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  • Transmitting Form Data from the Client to the Web Server

    The steps involved in transmitting form data from the client to the web server User loads web form User enters data in to web form fields User clicks submit On submit page validates fields using JavaScript. If validation errors are found then the validation script stops the browser from canceling posting the data to the web server and displays error messages as needed If the form passes the data validation process then the browser will URL encode the values of every field and post it to the server.  The server reads the posted data from the query string and then again validates the data just to ensure data consistency and to prevent any non-validated data because JavaScript was turned off on the clients browser from being inserted in to a database or passed on to other process If the data passes the second validation check then the server side code will continue with the requested processes

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  • SQL Peer-to-Peer Dynamic Structured Data Processing Collaboration

    Unstructured and XML semi-structured data is now used more than structured data. But fixed structured data still keeps businesses running day in and day out, which requires consistent predictable highly principled processing for correct results. For this reason, it would be very useful to have a general purpose SQL peer-to-peer collaboration capability that can utilize highly principled hierarchical data processing and its flexible and advanced structured processing to support dynamically structured data and its dynamic structured processing. This flexible dynamic structured processing can change the structure of the data as necessary for the required processing while preserving the relational and hierarchical data principles. This processing will perform freely across remote unrelated peer locations anytime and transparently process unpredictable and unknown structured data and data type changes automatically for immediate processing using automatic metadata maintenance.

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  • Is there a data structure for this type of list/map?

    - by Nick
    Perhaps there's a name for what I want, but I'm not aware of it. I need something similar to a LinkedHashMap in Java, but where it returns the 'previous' value if there's no value at the specified key. That is, I have a list of objects stored by an integer key (which is in units of time in my case): ; key->value 10->A 15->B 20->C So, if I were to query for a value for key 0-9, it would return null. The special part is if I queried for something 10 <= i <= 14 it would return A. Or, for i = 20, it would return C. Is there a data structure for this?

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  • is mysql index useful on column 'state' when only doing bit-operations on the column?

    - by Geert-Jan
    I have a lot of domain entities (stored in mysql) which undergo lots of different operations. Each operation is executed from a different program. I need to keep (flow)-state for these entities which I implemented in as a long field 'flowstate' used as a bitset. to query mysql for entities which have undergone a certain operation I do something like: select * from entities where state >> 7 & 1 = 1 Indicating bit 7 (cooresponding to operation 7) has run. (<-- simplified) Anyway, I really didn't pay attention to the performance implications of this setup in the beginning, and I think I'm in a bit of trouble since queries as the above run pretty slow. What I'd like to know: Does an mysql index on 'flowstate' help at all? After all it's not a single value Mysql can quickly find using a binary sort or whatever. If it doesn't, are there any other things I could do to speed things up? . Are there special 'mask-indices' for fields with use-cases as the above? TIA, Geert-jan

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  • How can I get back my privilege to create a new database in MySQL?

    - by Steven
    I can not use MySQL. MySQL is on my local computer. Currently I added skip-grant-tables in My.ini so I can use MySQL. But I have no privilege to create a new database. My problem is tough, although I asked related questions on SO, but no answer can resolve my problem. I almost give up. So I lower my expectation. I am developing a website, so I need to create database, tables and operate tables. You don't have to consider security. Is there a simple solution that can give me privilege to create a new database? Maybe by adding some command in my.ini or something? You won't need to completely resolve my problem. Maybe after the development, I will upload the database and tables to another server(The current database server is my personal computer, windows XP) so I can uninstall and reinstall MySQL. The root of problem is that I lack privileges.

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  • How do I get PHP variables from this MySQL query?

