multiple columns - Page 332

PHP-FPM and APC for shared hosting?

- by Tiffany Walker

We are looking into finding a way to get APC to only create one cache per account / site. This can be done with Fastcgi (last update 2006…) but with Fastcgid APC will have to create multiple caches for multiple processes run by the same account. To get around this problem, we have been looking into PHP-FPM PHP process manager allows multiple PHP processes to share a single APC cache. But from what I have read (I hope I'm wrong) , even if you create a pool per process, all sites accross all pools will share the same APC cache. This brings us back to the same problem as with shared Memcached: it's not secure ! On php-fpm's site I read that you can chroot php-fpm pools and define a specific UID and GID per pool… if this is the case then shouldn't APC have to use this user and not have access to other pools cache ? An article here (in 2011) suggests that you would need to run one process per pool creating multiple launchers on different ports and different config files with one pool per config file : http://groups.drupal.org/node/198168 Is this still neceessary ? If so what would be the impact of running say 800 processes of php-fpm ? Would it be mainly memory ? If so how can I work out what the memory impact would be ? I guess that it would be better to run 800 times php-fpm then to have accounts creating multiple APC caches for a single site ? If on average an account creates a 50MB cache and creates 3 caches per account that makes 150Mb per account which makes 120GB… However if each account uses on average only 50Mb that would make 40GB We will have at least 128GB of ram on our next server so 40GB is acceptable if running 800 x PHP-FPM does not create an overhead of more than 20GB ! What do you think is PHP-FPM the best way to go to provide secure APC cache on shared hosting with a server that has a decent amount of memory ? Or should I be looking at another system ? Thanks !

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Suggested Web Application Framework and Database for Enterprise, “Big-Data” App?

- by willOEM

I have a web application that I have been developing for a small group within my company over the past few years, using Pipeline Pilot (plus jQuery and Python scripting) for web development and back-end computation, and Oracle 10g for my RDBMS. Users upload experimental genomic data, which is parsed into a database, and made available for querying, transformation, and reporting. Experimental data sets are large and have many layers of metadata. A given experimental data record might have a foreign key relationship with a table that describes this data point's assay. Assays can cover multiple genes, which can have multiple transcript, which can have multiple mutations, which can affect multiple signaling pathways, etc. Users need to approach this data from any point in those layers in the metadata. Since all data sets for a given data type can run over a billion rows, this results in some large, dynamic queries that are hard to predict. New data sets are added on a weekly basis (~1GB per set). Experimental data is never updated, but the associated metadata can be updated weekly for a few records and yearly for most others. For every data set insert the system sees, there will be between 10 and 100 selects run against it and associated data. It is okay for updates and inserts to run slow, so long as queries run quick and are as up-to-date as possible. The application continues to grow in size and scope and is already starting to run slower than I like. I am worried that we have about outgrown Pipeline Pilot, and perhaps Oracle (as the sole database). Would a NoSQL database or an OLAP system be appropriate here? What web application frameworks work well with systems like this? I'd like the solution to be something scalable, portable and supportable X-years down the road. Here is the current state of the application: Web Server/Data Processing: Pipeline Pilot on Windows Server + IIS Database: Oracle 10g, ~1TB of data, ~180 tables with several billion-plus row tables Network Storage: Isilon, ~50TB of low-priority raw data

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July, the 31 Days of SQL Server DMO’s – Day 22 (sys.dm_db_index_physical_stats)

