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  • Does anyone have database, programming language/framework suggestions for a GUI point of sale system

    - by Jason Down
    Our company has a point of sale system with many extras, such as ordering and receiving functionality, sales and order history etc. Our main issue is that the system was not designed properly from the ground up, so it takes too long to make fixes and handle requests from our customers. Also, the current technology we are using (Progress database, Progress 4GL for the language) incurs quite a bit of licensing expenses on our customers due to mutli-user license fees for database connections etc. After a lot of discussion it is looking like we will probably start over from scratch (while maintaining the current product at least for the time being). We are looking for a couple of things: Create the system with a nice GUI front end (it is currently CHUI and the application was not built in a way that allows us to redesign the front end... no layering or separation of business logic and gui...shudder). Create the system with the ability to modularize different functionality so the product doesn't have to include all features. This would keep the cost down for our current customers that want basic functionality and a lower price tag. The bells and whistles would be available for those that would want them. Use proper design patterns to make the product easy to add or change any part at any time (i.e. change the database or change the front end without needing to rewrite the application or most of it). This is a problem today because the Progress 4GL code is directly compiled against the database. Small changes in the database requires lots of code recompiling. Our new system will be Linux based, with a possibility of a client application providing functionality from one or more windows boxes. So what I'm looking for is any suggestions on which database and/or framework or programming language(s) someone might recommend for this sort of product. Anyone that has experience in this field might be able to point us in the right direction or even have some ideas of what to avoid. We have considered .NET and SQL Express (we don't need an enterprise level DB), but that would limit us to windows (as far as I know anyway). I have heard of Mono for writing .NET code in a Linux environment, but I don't know much about it yet. We've also considered a Java and MySql based implementation. To summarize we are looking to do the following: Keep licensing costs down on the technology we will use to develop the product (Oracle, yikes! MySQL, nice.) Deliver a solution that is easily maintainable and supportable. A solution that has a component capable of running on "old" hardware through a CHUI front end. (some of our customers have 40+ terminals which would be a ton of cash in order to convert over to a PC). Suggestions would be appreciated. Thanks [UPDATE] I should note that we are currently performing a total cost analysis. This question is intended to give us a couple of "educated" options to look into to include in or analysis. Anyone who could share experiences/suggestions about client/server setups would be appreciated (not just those who have experience with point of sale systems... that would just be a bonus).

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  • What is the correct term for - server/client database sync via API?

    - by Daniel
    Forgive the vague question title. I've been programming mobile apps for 3 years now, and I've got a little too far from the web services and server side code then I probably should have. Anyway, I'm doing a personal project now and I want to create an web API for it. One of my requirements is to check for updates from my app, so I would send a timestamp to the API. I've used many APIs that my clients prepared for me and only now am I appreciating their work ! What is the term or technique used to create an API backed by a database which tracks changes via dates/timestamps, basically an effective way for me to query changes occurring since a timestamp. Simply put, I want that my app can call my API in order to sync new data and changed data from the server, to the app. The app would only have a timestamp of the last time it synced with the server. Would I have a log table for each data table in my database which adds a record for each change? Then I could query all changes with a timestamp superior to the one passed to the API. Can anyone point me in the right direction on this?

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  • How to install Oracle Database 11g Express Edition on Ubuntu 12.10?

    - by Praneeth Pj
    I installed the Oracle database following the steps mentioned in this blog. Downloaded 11g express edition Created a new user oracle under the group dba. Following steps are executed using this. Unzipped oracle-xe-11.2.0-1.0.x86_64.rpm.zip and then converted the rpm to the Ubuntu package by running: sudo alien --scripts -d oracle-xe-11.2.0-1.0.x86_64.rpm Created /sbin/chkconfig file and added the entries as specified there. Created /etc/sysctl.d/60-oracle.conf and added the entries as specified in the same link as above. Running the commands: ln -s /usr/bin/awk /bin/awk mkdir /var/lock/subsys touch /var/lock/subsys/listener .deb generated in step 3: sudo dpkg --install oracle-xe_11.2.0-2_amd64.deb Left the default values as it is: sudo /etc/init.d/oracle-xe configure Set the following env variables in ~/.bashrc file: export ORACLE_HOME=/u01/app/oracle/product/11.2.0/xe export ORACLE_SID=XE export NLS_LANG=`$ORACLE_HOME/bin/nls_lang.sh` export ORACLE_BASE=/u01/app/oracle export LD_LIBRARY_PATH=$ORACLE_HOME/lib:$LD_LIBRARY_PATH export PATH=$ORACLE_HOME/bin:$PATH Running the commands: chown -R oracle:dba /var/tmp/.oracle chmod -R 755 /var/tmp/.oracle chown -R oracle:dba /tmp/.oracle chmod -R 755 /tmp/.oracle Starting Oracle Database 11g Express Edition instance: sudo service oracle-xe start sqlplus / as sysdba and got the following: SQL*Plus: Release 11.2.0.2.0 Production on Thu Jan 3 09:41:58 2013 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to an idle instance. Now when exectuting any SQL statements on SQLplus, I end up with the following error: SQL> select * from dual; select * from dual * ERROR at line 1: ORA-01034: ORACLE not available Process ID: 0 Session ID: 0 Serial number: 0 I have increased the swap memory as specified here $ free -m total used free shared buffers cached Mem: 3901 3428 473 0 182 1988 -/+ buffers/cache: 1258 2643 Swap: 5066 0 5066

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  • How to use function to connect to database and how to work with queries?

