr/share/nginx/html$fastcgi_script_name; include fastcgi_params; } # deny access to .htaccess files, if Apache's document root # concurs with nginx's one location ~ /\.ht { deny all; } } # another virtual host using mix of IP-, name-, and port-based configuration # #server { # listen 8000; # listen somename:8080; # server_name somename alias another.alias; # location / { # root html; # index index.html index.htm; # } #} # HTTPS server # #server { # listen 443; # server_name localhost; # ssl on; # ssl_certificate cert.pem; # ssl_certificate_key cert.key; # ssl_session_timeout 5m; # ssl_protocols SSLv2 SSLv3 TLSv1; # ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP; # ssl_prefer_server_ciphers on; # location / { # root html; # index index.html index.htm; # } #} } What does this mean? It can't pull out the .css, etc....

    Read the article

  • New XEN Server, Intel i7, Errors were encountered while processing: xen-linux-system-amd64

    - by Sheldon
    I have just got a new machine to run XEN VM's on, it has an Intel i7 processor: - Intel Haswell Core i7-4790 3.6GHz 8MB LGA1150 I have setup the host with the current 6.2.0 I have set up a new Debian 7 64bit VM and any package I try and run fails with the following errors: Errors were encountered while processing: xen-utils-common xen-utils-4.1 xen-system-amd64 xen-linux-system-3.2.0-4-amd64 xen-linux-system-amd64 E: Sub-process /usr/bin/dpkg returned an error code (1) Excuse my noob-ness but should it even be running an AMD package ? Any ideas on how to fix this ? Thanks

    Read the article

  • bash completion processing gone bad, how to debug?

    - by msw
    It all started with a simple alias gv='gvim --remote-quiet' and now gv Space Tab gives nothing where it normally should give filenames. Oddly, alias gvi='gvim --remote-quiet' works as expected. I clearly have a workaround, but I'd like to know what is catching my gv for special processing. compopt is no help as gv shares the same settings as ls which does filename completion correctly. $compopt gv compopt +o bashdefault +o default +o dirnames -o filenames +o nospace +o plusdirs gv $ compopt ls compopt +o bashdefault +o default +o dirnames -o filenames +o nospace +o plusdirs ls The complete command is slightly more helpful but it doesn't tell me why my two characters got singled out for alteration: $ complete -p gv complete -o filenames -F _filedir_xspec gv $ complete -p ls complete -o filenames -F _longopt ls $ complete -p echo bash: complete: echo: no completion specification $ alias gvi='gvim --remote-silent' msw@tallguy:~/.gnupg$ complete -p gvi bash: complete: gvi: no completion specification Where did complete -o filenames -F _filedir_xpec gv come from?

    Read the article

  • Which databases support parallel processing across multiple servers?

    - by David
    I need a database engine that can utilize multiple servers for processing a single SQL query in parallel. So far I know that this is possible with the some engines, though none of them are feasible for me either because of pricing or missing features. The engines currently known to me are: MS SQL (enterprise) DB2 (enterprise) Oracle (enterprise) GridSQL Greenplum Which other engines have this feature? Do you have any experience with using this feature? Edit: I have now proposed a method for creating one myself. Any input is welcome. Edit: I have found another one: Informix Extended Parallel Server

    Read the article

  • What kind of CPU/GPU integration is offered by APUs?

    - by clabacchio
    I'm truly fascinated by the idea of GPGPU and using the GPU for heavy processing. I'm seeing that also APUs (Accelerated Processing Units, CPU+GPU on the same chip) are gaining a consistent popularity. Are all of the APUs using a GPGPU? Can it be used for processing? And is it seamless or it requires special code (like Cuda) to have the hard work made by the GPU? I'm not interested in bare graphic performance, but more about how much the GPU can accelerate the "normal" CPU work.

    Read the article

  • Blackberry Won't Sync: Says Processing

    - by Noah
    I have a blackberry storm 2 and I have it set up to sync, just like I've done with all the other ones in the company. They pull the address book/contacts from outlook, and aren't synced to an exchange server. I have everything setup and then when I hit synchronize it flashes "processing" the phone shows it trying to sync and then it is done in less than a second. It did warn me that the computer was not supplying enough power to charge the device and it said that I should make sure the drivers are correct. Also, I was warned that the device might not function properly down in the bottom right hand corner. Any ideas? I've uninstalled and reinstalled the blackberry software off the disc.