- by Tamarick Hill

The sys.dm_db_index_physical_stats Dynamic Management Function is used to return information about the fragmentation levels, page counts, depth, number of levels, record counts, etc. about the indexes on your database instance. One row is returned for each level in a given index, which we will discuss more later. The function takes a total of 5 input parameters which are (1) database_id, (2) object_id, (3) index_id, (4) partition_number, and (5) the mode of the scan level that you would like to run. Let’s use this function with our AdventureWorks2012 database to better illustrate the information it provides. SELECT * FROM sys.dm_db_index_physical_stats(db_id('AdventureWorks2012'), NULL, NULL, NULL, NULL) As you can see from the result set, there is a lot of beneficial information returned from this DMF. The first couple of columns in the result set (database_id, object_id, index_id, partition_number, index_type_desc, alloc_unit_type_desc) are either self-explanatory or have been explained in our previous blog sessions so I will not go into detail about these at this time. The next column in the result set is the index_depth which represents how deep the index goes. For example, If we have a large index that contains 1 root page, 3 intermediate levels, and 1 leaf level, our index depth would be 5. The next column is the index_level which refers to what level (of the depth) a particular row is referring to. Next is probably one of the most beneficial columns in this result set, which is the avg_fragmentation_in_percent. This column shows you how fragmented a particular level of an index may be. Many people use this column within their index maintenance jobs to dynamically determine whether they should do REORG’s or full REBUILD’s of a given index. The fragment count represents the number of fragments in a leaf level while the avg_fragment_size_in_pages represents the number of pages in a fragment. The page_count column tells you how many pages are in a particular index level. From my result set above, you see the the remaining columns all have NULL values. This is because I did not specify a ‘mode’ in my query and as a result it used the ‘LIMITED’ mode by default. The LIMITED mode is meant to be lightweight so it does collect information for every column in the result set. I will re-run my query again using the ‘DETAILED’ mode and you will see we now have results for these rows. SELECT * FROM sys.dm_db_index_physical_stats(db_id('AdventureWorks2012'), NULL, NULL, NULL, ‘DETAILED’) From the remaining columns, you see we get even more detailed information such as how many records are in a particular index level (record_count). We have a column for ghost_record_count which represents the number of records that have been marked for deletion, but have not physically been removed by the background ghost cleanup process. We later see information on the MIN, MAX, and AVG record size in bytes. The forwarded_record_count column refers to records that have been updated and now no longer fit within the row on the page anymore and thus have to be moved. A forwarded record is left in the original location with a pointer to the new location. The last column in the result set is the compressed_page_count column which tells you how many pages in your index have been compressed. This is a very powerful DMF that returns good information about the current indexes in your system. However, based on the mode you select, it could be a very resource intensive function so be careful with how you use it. For more information on this Dynamic Management Function, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms188917.aspx Follow me on Twitter @PrimeTimeDBA

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ASP.NET MVC: Simple view to display contents of DataTable

- by DigiMortal

In one of my current projects I have to show reports based on SQL Server views. My code should be not aware of data it shows. It just asks data from view and displays it user. As WebGrid didn’t seem to work with DataTable (at least with no hocus-pocus) I wrote my own very simple view that shows contents of DataTable. I don’t focus right now on data querying questions as this part of my simple generic reporting stuff is still under construction. If the final result is something good enough to share with wider audience I will blog about it for sure. My view uses DataTable as model. It iterates through columns collection to get column names and then iterates through rows and writes out values of all columns. Nothing special, just simple generic view for DataTable. @model System.Data.DataTable @using System.Data; <h2>Report</h2> <table> <thead> <tr> @foreach (DataColumn col in Model.Columns) { <th>@col.ColumnName</th> } </tr> </thead> <tbody> @foreach (DataRow row in Model.Rows) { <tr> @foreach (DataColumn col in Model.Columns) { <td>@row[col.ColumnName]</td> } </tr> } </tbody> </table> In my controller action I have code like this. GetParams() is simple function that reads parameter values from form. This part of my simple reporting system is still under construction but as you can see it will be easy to use for UI developers. public ActionResult TasksByProjectReport() { var data = _reportService.GetReportData("MEMOS",GetParams()); return View(data); } Before seeing next silver bullet in this example please calm down. It is just plain and simple stuff for simple needs. If you need advanced and powerful reporting system then better use existing components by some vendor.

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July, the 31 Days of SQL Server DMO’s – Day 19 (sys.dm_exec_query_stats)