    - by Abhilash Shukla
    I am using functions to work with database.. Now the way i have defined the functions are as follows:- /** * Database definations */ define ('db_type', 'MYSQL'); define ('db_host', 'localhost'); define ('db_port', '3306'); define ('db_name', 'database'); define ('db_user', 'root'); define ('db_pass', 'password'); define ('db_table_prefix', ''); /** * Database Connect */ function db_connect($host = db_host, $port = db_port, $username = db_user, $password = db_pass, $database = db_name) { if(!$db = @mysql_connect($host.':'.$port, $username, $password)) { return FALSE; } if((strlen($database) > 0) AND (!@mysql_select_db($database, $db))) { return FALSE; } // set the correct charset encoding mysql_query('SET NAMES \'utf8\''); mysql_query('SET CHARACTER_SET \'utf8\''); return $db; } /** * Database Close */ function db_close($identifier) { return mysql_close($identifier); } /** * Database Query */ function db_query($query, $identifier) { return mysql_query($query, $identifier); } Now i want to know whether it is a good way to do this or not..... Also, while database connect i am using $host = db_host Is it ok? Secondly how i can use these functions, these all code is in my FUNCTIONS.php The Database Definitions and also the Database Connect... will it do the needful for me... Using these functions how will i be able to connect to database and using the query function... how will i able to execute a query? VERY IMPORTANT: How can i make mysql to mysqli, is it can be done by just adding an 'i' to mysql....Like:- @mysql_connect @mysqli_connect

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  • What is the best approach for database design with lots of columns?

    - by Pratyush
    I am writing a query based financial application. It lets the user to write complicated equations (much like WHERE part of an SQL query) and find companies matching those criteria. For the above, I currently have more than 500 columns in the database table (each column representing a financial field). Example of Columns are: company_name, sales_annual_00, sales_annual_01, sales_annual_02, sales_annual_03, sales_annual_04, protit_annual_00, profit_annual1...(over 500 such columns). The number of rows is around 5000. Going forward, I would like to further increase the number of columns/financial-fields. For the above I would like to get help regarding: 1) What is the best database design approach? Is it ok to have these many number of columns? 2) How can it be normalized? (User can use any of these fields in search criteria). 3) Is it ok to stick with MySQL, or modern document based databases like MongoDB should be better for it? P.S. (Update): I have been using MySQL till now and a running example of the usage is at: http://screener.in/companies/89/Formula-- In above there around 500 fields/columns to create your query on, however, I seek to increase that number to much more in future.

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  • Unable to edit a database row from JSF

    - by user1924104
    Hi guys i have a data table in JSF which displays all of the contents of my database table, it displays it fine, i also have a delete function that can successfully delete from the database fine and updates the data table fine however when i try to update the database i get the error java.lang.IllegalArgumentException: Cannot convert richard.test.User@129d62a7 of type class richard.test.User to long below is the code that i have been using to delete the rows in the database that is working fine : public void delete(long userID) { PreparedStatement ps = null; Connection con = null; if (userID != 0) { try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root"); String sql = "DELETE FROM user1 WHERE userId=" + userID; ps = con.prepareStatement(sql); int i = ps.executeUpdate(); if (i > 0) { System.out.println("Row deleted successfully"); } } catch (Exception e) { e.printStackTrace(); } finally { try { con.close(); ps.close(); } catch (Exception e) { e.printStackTrace(); } } } } i simply wanted to edit the above code so it would update the records instead of deleting them so i edited it to look like : public void editData(long userID) { PreparedStatement ps = null; Connection con = null; if (userID != 0) { try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "root"); String sql = "UPDATE user1 set name = '"+name+"', email = '"+ email +"', address = '"+address+"' WHERE userId=" + userID; ps = con.prepareStatement(sql); int i = ps.executeUpdate(); if (i > 0) { System.out.println("Row updated successfully"); } } catch (Exception e) { e.printStackTrace(); } finally { try { con.close(); ps.close(); } catch (Exception e) { e.printStackTrace(); } } } } and the xhmtl is : <p:dataTable id="dataTable" var="u" value="#{userBean.getUserList()}" paginator="true" rows="10" editable="true" paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}" rowsPerPageTemplate="5,10,15"> <p:column> <f:facet name="header"> User ID </f:facet> #{u.userID} </p:column> <p:column> <f:facet name="header"> Name </f:facet> #{u.name} </p:column> <p:column> <f:facet name="header"> Email </f:facet> #{u.email} </p:column> <p:column> <f:facet name="header"> Address </f:facet> #{u.address} </p:column> <p:column> <f:facet name="header"> Created Date </f:facet> #{u.created_date} </p:column> <p:column> <f:facet name="header"> Delete </f:facet> <h:commandButton value="Delete" action="#{user.delete(u.userID)}" /> </p:column> <p:column> <f:facet name="header"> Delete </f:facet> <h:commandButton value="Edit" action="#{user.editData(u)}" /> </p:column> currently when you press the edit button it will only update it with the same values as i haven't yet managed to get the datatable to be editable with the database, i have seen a few examples with an array list where the data table gets its values from but never a database so if you have any advice on this too it would be great thanks

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  • Should I use a config file or database for storing business rules?