    - by CT
    I am working on an Asset Database problem using PHP / MySQL. In this script I would like to search my assets by an asset id and have it return all related fields. First I query the database asset table and find the asset's type. Then depending on the type I run 1 of 3 queries. <?php //make database connect mysql_connect("localhost", "asset_db", "asset_db") or die(mysql_error()); mysql_select_db("asset_db") or die(mysql_error()); //get type of asset $type = mysql_query(" SELECT asset.type From asset WHERE asset.id = 93120 ") or die(mysql_error()); switch ($type){ case "Server": //do some stuff that involves a mysql query mysql_query(" SELECT asset.id ,asset.company ,asset.location ,asset.purchase_date ,asset.purchase_order ,asset.value ,asset.type ,asset.notes ,server.manufacturer ,server.model ,server.serial_number ,server.esc ,server.user ,server.prev_user ,server.warranty FROM asset LEFT JOIN server ON server.id = asset.id WHERE asset.id = 93120 "); break; case "Laptop": //do some stuff that involves a mysql query mysql_query(" SELECT asset.id ,asset.company ,asset.location ,asset.purchase_date ,asset.purchase_order ,asset.value ,asset.type ,asset.notes ,laptop.manufacturer ,laptop.model ,laptop.serial_number ,laptop.esc ,laptop.user ,laptop.prev_user ,laptop.warranty FROM asset LEFT JOIN laptop ON laptop.id = asset.id WHERE asset.id = 93120 "); break; case "Desktop": //do some stuff that involves a mysql query mysql_query(" SELECT asset.id ,asset.company ,asset.location ,asset.purchase_date ,asset.purchase_order ,asset.value ,asset.type ,asset.notes ,desktop.manufacturer ,desktop.model ,desktop.serial_number ,desktop.esc ,desktop.user ,desktop.prev_user ,desktop.warranty FROM asset LEFT JOIN desktop ON desktop.id = asset.id WHERE asset.id = 93120 "); break; } ?> So far I am able to get asset.type into $type. How would I go about getting the rest of the variables (laptop.model to $model, asset.notes to $notes and so on)? Thank you.

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  • Is it a good idea to use MySQL and Neo4j together?

    - by Sanoj
    I will make an application with a lot of similar items (millions), and I would like to store them in a MySQL database, because I would like to do a lot of statistics and search on specific values for specific columns. But at the same time, I will store relations between all the items, that are related in many connected binary-tree-like structures (transitive closure), and relation databases are not good at that kind of structures, so I would like to store all relations in Neo4j which have good performance for this kind of data. My plan is to have all data except the relations in the MySQL database and all relations with item_id stored in the Neo4j database. When I want to lookup a tree, I first search the Neo4j for all the item_id:s in the tree, then I search the MySQL-database for all the specified items in a query that would look like: SELECT * FROM items WHERE item_id = 45 OR item_id = 345435 OR item_id = 343 OR item_id = 78 OR item_id = 4522 OR item_id = 676 OR item_id = 443 OR item_id = 4255 OR item_id = 4345 Is this a good idea, or am I very wrong? I haven't used graph-databases before. Are there any better approaches to my problem? How would the MySQL-query perform in this case?

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  • What's the best way to get a bunch of rows from MySQL if you have an array of integer primary keys?

    - by Evan P.
    I have a MySQL table with an auto-incremented integer primary key. I want to get a bunch of rows from the table based on an array of integers I have in memory in my program. The array ranges from a handful to about 1000 items. What's the most efficient query syntax to get the rows? I can think of a few: "SELECT * FROM thetable WHERE id IN (1, 2, 3, 4, 5)" (this is what I do now) "SELECT * FROM thetable where id = 1 OR id = 2 OR id = 3" Multiple queries of the form "SELECT * FROM thetable WHERE id = 1". Probably the most friendly to the query cache, but expensive due to having lots of query parsing. A union, like "SELECT * FROM thetable WHERE id = 1 UNION SELECT * FROM thetable WHERE id = 2 ..." I'm not sure if MySQL caches the results of each query; it's also the most verbose format. I think using the NoSQL interface in MySQL 5.6+ would be the most efficient way to do this, but I'm not yet up to MySQL 5.6.

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  • [PHP] MySql Proccesslist filled with "Sleep" Entries leading to "To many Connections" ?

    - by edorian
    Hi, i'd like to ask your help on a longstanding issue with php/mysql connections. Every time i execute a "SHOW PROCESSLIST" command it shows me about 400 idle (Status: Sleep) connections to the database Server emerging from our 5 Webservers. That never was much of a problem (and i didn't find a quick solution) until recently traffic numbers increased and since then MySql reports the "to many connections" Problems repeatedly, even so 350+ of those connections are in "sleep" state. Also a server can't get a mysql connection even if there are sleeping connection to that same server. All those connections vanish when a apache server is restated. The PHP Code used to create the Database connections uses the normal "mysql" Module, the "mysqli" Module, PEAR::DB and Zend Framework Db Adapter. (Different projects). NONE of the projects uses persistent connections. Raising the connection-limit is possible but doesn't seem like a good solution since it's 450 now and there are only 20-100 "real" connections at a time anyways. My question: Why are there so many connections in sleep state and how can i prevent that. Thank you for your time, if theres anything unclear or missing please let me know