- by Tamarick Hill

The sys.dm_exec_query_stats DMV is one of the most useful DMV’s out there when it comes to performance tuning. If you have been keeping up with this blog series this month, you know that I started out on Day 1 reviewing many of the DMV’s within the ‘exec’ namespace. I’m not sure how I missed this one considering how valuable it is, but hey, they say it’s better late than never right?? On Day 7 and Day 8 we reviewed the sys.dm_exec_procedure_stats and sys.dm_exec_trigger_stats respectively. This sys.dm_exec_query_stats DMV is very similar to these two. As a matter of fact, this DMV will return all of the information you saw in the other two DMV’s, but in addition to that, you can see stats for all queries that have cached execution plans on your server. You can even see stats for statements that are ran Ad-Hoc as long as they are still cached in the buffer pool. To better illustrate this DMV, let have a quick look at it: SELECT * FROM sys.dm_exec_query_stats As you can see, there is a lot of information returned from this DMV. I wont go into detail about each and every one of these columns, but I will touch on a few of them briefly. The first column is the ‘sql_handle’, which if you remember from Day 4 of our blog series, I explained how you can use this column to extract the actual SQL text that was executed. The next columns statement_start_offset and statement_end_offset provide you a way of extracting the exact SQL statement that was executed as part of a batch. The plan_handle column is used to extract the Execution plan that was used, which we talked about during Day 5 of this blog series. Later in the result set, you have columns to identify how many times a particular statement was executed, how much CPU time it used, how many reads/writes it performed, the duration, how many rows were returned, etc. These columns provide you with a solid avenue to begin your performance optimization. The last column I will touch on is the query_plan_hash column. A lot of times when you have Dynamic SQL running on your server, you have similar statements with different parameter values being passed in. Many times these types of statements will get similar execution plans and then a Binary hash value can be generated based on these similar plans. This query plan hash can be used to find the cost of all queries that have similar execution plans and then you can tune based on that plan to improve the performance of all of the individual queries. This is a very powerful way of identifying and tuning Ad-hoc statements that run on your server. As I stated earlier, this sys.dm_exec_query_stats DMV is a very powerful and recommended DMV for performance tuning. You are able to quickly identify statements that are running on your server and analyze their impact on system resources. Using this DMV to track down the biggest performance killers on your server will allow you to make the biggest gains once you focus your tuning efforts on those top offenders. For more information about this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms189741.aspx Follow me on Twitter @PrimeTimeDBA

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SQL SERVER – UNION ALL and ORDER BY – How to Order Table Separately While Using UNION ALL

- by pinaldave

I often see developers trying following syntax while using ORDER BY. SELECT Columns FROM TABLE1 ORDER BY Columns UNION ALL SELECT Columns FROM TABLE2 ORDER BY Columns However the above query will return following error. Msg 156, Level 15, State 1, Line 5 Incorrect syntax near the keyword ‘ORDER’. It is not possible to use two different ORDER BY in the UNION statement. UNION returns single resultsetand as per the Logical Query Processing Phases. However, if your requirement is such that you want your top and bottom query of the UNION resultset independently sorted but in the same resultset you can add an additional static column and order by that column. Let us re-create the same scenario. First create two tables and populated with sample data. USE tempdb GO -- Create table CREATE TABLE t1 (ID INT, Col1 VARCHAR(100)); CREATE TABLE t2 (ID INT, Col1 VARCHAR(100)); GO -- Sample Data Build INSERT INTO t1 (ID, Col1) SELECT 1, 'Col1-t1' UNION ALL SELECT 2, 'Col2-t1' UNION ALL SELECT 3, 'Col3-t1'; INSERT INTO t2 (ID, Col1) SELECT 3, 'Col1-t2' UNION ALL SELECT 2, 'Col2-t2' UNION ALL SELECT 1, 'Col3-t2'; GO If we SELECT the data from both the table using UNION ALL . -- SELECT without ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 GO We will get the data in following order. However, our requirement is to get data in following order. If we need data ordered by Column1 we can ORDER the resultset ordered by Column1. -- SELECT with ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 ORDER BY ID GO Now to get the data in independently sorted in UNION ALL let us add additional column OrderKey and use ORDER BY on that column. I think the description does not do proper justice let us see the example here. -- SELECT with ORDER BY - with ORDER KEY SELECT ID, Col1, 'id1' OrderKey FROM t1 UNION ALL SELECT ID, Col1, 'id2' OrderKey FROM t2 ORDER BY OrderKey, ID GO The above query will give the desired result. Now do not forget to clean up the database by running the following script. -- Clean up DROP TABLE t1; DROP TABLE t2; GO Here is the complete script used in this example. USE tempdb GO -- Create table CREATE TABLE t1 (ID INT, Col1 VARCHAR(100)); CREATE TABLE t2 (ID INT, Col1 VARCHAR(100)); GO -- Sample Data Build INSERT INTO t1 (ID, Col1) SELECT 1, 'Col1-t1' UNION ALL SELECT 2, 'Col2-t1' UNION ALL SELECT 3, 'Col3-t1'; INSERT INTO t2 (ID, Col1) SELECT 3, 'Col1-t2' UNION ALL SELECT 2, 'Col2-t2' UNION ALL SELECT 1, 'Col3-t2'; GO -- SELECT without ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 GO -- SELECT with ORDER BY SELECT ID, Col1 FROM t1 UNION ALL SELECT ID, Col1 FROM t2 ORDER BY ID GO -- SELECT with ORDER BY - with ORDER KEY SELECT ID, Col1, 'id1' OrderKey FROM t1 UNION ALL SELECT ID, Col1, 'id2' OrderKey FROM t2 ORDER BY OrderKey, ID GO -- Clean up DROP TABLE t1; DROP TABLE t2; GO I am sure there are many more ways to achieve this, what method would you use if you have to face the similar situation? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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Organizations & Architecture UNISA Studies – Chap 7