    - by foiseworth
    I have recently been reading The Pragmatic Programmer which states that: Details mess up our pristine code—especially if they change frequently. Every time we have to go in and change the code to accommodate some change in business logic, or in the law, or in management's personal tastes of the day, we run the risk of breaking the system—of introducing a new bug. Hunt, Andrew; Thomas, David (1999-10-20). The Pragmatic Programmer: From Journeyman to Master (Kindle Locations 2651-2653). Pearson Education (USA). Kindle Edition. I am currently programming a web app that has some models that have properties that can only be from a set of values, e.g. (not actual example as the web app data confidential): light-type = sphere / cube / cylinder The light type can only be the above three values but according to TPP I should always code as if they could change and place their values in a config file. As there are several incidents of this throughout the app, my question is: Should I store possibly values like these in: a config file: 'light-types' = array(sphere, cube, cylinder), 'other-type' = value, 'etc = etc-value a single table in a database with one line for each config item a database with a table for each config item (e.g. table: light_types; columns: id, name) some other way? Many thanks for any assistance / expertise offered.

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  • How do I develop database-utilizing application in an agile/test-driven-development way?

    - by user39019
    I want to add databases (traditional client/server RDBMS's like Mysql/Postgresql as opposed to NoSQL, or embedded databases) to my toolbox as a developer. I've been using SQLite for simpler projects with only 1 client, but now I want to do more complicated things (ie, db-backed web development). I usually like following agile and/or test-driven-development principles. I generally code in Perl or Python. Questions: How do I test my code such that each run of the test suite starts with a 'pristine' state? Do I run a separate instance of the database server every test? Do I use a temporary database? How do I design my tables/schema so that it is flexible with respect to changing requirements? Do I start with an ORM for my language? Or do I stick to manually coding SQL? One thing I don't find appealing is having to change more than one thing (say, the CREATE TABLE statement and associated crud statements) for one change, b/c that's error prone. On the other hand, I expect ORM's to be a low slower and harder to debug than raw SQL. What is the general strategy for migrating data between one version of the program and a newer one? Do I carefully write ALTER TABLE statements between each version, or do I dump the data and import fresh in the new version?

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  • Keeping files or database records? Java and Python

    - by danpalmer
    My website will use a Neural Network to predict thing based on user data. The user can select the data to be used in training the network and then use their trained network to predict things. I am using a framework to create, train and query the networks. This uses Java. The framework has persistence for saving a network to an XML file. What is the best way to store these files? I can see several potential ideas, but I need help on choosing which is best: Save each network to a separate XML file with a name that is stored in the database. Load this each time. Save all the networks to the same XML file with each network having a different name that is stored in the database. Somehow pass what would normally be written to an XML file to the Django site for writing to the database. This would need to be returned to the Java code when a prediction needs to be made. I am able to do 1 or 2, but I think their performance will be quite limited and I am on shared hosting at the moment, so I don't know how pleased they would be with thousands of files. Also, after adding a few thousand records to one XML file, I was noticing a massive performance hit on saving to it. If I were able to implement version 3 somehow I think it would be best. No issues with separate processes accessing the database and I think performance would be better. Not to mention having no files lying around. However, the stuff in the neural network framework I am using (Encog) for saving to a file needs access to a Java file object, not a string that could be saved to a database. Unless there is some Java magic I can do here (I know very little Java), the only way I can see of doing this would be with a temporary files but I don't know if this is the correct way to do it. I would appreciate any ideas on the best way to implement any of the above 3 ideas or any alternatives. Thanks!

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  • Preview hidden options on web sites

    - by veili_13
    I want to have hidden options on my web site and be previewed only when the user chooses. I want to animate them from left and right (about 15%). At the moment I have them visible in my html but with width set at 0 and animate it at 15%. In these containers are many options which should disappear to the left/right (with slide effect). But I am not so sure that having all of this in my HTML so I am thinking to create them with jQuery, with 0 width and animating it to it's should be width and setting the other elements to 0 width. Is this approach good, or should I create them and hide the overflow so I would animate position. Or is there a better approach ??

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  • How to Easily Add Custom Right-Click Options to Ubuntu’s File Manager

    - by Chris Hoffman
    Use Nautilus-Actions to easily and graphically create custom context menu options for Ubuntu’s Nautilus file manager. If you don’t want to create your own, you can install Nautilus-Actions-Extra to get a package of particularly useful user-created tools. Nautilus-Actions is simple to use – much simpler than editing the Windows registry to add Windows Explorer context menu options. All you really have to do is name your option and specify a command or script to run. HTG Explains: What Is Windows RT and What Does It Mean To Me? HTG Explains: How Windows 8′s Secure Boot Feature Works & What It Means for Linux Hack Your Kindle for Easy Font Customization

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  • Option Trading: Getting the most out of the event session options