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  • InnoDB: Error: log file ./ib_logfile0 is of different size

    - by jack
    I just added the following lines in /etc/mysql/my.cnf after I converted one database to use InnoDB engine. innodb_buffer_pool_size = 2560M innodb_log_file_size = 256M innodb_log_buffer_size = 8M innodb_flush_log_at_trx_commit = 2 innodb_thread_concurrency = 16 innodb_flush_method = O_DIRECT But it raise "ERROR 2013 (HY000) at line 2: Lost connection to MySQL server during query" error restarting mysqld. And mysql error log shows the following InnoDB: Error: log file ./ib_logfile0 is of different size 0 5242880 bytes InnoDB: than specified in the .cnf file 0 268435456 bytes! 100118 20:52:52 [ERROR] Plugin 'InnoDB' init function returned error. 100118 20:52:52 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 100118 20:52:52 [ERROR] Unknown/unsupported table type: InnoDB 100118 20:52:52 [ERROR] Aborting So I commented out this line # innodb_log_file_size = 256M And it restarted mysql successfully. I wonder what's the "5242880 bytes of log file" showed in mysql error? It's the first database on InnoDB engine on this server so when and where is that log file created? In this case, how can I enable innodb_log_file_size directive in my.cnf? EDIT I tried to delete /var/lib/mysql/ib_logfile0 and restart mysqld but it still failed. It now shows the following in error log. 100118 21:27:11 InnoDB: Log file ./ib_logfile0 did not exist: new to be created InnoDB: Setting log file ./ib_logfile0 size to 256 MB InnoDB: Database physically writes the file full: wait... InnoDB: Progress in MB: 100 200 InnoDB: Error: log file ./ib_logfile1 is of different size 0 5242880 bytes InnoDB: than specified in the .cnf file 0 268435456 bytes! Resolution It works now after deleted both ib_logfile0 and ib_logfile1 in /var/lib/mysql

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  • On a failing hard drive, I am able to view data but unable to copy it - why?

    - by Tom
    I have a 2.5" external hard drive that is failing. It's not making the expected 'clicking' noise that most hard drives and I am able to view the data, but I am unable to actually retrieve the data. I attempted to use SpinRite in order to access the data on the drive, but it didn't like the external drive. When I view the drive's property page, the drive shows that it's used space is at 100% and that it has 0 bytes available; however, the progress indicator under the drive icon in Windows Explorer shows that it's roughly 50% full (which is correct). When I attempt to run Windows' "Error Checking" tool and attempt to "scan for an attempt recovery of bad sectors," the tool begins to run then immediately closes with no error message. I am able to browse the contents of the drive using Windows Explorer. When I begin to try copying any given single file, the copy process begins, an indicator starts, and then the copy fails with no real error message. The Disk Management page in Computer Management under Control Panel also shows this drive has being 'Healthy.' I dropped the drive off at a data recovery store and they said that "The data seems to be intact, but an internal failure is preventing any information from being retrieved." They offered to provide me references to a data recovery specialist. I've also attempted to run CHKDSK on the drive (with and without arguments) but it returns the following error: The type of the filesystem is RAW. CHKDSK is not available for RAW drives. Before going the route of more expensive data recovery, I'm wondering if these symptoms sound familiar to anyone? Other questions... I'm willing to continue trying tools such as TestDisk and/or PhotoRec (as the majority of the data that I'd like to salvage are photos) but how long I should expect either tool to run given approximately 400GB of data? I'm also comfortable using Linux so I welcome any suggestions for utilities or tools and strategies with which you've had success.

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  • jdbc4 CommunicationsException

    - by letronje
    I have a machine running a java app talking to a mysql instance running on the same instance. the app uses jdbc4 drivers from mysql. I keep getting com.mysql.jdbc.exceptions.jdbc4.CommunicationsException at random times. Here is the whole message. Could not open JDBC Connection for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was25899 milliseconds ago.The last packet sent successfully to the server was 25899 milliseconds ago, which is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem. For mysql, the value of global 'wait_timeout' and 'interactive_timeout' is set to 3600 seconds and 'connect_timeout' is set to 60 secs. the wait timeout value is much higher than the 26 secs(25899 msecs). mentioned in the exception trace. I use dbcp for connection pooling and here is spring bean config for the datasource. <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource" > <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/db"/> <property name="username" value="xxx"/> <property name="password" value="xxx" /> <property name="poolPreparedStatements" value="false" /> <property name="maxActive" value="3" /> <property name="maxIdle" value="3" /> </bean> Any idea why this could be happening? Will using c3p0 solve the problem ?