    Read the article

  • Processing files from a Content Distribution Network problem

    - by Derek
    From what I understand that CDNs are meant to physically cache your static files in multiple regions closer to your users. However, I've noticed a few websites that when a page is requested from their server, they grab the asset files from their cdn, process them (compress, minify, etc.) cache the results on their server and then send them to the user requesting the page. This doesn't make too much sense to me. Wouldn't processing the files on your server eliminate the gains from using a cdn? Is this a normal way of doing things, or am I not understanding the whole asset management concept?

    Read the article

  • Building a workstation computer for Image processing? [closed]

    - by echolab
    I am taking a gigapixel image my goal is 50gigapixel and shooting is almost done , i am doing some research to build a workstation so i can stitch images together , my questions is ! Could u suggest some dual cpu mainboard that works fine with xeon 5500+ , with 64GB+ ram support ? My other question is which hardware is most important in image processing , all i see in story of gigapixel panoramas is they have dual xeon and 32gb+ ram ? i wonder if i am doing this right , i mean they don't post information on graphic card , mainboard and stuff ! I did asked several websites , but nothing best answer was get some high-end workstation and plenty of hours , i don't want to purchase ready to use workstations, i wanna build it up Thanks in advance

    Read the article

  • Partition Wise Joins

    - by jean-pierre.dijcks
    Some say they are the holy grail of parallel computing and PWJ is the basis for a shared nothing system and the only join method that is available on a shared nothing system (yes this is oversimplified!). The magic in Oracle is of course that is one of many ways to join data. And yes, this is the old flexibility vs. simplicity discussion all over, so I won't go there... the point is that what you must do in a shared nothing system, you can do in Oracle with the same speed and methods. The Theory A partition wise join is a join between (for simplicity) two tables that are partitioned on the same column with the same partitioning scheme. In shared nothing this is effectively hard partitioning locating data on a specific node / storage combo. In Oracle is is logical partitioning. If you now join the two tables on that partitioned column you can break up the join in smaller joins exactly along the partitions in the data. Since they are partitioned (grouped) into the same buckets, all values required to do the join live in the equivalent bucket on either sides. No need to talk to anyone else, no need to redistribute data to anyone else... in short, the optimal join method for parallel processing of two large data sets. PWJ's in Oracle Since we do not hard partition the data across nodes in Oracle we use the Partitioning option to the database to create the buckets, then set the Degree of Parallelism (or run Auto DOP - see here) and get our PWJs. The main questions always asked are: How many partitions should I create? What should my DOP be? In a shared nothing system the answer is of course, as many partitions as there are nodes which will be your DOP. In Oracle we do want you to look at the workload and concurrency, and once you know that to understand the following rules of thumb. Within Oracle we have more ways of joining of data, so it is important to understand some of the PWJ ideas and what it means if you have an uneven distribution across processes. Assume we have a simple scenario where we partition the data on a hash key resulting in 4 hash partitions (H1 -H4). We have 2 parallel processes that have been tasked with reading these partitions (P1 - P2). The work is evenly divided assuming the partitions are the same size and we can scan this in time t1 as shown below. Now assume that we have changed the system and have a 5th partition but still have our 2 workers P1 and P2. The time it takes is actually 50% more assuming the 5th partition has the same size as the original H1 - H4 partitions. In other words to scan these 5 partitions, the time t2 it takes is not 1/5th more expensive, it is a lot more expensive and some other join plans may now start to look exciting to the optimizer. Just to post the disclaimer, it is not as simple as I state it here, but you get the idea on how much more expensive this plan may now look... Based on this little example there are a few rules of thumb to follow to get the partition wise joins. First, choose a DOP that is a factor of two (2). So always choose something like 2, 4, 8, 16, 32 and so on... Second, choose a number of partitions that is larger or equal to 2* DOP. Third, make sure the number of partitions is divisible through 2 without orphans. This is also known as an even number... Fourth, choose a stable partition count strategy, which is typically hash, which can be a sub partitioning strategy rather than the main strategy (range - hash is a popular one). Fifth, make sure you do this on the join key between the two large tables you want to join (and this should be the obvious one...). Translating this into an example: DOP = 8 (determined based on concurrency or by using Auto DOP with a cap due to concurrency) says that the number of partitions >= 16. Number of hash (sub) partitions = 32, which gives each process four partitions to work on. This number is somewhat arbitrary and depends on your data and system. In this case my main reasoning is that if you get more room on the box you can easily move the DOP for the query to 16 without repartitioning... and of course it makes for no leftovers on the table... And yes, we recommend up-to-date statistics. And before you start complaining, do read this post on a cool way to do stats in 11.

    Read the article

< Previous Page | 25 26 27 28 29 30 31 32 33 34 35 36  | Next Page >