    - by extended_events
    You can control different aspects of how an event session behaves by setting the event session options as part of the CREATE EVENT SESSION DDL. The default settings for the event session options are designed to handle most of the common event collection situations so I generally recommend that you just use the defaults. Like everything in the real world though, there are going to be a handful of “special cases” that require something different. This post focuses on identifying the special cases and the correct use of the options to accommodate those cases. There is a reason it’s called Default The default session options specify a total event buffer size of 4 MB with a 30 second latency. Translating this into human terms; this means that our default behavior is that the system will start processing events from the event buffer when we reach about 1.3 MB of events or after 30 seconds, which ever comes first. Aside: What’s up with the 1.3 MB, I thought you said the buffer was 4 MB?The Extended Events engine takes the total buffer size specified by MAX_MEMORY (4MB by default) and divides it into 3 equally sized buffers. This is done so that a session can be publishing events to one buffer while other buffers are being processed. There are always at least three buffers; how to get more than three is covered later. Using this configuration, the Extended Events engine can “keep up” with most event sessions on standard workloads. Why is this? The fact is that most events are small, really small; on the order of a couple hundred bytes. Even when you start considering events that carry dynamically sized data (eg. binary, text, etc.) or adding actions that collect additional data, the total size of the event is still likely to be pretty small. This means that each buffer can likely hold thousands of events before it has to be processed. When the event buffers are finally processed there is an economy of scale achieved since most targets support bulk processing of the events so they are processed at the buffer level rather than the individual event level. When all this is working together it’s more likely that a full buffer will be processed and put back into the ready queue before the remaining buffers (remember, there are at least three) are full. I know what you’re going to say: “My server is exceptional! My workload is so massive it defies categorization!” OK, maybe you weren’t going to say that exactly, but you were probably thinking it. The point is that there are situations that won’t be covered by the Default, but that’s a good place to start and this post assumes you’ve started there so that you have something to look at in order to determine if you do have a special case that needs different settings. So let’s get to the special cases… What event just fired?! How about now?! Now?! If you believe the commercial adage from Heinz Ketchup (Heinz Slow Good Ketchup ad on You Tube), some things are worth the wait. This is not a belief held by most DBAs, particularly DBAs who are looking for an answer to a troubleshooting question fast. If you’re one of these anxious DBAs, or maybe just a Program Manager doing a demo, then 30 seconds might be longer than you’re comfortable waiting. If you find yourself in this situation then consider changing the MAX_DISPATCH_LATENCY option for your event session. This option will force the event buffers to be processed based on your time schedule. This option only makes sense for the asynchronous targets since those are the ones where we allow events to build up in the event buffer – if you’re using one of the synchronous targets this option isn’t relevant. Avoid forgotten events by increasing your memory Have you ever had one of those days where you keep forgetting things? That can happen in Extended Events too; we call it dropped events. In order to optimizes for server performance and help ensure that the Extended Events doesn’t block the server if to drop events that can’t be published to a buffer because the buffer is full. You can determine if events are being dropped from a session by querying the dm_xe_sessions DMV and looking at the dropped_event_count field. Aside: Should you care if you’re dropping events?Maybe not – think about why you’re collecting data in the first place and whether you’re really going to miss a few dropped events. For example, if you’re collecting query duration stats over thousands of executions of a query it won’t make a huge difference to miss a couple executions. Use your best judgment. If you find that your session is dropping events it means that the event buffer is not large enough to handle the volume of events that are being published. There are two ways to address this problem. First, you could collect fewer events – examine you session to see if you are over collecting. Do you need all the actions you’ve specified? Could you apply a predicate to be more specific about when you fire the event? Assuming the session is defined correctly, the next option is to change the MAX_MEMORY option to a larger number. Picking the right event buffer size might take some trial and error, but a good place to start is with the number of dropped events compared to the number you’ve collected. Aside: There are three different behaviors for dropping events that you specify using the EVENT_RETENTION_MODE option. The default is to allow single event loss and you should stick with this setting since it is the best choice for keeping the impact on server performance low.You’ll be tempted to use the setting to not lose any events (NO_EVENT_LOSS) – resist this urge since it can result in blocking