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  • mysql_query missing during installation

    - by Arsenal
    Hi, I'm trying to install the pdo_mysql extension... I managed to install it succesfully, but ever since I upgraded mysql to 5.1.34 (using rpm packages) it seems to have gone down so I tried to reinstall it. However it seems to crash on ./configure as it gives 'mysql_query not found' error: configure:3961: checking for mysql_query in -lmysqlclient configure:3991: gcc -o conftest -g -O2 -I/usr/local/include/php -Wl,- rpath,/usr/lib/mysql -L/usr/lib/mysql -lmysqlclient -lz -lcrypt -lnsl -lm -lmygcc conftest.c -lmysqlclient -rdynamic -L/usr/lib/mysql -lmysqlclient -lz -lcrypt -lnsl -lm - lmygcc >&5 /usr/bin/ld: skipping incompatible /usr/lib/mysql/libmysqlclient.a when searching for -lmysqlclient /usr/bin/ld: skipping incompatible /usr/lib/mysql/libmysqlclient.a when searching for -lmysqlclient /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../../libmysqlclient.so when searching for -lmysqlclient /usr/bin/ld: skipping incompatible /usr/lib/libmysqlclient.so when searching for -lmysqlclient /usr/bin/ld: cannot find -lmysqlclient collect2: ld returned 1 exit status configure:3997: $? = 1 configure: failed program was: | /* confdefs.h. */ ... In that file there seems to be a mysql_query(); statement. I'm pretty sure mysql_query works however since all of my websites are running normally. However the current setup is a mess (previous students kind of messed it up) and there are a whole lot of libmysqclient's in /etc: libmysqlclient.so.10.0.0 libmysqlclient.so.12.0.0 libmysqlclient.so.14.0.0 libmysqlclient.so.15.0.0 libmysqlclient.so.16.0.0 libmysqlclient_r.so.10.0.0 libmysqlclient_r.so.12.0.0 libmysqlclient_r.so.14.0.0 libmysqlclient_r.so.15.0.0 libmysqlclient_r.so.16.0.0 And just as much symlinks. Does anyone know how to get this right? Many thanks! (oh, and no pecl install pdo_mysql doesn't get me any further). I'm runnnig CentOS 4 with php 5.2.9 compiled from source and MySQL 5.1.34

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  • jdbc4 CommunicationsException

    - by letronje
    I have a machine running a java app talking to a mysql instance running on the same instance. the app uses jdbc4 drivers from mysql. I keep getting com.mysql.jdbc.exceptions.jdbc4.CommunicationsException at random times. Here is the whole message. Could not open JDBC Connection for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was25899 milliseconds ago.The last packet sent successfully to the server was 25899 milliseconds ago, which is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to avoid this problem. For mysql, the value of global 'wait_timeout' and 'interactive_timeout' is set to 3600 seconds and 'connect_timeout' is set to 60 secs. the wait timeout value is much higher than the 26 secs(25899 msecs). mentioned in the exception trace. I use dbcp for connection pooling and here is spring bean config for the datasource. <bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource" > <property name="driverClassName" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/db"/> <property name="username" value="xxx"/> <property name="password" value="xxx" /> <property name="poolPreparedStatements" value="false" /> <property name="maxActive" value="3" /> <property name="maxIdle" value="3" /> </bean> Any idea why this could be happening? Will using c3p0 solve the problem ?

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  • MySQL Utility Users' Console Oerview