on the server. If you’re worried that you’re losing events you should be increasing your event buffer memory as described in this section. Some events are too big to fail A less common reason for dropping an event is when an event is so large that it can’t fit into the event buffer. Even though most events are going to be small, you might find a condition that occasionally generates a very large event. You can determine if your session is dropping large events by looking at the dm_xe_sessions DMV once again, this time check the largest_event_dropped_size. If this value is larger than the size of your event buffer [remember, the size of your event buffer, by default, is max_memory / 3] then you need a large event buffer. To specify a large event buffer you set the MAX_EVENT_SIZE option to a value large enough to fit the largest event dropped based on data from the DMV. When you set this option the Extended Events engine will create two buffers of this size to accommodate these large events. As an added bonus (no extra charge) the large event buffer will also be used to store normal events in the cases where the normal event buffers are all full and waiting to be processed. (Note: This is just a side-effect, not the intended use. If you’re dropping many normal events then you should increase your normal event buffer size.) Partitioning: moving your events to a sub-division Earlier I alluded to the fact that you can configure your event session to use more than the standard three event buffers – this is called partitioning and is controlled by the MEMORY_PARTITION_MODE option. The result of setting this option is fairly easy to explain, but knowing when to use it is a bit more art than science. First the science… You can configure partitioning in three ways: None, Per NUMA Node & Per CPU. This specifies the location where sets of event buffers are created with fairly obvious implication. There are rules we follow for sub-dividing the total memory (specified by MAX_MEMORY) between all the event buffers that are specific to the mode used: None: 3 buffers (fixed)Node: 3 * number_of_nodesCPU: 2.5 * number_of_cpus Here are some examples of what this means for different Node/CPU counts: Configuration None Node CPU 2 CPUs, 1 Node 3 buffers 3 buffers 5 buffers 6 CPUs, 2 Node 3 buffers 6 buffers 15 buffers 40 CPUs, 5 Nodes 3 buffers 15 buffers 100 buffers   Aside: Buffer size on multi-processor computersAs the number of Nodes or CPUs increases, the size of the event buffer gets smaller because the total memory is sub-divided into more pieces. The defaults will hold up to this for a while since each buffer set is holding events only from the Node or CPU that it is associated with, but at some point the buffers will get too small and you’ll either see events being dropped or you’ll get an error when you create your session because you’re below the minimum buffer size. Increase the MAX_MEMORY setting to an appropriate number for the configuration. The most likely reason to start partitioning is going to be related to performance. If you notice that running an event session is impacting the performance of your server beyond a reasonably expected level [Yes, there is a reasonably expected level of work required to collect events.] then partitioning might be an answer. Before you partition you might want to check a few other things: Is your event retention set to NO_EVENT_LOSS and causing blocking? (I told you not to do this.) Consider changing your event loss mode or increasing memory. Are you over collecting and causing more work than necessary? Consider adding predicates to events or removing unnecessary events and actions from your session. Are you writing the file target to the same slow disk that you use for TempDB and your other high activity databases? <kidding> <not really> It’s always worth considering the end to end picture – if you’re writing events to a file you can be impacted by I/O, network; all the usual stuff. Assuming you’ve ruled out the obvious (and not so obvious) issues, there are performance conditions that will be addressed by partitioning. For example, it’s possible to have a successful event session (eg. no dropped events) but still see a performance impact because you have many CPUs all attempting to write to the same free buffer and having to wait in line to finish their work. This is a case where partitioning would relieve the contention between the different CPUs and likely reduce the performance impact cause by the event session. There is no DMV you can check to find these conditions – sorry – that’s where the art comes in. This is  largely a matter of experimentation. On the bright side you probably won’t need to to worry about this level of detail all that often. The performance impact of Extended Events is significantly lower than what you may be used to with SQL Trace. You will likely only care about the impact if you are trying to set up a long running event session that will be part of your everyday workload – sessions used for short term troubleshooting will likely fall into the “reasonably expected impact” category. Hey buddy – I think you forgot something OK, there are two options I didn’t cover: STARTUP_STATE & TRACK_CAUSALITY. If you want your event sessions to start automatically when the server starts, set the STARTUP_STATE option to ON. (Now there is only one option I didn’t cover.) I’m going to leave causality for another post since it’s not really related to session behavior, it’s more about event analysis. - Mike Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Option Trading: Getting the most out of the event session options

    - by extended_events
    You can control different aspects of how an event session behaves by setting the event session options as part of the CREATE EVENT SESSION DDL. The default settings for the event session options are designed to handle most of the common event collection situations so I generally recommend that you just use the defaults. Like everything in the real world though, there are going to be a handful of “special cases” that require something different. This post focuses on identifying the special cases and the correct use of the options to accommodate those cases. There is a reason it’s called Default The default session options specify a total event buffer size of 4 MB with a 30 second latency. Translating this into human terms; this means that our default behavior is that the system will start processing events from the event buffer when we reach about 1.3 MB of events or after 30 seconds, which ever comes first. Aside: What’s up with the 1.3 MB, I thought you said the buffer was 4 MB?The Extended Events engine takes the total buffer size specified by MAX_MEMORY (4MB by default) and divides it into 3 equally sized buffers. This is done so that a session can be publishing events to one buffer while other buffers are being processed. There are always at least three buffers; how to get more than three is covered later. Using this configuration, the Extended Events engine can “keep up” with most event sessions on standard workloads. Why is this? The fact is that most events are small, really small; on the order of a couple hundred bytes. Even when you start considering events that carry dynamically sized data (eg. binary, text, etc.) or adding actions that collect additional data, the total size of the event is still likely to be pretty small. This means that each buffer can likely hold thousands of events before it has to be processed. When the event buffers are finally processed there is an economy of scale achieved since most targets support bulk processing of the events so they are processed at the buffer level rather than the individual event level. When all this is working together it’s more likely that a full buffer will be processed and put back into the ready queue before the remaining buffers (remember, there are at least three) are full. I know what you’re going to say: “My server is exceptional! My workload is so massive it defies categorization!” OK, maybe you weren’t going to say that exactly, but you were probably thinking it. The point is that there are situations that won’t be covered by the Default, but that’s a good place to start and this post assumes you’ve started there so that you have something to look at in order to determine if you do have a special case that needs different settings. So let’s get to the special cases… What event just fired?! How about now?! Now?! If you believe the commercial adage from Heinz Ketchup (Heinz Slow Good Ketchup ad on You Tube), some things are worth the wait. This is not a belief held by most DBAs, particularly DBAs who are looking for an answer to a troubleshooting question fast. If you’re one of these anxious DBAs, or maybe just a Program Manager doing a demo, then 30 seconds might be longer than you’re comfortable waiting. If you find yourself in this situation then consider changing the MAX_DISPATCH_LATENCY option for your event session. This option will force the event buffers to be processed based on your time schedule. This option only makes sense for the asynchronous targets since those are the ones where we allow events to build up in the event buffer – if you’re using one of the synchronous targets this option isn’t relevant. Avoid forgotten events by increasing your memory Have you ever had one of those days where you keep forgetting things? That can happen in Extended Events too; we call it dropped events. In order to optimizes for server performance and help ensure that the Extended Events doesn’t block the server if to drop events that can’t be published to a buffer because the buffer is full. You can determine if events are being dropped from a session by querying the dm_xe_sessions DMV and looking at the dropped_event_count field. Aside: Should you care if you’re dropping events?Maybe not – think about why you’re collecting data in the first place and whether you’re really going to miss a few dropped events. For example, if you’re collecting query duration stats over thousands of executions of a query it won’t make a huge difference to miss a couple executions. Use your best judgment. If you find that your session is dropping events it means that the event buffer is not large enough to handle the volume of events that are being published. There are two ways to address this problem. First, you could collect fewer events – examine you session to see if you are over collecting. Do you need all the actions you’ve specified? Could you apply a predicate to be more specific about when you fire the event? Assuming the session is defined correctly, the next option is to change the MAX_MEMORY option to a larger number. Picking the right event buffer size might take some trial and error, but a good place to start is with the number of dropped events compared to the number you’ve collected. Aside: There are three different behaviors for dropping events that you specify using the EVENT_RETENTION_MODE option. The default is to allow single event loss and you should stick with this setting since it is the best choice for keeping the impact on server performance low.You’ll be tempted to use the setting to not lose any events (NO_EVENT_LOSS) – resist this urge since it can result in blocking on the server. If you’re worried that you’re losing events you should be increasing your event buffer memory as described in this section. Some events are too big to fail A less common reason for dropping an event is when an event is so large that it can’t fit into the event buffer. Even though most events are going to be small, you might find a condition that occasionally generates a very large event. You can determine if your session is dropping large events by looking at the dm_xe_sessions DMV once again, this time check the largest_event_dropped_size. If this value is larger than the size of your event buffer [remember, the size of your event buffer, by default, is max_memory / 3] then you need a large event buffer. To specify a large event buffer you set the MAX_EVENT_SIZE option to a value large enough to fit the largest event dropped based on data from the DMV. When you set this option the Extended Events engine will create two buffers of this size to accommodate these large events. As an added bonus (no extra charge) the large event buffer will also be used to store normal events in the cases where the normal event buffers are all full and waiting to be processed. (Note: This is just a side-effect, not the intended use. If you’re dropping many normal events then you should increase your normal event buffer size.) Partitioning: moving your events to a sub-division Earlier I alluded to the fact that you can configure your event session to use more than the standard three event buffers – this is called partitioning and is controlled by the MEMORY_PARTITION_MODE option. The result of setting this option is fairly easy to explain, but knowing when to use it is a bit more art than science. First the science… You can configure partitioning in three ways: None, Per NUMA Node & Per CPU. This specifies the location where sets of event buffers are created with fairly obvious implication. There are rules we follow for sub-dividing the total memory (specified by MAX_MEMORY) between all the event buffers that are specific to the mode used: None: 3 buffers (fixed)Node: 3 * number_of_nodesCPU: 2.5 * number_of_cpus Here are some examples of what this means for different Node/CPU counts: Configuration None Node CPU 2 CPUs, 1 Node 3 buffers 3 buffers 5 buffers 6 CPUs, 2 Node 3 buffers 6 buffers 15 buffers 40 CPUs, 5 Nodes 3 buffers 15 buffers 100 buffers   Aside: Buffer size on multi-processor computersAs the number of Nodes or CPUs increases, the size of the event buffer gets smaller because the total memory is sub-divided into more pieces. The defaults will hold up to this for a while since each buffer set is holding events only from the Node or CPU that it is associated with, but at some point the buffers will get too small and you’ll either see events being dropped or you’ll get an error when you create your session because you’re below the minimum buffer size. Increase the MAX_MEMORY setting to an appropriate number for the configuration. The most likely reason to start partitioning is going to be related to performance. If you notice that running an event session is impacting the performance of your server beyond a reasonably expected level [Yes, there is a reasonably expected level of work required to collect events.] then partitioning might be an answer. Before you partition you might want to check a few other things: Is your event retention set to NO_EVENT_LOSS and causing blocking? (I told you not to do this.) Consider changing your event loss mode or increasing memory. Are you over collecting and causing more work than necessary? Consider adding predicates to events or removing unnecessary events and actions from your session. Are you writing the file target to the same slow disk that you use for TempDB and your other high activity databases? <kidding> <not really> It’s always worth considering the end to end picture – if you’re writing events to a file you can be impacted by I/O, network; all the usual stuff. Assuming you’ve ruled out the obvious (and not so obvious) issues, there are performance conditions that will be addressed by partitioning. For example, it’s possible to have a successful event session (eg. no dropped events) but still see a performance impact because you have many CPUs all attempting to write to the same free buffer and having to wait in line to finish their work. This is a case where partitioning would relieve the contention between the different CPUs and likely reduce the performance impact cause by the event session. There is no DMV you can check to find these conditions – sorry – that’s where the art comes in. This is  largely a matter of experimentation. On the bright side you probably won’t need to to worry about this level of detail all that often. The performance impact of Extended Events is significantly lower than what you may be used to with SQL Trace. You will likely only care about the impact if you are trying to set up a long running event session that will be part of your everyday workload – sessions used for short term troubleshooting will likely fall into the “reasonably expected impact” category. Hey buddy – I think you forgot something OK, there are two options I didn’t cover: STARTUP_STATE & TRACK_CAUSALITY. If you want your event sessions to start automatically when the server starts, set the STARTUP_STATE option to ON. (Now there is only one option I didn’t cover.) I’m going to leave causality for another post since it’s not really related to session behavior, it’s more about event analysis. - Mike Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • Magento Checkout options