    - by rudrap
    MySQL Utility Users' Console (mysqluc): The MySQL Utilities Users' Console is designed to make using the utilities easier via a dedicated console. It helps us to use the utilities without worrying about the python and utility paths. Why do we need a special console? - It does provide a unique shell environment with command completion, help for each utility, user defined variables, and type completion for options. - You no longer have to type out the entire name of the utility. - You don't need to remember the name of a database utility you want to use. - You can define variables and reuse them in your utility commands. - It is possible to run utility command along with mysqluc and come out of the mysqluc console. Console commands: mysqluc> help Command Description ----------------------           --------------------------------------------------- help utilities                     Display list of all utilities supported. help <utility>                  Display help for a specific utility. help or help commands   Show this list. exit or quit                       Exit the console. set <variable>=<value>  Store a variable for recall in commands. show options                   Display list of options specified by the user on launch. show variables                 Display list of variables. <ENTER>                       Press ENTER to execute command. <ESCAPE>                     Press ESCAPE to clear the command entry. <DOWN>                       Press DOWN to retrieve the previous command. <UP>                               Press UP to retrieve the next command in history. <TAB>                            Press TAB for type completion of utility, option,or variable names. <TAB><TAB>                Press TAB twice for list of matching type completion (context sensitive). How do I use it? Pre-requisites: - Download the latest version of MySQL Workbench. - Mysql Servers are running. - Your Pythonpath is set. (e.g. Export PYTHONPATH=/...../mysql-utilities/) Check the Version of mysqluc Utility: /usr/bin/python mysqluc.py –version It should display something like this MySQL Utilities mysqluc.py version 1.1.0 - MySQL Workbench Distribution 5.2.44 Copyright (c) 2010, 2012 Oracle and/or its affiliates. All rights reserved. This program is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, to the extent permitted by law. Use of TAB to get the current utilities: mysqluc> mysqldb<TAB><TAB> Utility Description -------------        ------------------------------------------------------------ mysqldbcopy      copy databases from one server to another mysqldbexport    export metadata and data from databases mysqldbimport    import metadata and data from files mysqluc> mysqldbcopy –source=$se<TAB> Variable Value -------- ---------------------------------------------------------------------- server1 root@localhost:3306 server2 root@localhost:3307 you can see the variables starting with se and then decide which to use Run a utility via the console: /usr/bin/python mysqluc.py -e "mysqldbcopy --source=root@localhost:3306 --destination=root@localhost:3307 dbname" Get help for utilities in the console: mysqluc> help utilities Display help for a utility mysqluc> help mysqldbcopy Details about mysqldbcopy and its options set variables and use them in commands: mysqluc> set server1 = root@localhost:3306 mysqluc>show variables Variable Value -------- ---------------------------------------------------------------------- server1    root@localhost:3306 server2    root@localhost:3307 mysqluc> mysqldbcopy –source=$server1 –destination=$server2 dbname <Enter> Mysqldbcopy utility output will display. mysqluc>show options Display list of options specified by the user mysqluc SERVER=root@host123 VAR_A=57 -e "show variables" Variable Value -------- ----------------------------------------------------------------- SERVER root@host123 VAR_A 57 Finding option names for an Utility: mysqluc> mysqlserverclone --n Option Description ------------------- --------------------------------------------------------- --new-data=NEW_DATA the full path to the location of the data directory for the new instance --new-port=NEW_PORT the new port for the new instance - default=3307 --new-id=NEW_ID the server_id for the new instance - default=2 Limitations: User defined variables have a lifetime of the console run time.

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  • Is there any chance that my data will get silently corrupted with a robocopy SMB network transfer?

    - by Archagon
    I'm setting up a NAS box for the first time. At the moment, I have most of my data backed up to a few local hard drives, and I intend to transfer all the data to my NAS over ethernet once the RAID array is setup. Since this is all happening over the network, I'm a bit worried about my data getting corrupted silently during transfer. From what I understand, data generally doesn't get corrupted without notice on local transfers because a checksum is performed at some point by the drive or the OS. (This could be totally wrong.) Does the same thing happen with SMB, or is it up to the transferrer to check the integrity of their data? And if it doesn't happen with SMB, is there a protocol that does ensure data integrity? I know that rsync can checksum a transfer, but I'm on Windows and I already have a robocopy configuration that I like. Will my data be safe or do I have to use an external checksum tool to make sure?

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  • Freezes (not crashes) with GCD, blocks and Core Data