    - by graham barnes
    Hi I want to add some options to my magento, lets say i print on clothing, a customer buys some t-shirts, shirts and jackets from me, it totals to £60+ VAT on the checkout area where i signup and not before I need to add an option where I can add a text box and upload option, can i do this? I ideally then want to add some pricing options if the user has chosen to add some branding to a product or multiple products e.g. if the branding was on the top right of the shirt it will cost £5.00, if on the back it costs £7.00 etc all if possible to be done via the admincp. I also want an option so when they upload their logo for the first time they are charged a one off charge, like a setup fee but If the customer has allready sent in there logo then no charge applies. thanks Graham

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  • Magento Checkout options

    - by graham barnes
    Hi I want to add some options to my magento, lets say i print on clothing, a customer buys some t-shirts, shirts and jackets from me, it totals to £60+ VAT on the checkout area where i signup and not before I need to add an option where I can add a text box and upload option, can i do this? I ideally then want to add some pricing options if the user has chosen to add some branding to a product or multiple products e.g. if the branding was on the top right of the shirt it will cost £5.00, if on the back it costs £7.00 etc all if possible to be done via the admincp. I also want an option so when they upload their logo for the first time they are charged a one off charge, like a setup fee but If the customer has allready sent in there logo then no charge applies. thanks Graham

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  • Joomla and Google Analytics advanced options in tracking code

    - by miako
    I want to insert google analytics tracking code in my joomla site. so i registered in the official site of google and saw there is an advanced tab with three more options than standard. Do i have to check "i want to track dynamic pages" and "i want to track php pages"? Do these options provide me better results or they are necessary for a dynamic site based on php like joomla? Does anyone know the process of installing? because i didn't manage to make it work by following this Also where do i place the tracking code? Because of some bugs some say it is better just after the tag <body> whereas other say just before the tag </body>. Thank you

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  • Where did all of the options go? [closed]

    - by Devan
    In the last version of Ubuntu I used (10.04) I had the following options, which I can not find on 11.10: Set amount of time before screen dims Show percent instead of time in battery icon Change/add screensaver Change default applications (especially in the new launcher) Also, is there any way to make it so unity opens to more apps/all instead of the current default? Basically I just need to know if there's any way to customize Ubuntu that little bit more. Any help with any of the options above would be greatly appreciated! Note: I'm a noob and don't know much about command line, so gui apps would be preferred, if possible.

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  • No options for sound output

    - by Chef Flambe
    Newbie here. Trying out Ubuntu for kicks. I have a 10.04 Ubuntu system dual booting on my Windows 7 laptop, fully updated, an Asus A53S. I have an external Samsung monitor/tv hooked up via HDMI. I'm getting sound from the external monitor fine when using Win7 but can't get anything with Ubuntu. I've read threads here about similar stuff and they say go check my sound options but I don't have any additional options than the one listed - Internal Audio. What else can I check/do?

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  • ???????:“Upgrade to Oracle Database 12c”

    - by hamsun
    ? ?:Brandye Barrington,2014?4?29? ??????????????“Upgrade to Oracle Database 12c”,??Oracle????(OCM ) ??????????Gwen Lazenby??????12??????????43?????,Gwen Lazenby? ?????Oracle???? 1Z0-060???????????, ? ?????????????????????,????????? ???????????????,? ?????? ?????????:Upgrade to Oracle Database 12c? ??????????????????????????Kaplan SelfTest? ???? ??????? ????:Upgrade to Oracle Database 12c, ???? ?????????:Upgrade to Oracle Database 12c? ?????????????????????????????Kaplan SelfTest? ???? ? ?????????????: ??0:???? ?? 1:?????????????? ?? 2:?????CDB?PDB ?? 3: ??CDB?PDB ?? 4:???????????????????????(?CDB/PDB? ?? 5:?CDB/PDB????????? ? ?? 6:??????????? ?? 7:??Unicode?EM Express? ???? ?? 8:????????????? ?? 9:????????????? ?? 10: ?? ?? 11:????????? ?? 12: ?? ?? 13:?????????????? ?? 14: Oracle Database 12c??RMAN? ??? ?? 15: ??????? ?? 16:ADR???? ?? 17:Oracle Database 12c?????? ?? 18:?? Oracle? ???? ?? 19: ??Oracle Database 12c  ?? 20:??Oracle? ??? ?? 21: ??????? ?? 22: ???? ?? 23: ???? ?? 24: ?????? ?? 25: ?????? ?? 26: ?? ?? 27: ?? ?? 28: ??????? ?? 29: ? ??????????? ?? 30: ??????? ?? 31: ?????? ?? 32: ???????? ?? 33:??RMAN? ???????? ?? 34: ??RMAN???? ?? 35: ???? ?? 36: ?????? ?? 37: ?????? ?? 38: ???????? ?? 39: ???? ?? 40: ?????? ?? 41:??SQL ? ?????? ?? 42:?????Direct NFS ?? 43:??Oracle Data Pump? ??? ????????Oracle Database Administrator Certified Professional?????Oracle Database 12c,????????????????,???????????,????????????????,?????????? ????,?????????????????? ? ??? ?????: Certification Exam Prep Seminar: Upgrade to Oracle Database 12c ??????????: Exam Prep Seminar Value Package: Upgrade to Oracle Database 12c ????: 1Z0-060 Upgrade to 12c - New Features of Oracle Database 12c ????:Oracle Database 12c Administrator Certified Professional

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  • How to give an error when no options are given with optparse

    - by Acorn
    I'm try to work out how to use optparse, but I've come to a problem. My script (represented by this simplified example) takes a file, and does different things to it depending on options that are parsed to it. If no options are parsed nothing is done. It makes sense to me that because of this, an error should be given if no options are given by the user. I can't work out how to do this. Am I using options in the wrong way? If so, how should I be doing it instead? #!/usr/bin/python from optparse import OptionParser dict = {'name': foo, 'age': bar} parser = OptionParser() parser.add_option("-n", "--name", dest="name") parser.add_option("-a", "--age", dest="age") (options, args) = parser.parse_args() if options.name: dict['name'] = options.name if options.age: dict['age'] = options.age print dict #END

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  • Copy Selective Data from Database to Invoice, Based on Certain Criteria

    - by Scott
    For starters, here is an example of a microsoft excel database I am working with: Month/Address/Name/Description/Amount January/123 Street/Fred/Painting/100 January/456 Avenue/Scott/Flooring/400 January/789 Road/Scott/Plumbing/100 February/123 Street/Fred/Flooring/600 February/246 Lane/Fred/Electrical/300 March/789 Road/Scott/Drywall/150 What I want to be able to do is selectively copy info from this databse to invoices (also excel). The invoice has three columns: Address/Description/Amount. I want to be able to automatically fill the invoices in as the database is filled in (either automatically, or if I have to actually manually run the macro to do it, that might be fine). Each name (Scott, Fred, etc.) will have their own set of 12 invoices for the year. So, e.g., I want to be able to produce a January invoice for all work done for Scott in January, showing the address, the description and the amount, line by line. So every time work on Scott's address(es) is done, the database is filled in, and i want it to "send" that information to the invoice on the next available line, filling in only the Address/Description/Amount columns from the database. Fred's invoice should fill in as any work is done on Fred's addresses. And once the month changes, the next invoice should start filling in. So first I need to filter the data by the month and the name (and there is actually one more column to filter by, but let's keep this example simpler). Then I need to list the remaining data on the invoice, but only certain cells from the rows that are now left. Help anyone?

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  • Creating an AJAX Searchable Database.

    - by Austin
    Currently I am using MySQLi to parse a CSV file into a Database, that step has been accomplished. However, My next step would be to make this Database searchable and automatically updated via jQuery.ajax(). Some people suggest that I print out the Database in another page and access it externally. I'm quite new to jquery + ajax so if anyone could point me in the right direction that would be greatly appreciated. I understand that the documentation on ajax should be enough to tell me what I'm looking for but it appears to talk only about retrieving data from an external file, what about from a mysql database? The code so far stands: <head> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script> </head> <body> <input type="text" id="search" name="search" /> <input type="submit" value="submit"> <?php show_source(__FILE__); error_reporting(E_ALL);ini_set('display_errors', '1'); $category = NULL; $mc = new Memcache; $mc->addServer('localhost','11211'); $sql = new mysqli('localhost', 'user', 'pword', 'db'); $cache = $mc->get("updated_DB"); $query = 'SELECT cat,name,web,kw FROM infoDB WHERE cat LIKE ? OR name LIKE ? OR web LIKE ? OR kw LIKE ?'; $results = $sql->prepare($query); $results->bind_param('ssss', $query, $query, $query, $query); $results->execute(); $results->store_result(); ?> </body> </html>

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  • Database migration pattern for Java?

    - by Eno
    Im working on some database migration code in Java. Im also using a factory pattern so I can use different kinds of databases. And each kind of database im using implements a common interface. What I would like to do is have a migration check that is internal to the class and runs some database schema update code automatically. The actual update is pretty straight forward (I check schema version in a table and compare against a constant in my app to decide whether to migrate or not and between which versions of schema). To make this automatic I was thinking the test should live inside (or be called from) the constructor. OK, fair enough, that's simple enough. My problem is that I dont want the test to run every single time I instantiate a database object (it runs a query so having it run on every construction is not efficient). So maybe this should be a class static method? I guess my question is, what is a good design pattern for this type of problem? There ought to be a clean way to ensure the migration test runs only once OR is super-efficient.

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  • Database design for sharing photos site?

    - by javaLearner.java
    I am using php and mysql. If I want to do a sharing photos website, whats the best database design for upload and display photos. This is what I have in mind: domain: |_> photos |_> user Logged in user will upload photo in [http://www.domain.com/user/upload.php] The photos are stored in filesystems, and the path-to-photos stored in database. So, in my photos folder would be like: photos/userA/subfolders+photos, photos/userB/subfolders+photos, photos/userC/subfolders+photos etc Public/others people may view his photo in: [http://www.domain.com/photos/user/?photoid=123] where 123 is the photoid, from there, I will query from database to fetch the path and display the image. My questions: Whats the best database design for photo-sharing website (like flickr)? Will there be any problems if I keep creating new folder in "photos" folder. What if hundreds of thousands users registered? Whats the best practices What size of photos should I keep? Currently I only stored thumbnail (100x100) and (max) 1600x1200 px photos. What others things I should take note when developing photos-sharing website?

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