    - by Lukasz
    I have recently rewritten my Core Data driven database controller to use Grand Central Dispatch to manage fetching and importing in the background. Controller can operate on 2 NSManagedContext's: NSManagedObjectContext *mainMoc instance variable for main thread. this contexts is used only by quick access for UI by main thread or by dipatch_get_main_queue() global queue. NSManagedObjectContext *bgMoc for background tasks (importing and fetching data for NSFetchedresultsController for tables). This background tasks are fired ONLY by user defined queue: dispatch_queue_t bgQueue (instance variable in database controller object). Fetching data for tables is done in background to not block user UI when bigger or more complicated predicates are performed. Example fetching code for NSFetchedResultsController in my table view controllers: -(void)fetchData{ dispatch_async([CDdb db].bgQueue, ^{ NSError *error = nil; [[self.fetchedResultsController fetchRequest] setPredicate:self.predicate]; if (self.fetchedResultsController && ![self.fetchedResultsController performFetch:&error]) { NSSLog(@"Unresolved error in fetchData %@", error); } if (!initial_fetch_attampted)initial_fetch_attampted = YES; fetching = NO; dispatch_async(dispatch_get_main_queue(), ^{ [self.table reloadData]; [self.table scrollRectToVisible:CGRectMake(0, 0, 100, 20) animated:YES]; }); }); } // end of fetchData function bgMoc merges with mainMoc on save using NSManagedObjectContextDidSaveNotification: - (void)bgMocDidSave:(NSNotification *)saveNotification { // CDdb - bgMoc didsave - merging changes with main mainMoc dispatch_async(dispatch_get_main_queue(), ^{ [self.mainMoc mergeChangesFromContextDidSaveNotification:saveNotification]; // Extra notification for some other, potentially interested clients [[NSNotificationCenter defaultCenter] postNotificationName:DATABASE_SAVED_WITH_CHANGES object:saveNotification]; }); } - (void)mainMocDidSave:(NSNotification *)saveNotification { // CDdb - main mainMoc didSave - merging changes with bgMoc dispatch_async(self.bgQueue, ^{ [self.bgMoc mergeChangesFromContextDidSaveNotification:saveNotification]; }); } NSfetchedResultsController delegate has only one method implemented (for simplicity): - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { dispatch_async(dispatch_get_main_queue(), ^{ [self fetchData]; }); } This way I am trying to follow Apple recommendation for Core Data: 1 NSManagedObjectContext per thread. I know this pattern is not completely clean for at last 2 reasons: bgQueue not necessarily fires the same thread after suspension but since it is serial, it should not matter much (there is never 2 threads trying access bgMoc NSManagedObjectContext dedicated to it). Sometimes table view data source methods will ask NSFetchedResultsController for info from bgMoc (since fetch is done on bgQueue) like sections count, fetched objects in section count, etc.... Event with this flaws this approach works pretty well of the 95% of application running time until ... AND HERE GOES MY QUESTION: Sometimes, very randomly application freezes but not crashes. It does not response on any touch and the only way to get it back to live is to restart it completely (switching back to and from background does not help). No exception is thrown and nothing is printed to the console (I have Breakpoints set for all exception in Xcode). I have tried to debug it using Instruments (time profiles especially) to see if there is something hard going on on main thread but nothing is showing up. I am aware that GCD and Core Data are the main suspects here, but I have no idea how to track / debug this. Let me point out, that this also happens when I dispatch all the tasks to the queues asynchronously only (using dispatch_async everywhere). This makes me think it is not just standard deadlock. Is there any possibility or hints of how could I get more info what is going on? Some extra debug flags, Instruments magical tricks or build setting etc... Any suggestions on what could be the cause are very much appreciated as well as (or) pointers to how to implement background fetching for NSFetchedResultsController and background importing in better way.

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  • Tile Engine - Procedural generation, Data structures, Rendering methods - A lot of effort question!

    - by Trixmix
    Isometric Tile and GameObject rendering. To achive the desired looking game I need to take into consideration which tiles need to be drawn first and which last. What I used is a Object that is TileRenderQueue that you would give it a tile list and it will give you a queue on which ones to draw based on their Z coordinate, so that if the Z is higher then it needs to be drawn last. Now if you read above you would know that I want the location data to instead of being stored in the tile instance i want it to be that the index in the array is the location. and then maybe based on the array i could draw the tiles instead of taking a long time in for looping and ordering them by Z. This is the hardest part for me. It's hard for me to find a simple solution to the which one to draw when problem. Also there is the fact that if the X is larger than the gameobject where the X is larger needs to be drawn over the rest of the tiles and so on. Here is an example: All the parts work together to create an efficient engine so its important to me that you would answer all of the parts. I hope you will work on the answers hard just as much that I worked on this question! If there is any unclear part tell me so in the comments! Thanks for the help!

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  • NEW 2-Day Instructor Led Course on Oracle Data Mining Now Available!

    - by chberger
    A NEW 2-Day Instructor Led Course on Oracle Data Mining has been developed for customers and anyone wanting to learn more about data mining, predictive analytics and knowledge discovery inside the Oracle Database.  Course Objectives: Explain basic data mining concepts and describe the benefits of predictive analysis Understand primary data mining tasks, and describe the key steps of a data mining process Use the Oracle Data Miner to build,evaluate, and apply multiple data mining models Use Oracle Data Mining's predictions and insights to address many kinds of business problems, including: Predict individual behavior, Predict values, Find co-occurring events Learn how to deploy data mining results for real-time access by end-users Five reasons why you should attend this 2 day Oracle Data Mining Oracle University course. With Oracle Data Mining, a component of the Oracle Advanced Analytics Option, you will learn to gain insight and foresight to: Go beyond simple BI and dashboards about the past. This course will teach you about "data mining" and "predictive analytics", analytical techniques that can provide huge competitive advantage Take advantage of your data and investment in Oracle technology Leverage all the data in your data warehouse, customer data, service data, sales data, customer comments and other unstructured data, point of sale (POS) data, to build and deploy predictive models throughout the enterprise. Learn how to explore and understand your data and find patterns and relationships that were previously hidden Focus on solving strategic challenges to the business, for example, targeting "best customers" with the right offer, identifying product bundles, detecting anomalies and potential fraud, finding natural customer segments and gaining customer insight.

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  • How do I express subtle relationships in my data?

    - by Chuck H
    "A" is related to "B" and "C". How do I show that "B" and "C" might, by this context, be related as well? Example: Here are a few headlines about a recent Broadway play: 1 - David Mamet's Glengarry Glen Ross, Starring Al Pacino, Opens on Broadway 2 - Al Pacino in 'Glengarry Glen Ross': What did the critics think? 3 - Al Pacino earns lackluster reviews for Broadway turn 4 - Theater Review: Glengarry Glen Ross Is Selling Its Stars Hard 5 - Glengarry Glen Ross; Hey, Who Killed the Klieg Lights? Problem: Running a fuzzy-string match over these records will establish some relationships, but not others, even though a human reader could pick them out from context in much larger datasets. How do I find the relationship that suggests #3 is related to #4? Both of them can be easily connected to #1, but not to each other. Is there a (Googlable) name for this kind of data or structure? What kind of algorithm am I looking for? Goal: Given 1,000 headlines, a system that automatically suggests that these 5 items are all probably about the same thing. To be honest, it's been so long since I've programmed I'm at a loss how to properly articulate this problem. (I don't know what I don't know, if that makes sense). This is a personal project and I'm writing it in Python. Thanks in advance for any help, advice, and pointers!

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  • Entry / JR Php Programmer - What do I learn next?

    - by dtj
    I got very interested in programming toward the end of college. Took a few classes, but learned most everything on my own via books and such. Its mostly been Php and MySQL. Right out of school, I got a job working at a company for 2 years (web media) and ended up learning a lot of stuff and programming some things for them. I am no longer at that company but I am looking for my next steps as a programmer. I really enjoy Web Development and Php and MySQL seems to be my thing. Basically, I know how to do CRUD operations, i am mediocre at OOP and still have more to learn, I know HTML and CSS quite well, I know my way around a Unix terminal and can access MySQL through it and set up cron jobs and such. I know some basic Javascript. Whats a good next step? I don't anything about 3rd party services, PDO, APIs (twitter, facebook, etc), Drupal / Joomla, Unit Testing, E-Commerce, PECL, PEAR ....in other words A LOT I get easily overwhelmed by the amount of stuff there is to learn, so I'm sort of trying to find a path. Right now, I'm digging into OOP more, as that seems like a good conceptual first-step. Any suggestions?

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  • How to design highly scalable web services in Java?

    - by Kshitiz Sharma
    I am creating some Web Services that would have 2000 concurrent users. The services are offered for free and are hence expected to get a large user base. In the future it may be required to scale up to 50,000 users. There are already a few other questions that address the issue like - Building highly scalable web services However my requirements differ from the question above. For example - My application does not have a user interface, so images, CSS, javascript are not an issue. It is in Java so suggestions like using HipHop to translate PHP to native code are useless. Hence I decided to ask my question separately. This is my project setup - Rest based Web services using Apache CXF Hibernate 3.0 (With relevant optimizations like lazy loading and custom HQL for tune up) Tomcat 6.0 MySql 5.5 My questions are - Are there alternatives to Mysql that offer better performance for what I'm trying to do? What are some general things to abide by in order to scale a Java based web application? I am thinking of putting my Application in two tomcat instances with httpd redirecting the request to appropriate tomcat on basis of load. Is this the right approach? Separate tomcat instances can help but then database becomes the bottleneck since both applications access the same database? I am a programmer not a Db Admin, how difficult would it be to cluster a Mysql database (or, to cluster whatever database offered as an alternative to 1)? How effective are caching solutions like EHCache? Any other general best practices? Some clarifications - Could you partition the data? Yes we could but we're trying to avoid it. We need to run a lot of data mining algorithms and the design would evolve over time so we can't be sure what lines of partition should be there.

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  • What's the proper term for a function inverse to a constructor - to unwrap a value from a data type?

    - by Petr Pudlák
    Edit: I'm rephrasing the question a bit. Apparently I caused some confusion because I didn't realize that the term destructor is used in OOP for something quite different - it's a function invoked when an object is being destroyed. In functional programming we (try to) avoid mutable state so there is no such equivalent to it. (I added the proper tag to the question.) Instead, I've seen that the record field for unwrapping a value (especially for single-valued data types such as newtypes) is sometimes called destructor or perhaps deconstructor. For example, let's have (in Haskell): newtype Wrap = Wrap { unwrap :: Int } Here Wrap is the constructor and unwrap is what? The questions are: How do we call unwrap in functional programming? Deconstructor? Destructor? Or by some other term? And to clarify, is this/other terminology applicable to other functional languages, or is it used just in the Haskell? Perhaps also, is there any terminology for this in general, in non-functional languages? I've seen both terms, for example: ... Most often, one supplies smart constructors and destructors for these to ease working with them. ... at Haskell wiki, or ... The general theme here is to fuse constructor - deconstructor pairs like ... at Haskell wikibook (here it's probably meant in a bit more general sense), or newtype DList a = DL { unDL :: [a] -> [a] } The unDL function is our deconstructor, which removes the DL constructor. ... in The Real World Haskell.

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  • Hidden Gems: Accelerating Oracle Data Integrator with SOA, Groovy, SDK, and XML

    - by Alex Kotopoulis
    On the last day of Oracle OpenWorld, we had a final advanced session on getting the most out of Oracle Data Integrator through the use of various advanced techniques. The primary way to improve your ODI processes is to choose the optimal knowledge modules for your load and take advantage of the optimized tools of your database, such as OracleDataPump and similar mechanisms in other databases. Knowledge modules also allow you to customize tasks, allowing you to codify best practices that are consistently applied by all integration developers. ODI SDK is another very powerful means to automate and speed up your integration development process. This allows you to automate Life Cycle Management, code comparison, repetitive code generation and change of your integration projects. The SDK is easily accessible through Java or scripting languages such as Groovy and Jython. Finally, all Oracle Data Integration products provide services that can be integrated into a larger Service Oriented Architecture. This moved data integration from an isolated environment into an agile part of a larger business process environment. All Oracle data integration products can play a part in thisracle GoldenGate can integrate into business event streams by processing JMS queues or publishing new events based on database transactions. Oracle GoldenGate can integrate into business event streams by processing JMS queues or publishing new events based on database transactions. Oracle Data Integrator allows full control of its runtime sessions through web services, so that integration jobs can become part of business processes. Oracle Data Service Integrator provides a data virtualization layer over your distributed sources, allowing unified reading and updating for heterogeneous data without replicating and moving data. Oracle Enterprise Data Quality provides data quality services to cleanse and deduplicate your records through web services.

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  • LAMP setup - phpmyadmin says the mysqli extension is missing (but its listed in phpinfo)

    - by WebweaverD
    I regularly set up virtualbox ubuntu setups to run as local webservers. I have set these up several times and never had an issue. Recently I have been cloning them but wanted to do a fresh install this time in the hopes of fixing some niggling problems which have propagated through my setups. However, something has changed: 1)vb guest additions no longer allow me to copy and paste (i'll worry about that later) 2)more importantly phpmyadmin no longer works as installed - Initially going to localhost/phpmyadmin gave a message that the page could not be found. So I have followed some instructions (sorry I know its vague I cant find them now) which have created a phpmyadmin directory in /var/www but now I get an error saying: the mysqli extension is missing. If I run phpinfo mysql and mysqli are listed. All I have done so far is install apache2 (working) install php5 (which I think used to come with apache) Install mysql server (and client for good measure) and install phpmyadmin I found a post of a similar question which suggested I should install php5-mysql (done) and edit php.ini and uncomment the line extension-mysqli.so - this is not there, so I tried adding it with no joy. I have restarted apache and still no joy on phpmyadmin. Any help is much appreciated as this is driving me nuts. Why the change for the worse - I was just starting to like linux! I'm running a windows 7 machine and the guest os is ubuntu 12.04 - I ran apt-get update before doing anything so all packages should be the latest versions.

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