- by MarkPearl

Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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Best Way to Archive Digital Photos and Avoid Duplicate File Names

- by user31575

This problem pertains to archiving of digital pictures taken from multiple cameras. Answers here covered the general topic of the-mechanics-of-backups: How do you archive digital photos and videos ? I however face another problem. Having multiple cameras (canon) and multiple SD cards (mixed and matched at random), I have found that different SD cards have different photos with the same file name, i.e. two different photos each name IMG_3141.JPG. Additionally, for better or worse, I've backed up the files to multiple places and need to consolidate my backups. I want to eliminate duplicates, but not clobber files. The only way I can think of is to append the code (md5 or sha1) to the file name, i.e. IMG_3141.JPG becomes IMG_3141_KT229QZ31415926ASDF.JPG, then sorting them out Any better ways? (Note "open letter" address the 'duplicate file name' concern): http://photofocus.com/2010/09/13/an-open-letter-to-digital-camera-manufacturers-regarding-camera-file-naming/ )

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Farseer: Cutting body from texture

- by Robin Betka

Is it possible to cut a body from a texture in Farseer 3.0? I have a texture converted to a body with multiple fixtures ( using BayazitDecomposer, CreatePolygon method, ..) and can even do it as a BreakableBody. But when I try to cut it with the cutting tool, the fixture itself gets cutted but it's connections get discarded! So when I have 14 fixtures, and cut fixture 3 for example, fixture 3 gets cutted but 1,2 and 3-14 just go away. Is there a way to do it? It would work already if I could convert the texture into a body with 1 fixture only, but I haven't figured out it that's possible. BayazitDecomposer creates the multiple verticles, but letting it away creates something weird and I get assert messages all the time. I know I couldn't break it that way but I don't need that anyway when I could cut it. The breaking is just the work around I'm using now. Extending the cuttingtool to support multiple fixtures is very hard especially when you consider that in one cut multiple fixtures could be cutted and then connected again.

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More Tables or More Databases?

- by BuckWoody

I got an e-mail from someone that has an interesting situation. He has 15,000 customers, and he asks if he should have a database for their data per customer. Without a LOT more data it’s impossible to say, of course, but there are some general concepts to keep in mind. Whenever you’re segmenting data, it’s all about boundary choices. You have not only boundaries around how big the data will get, but things like how many objects (tables, stored procedures and so on) that will be involved, if there are any cross-sections of data (do they share location or product information) and – very important – what are the security requirements? From the answer to these types of questions, you now have the choice of making multiple tables in a single database, or using multiple databases. A database carries some overhead – it needs a certain amount of memory for locking and so on. But it has a very clean boundary – everything from objects to security can be kept apart. Having multiple users in the same database is possible as well, using things like a Schema. But keeping 15,000 schemas can be challenging as well. My recommendation in complex situations like this is similar to a post on decisions that I did earlier – I lay out the choices on a spreadsheet in rows, and then my requirements at the top in the columns. I give each choice a number based on how well it meets each requirement. At the end, the highest number wins. And many times it’s a mix – perhaps this person could segment customers into larger regions or districts or products, in a database. Within that database might be multiple schemas for the customers. Of course, he needs to query across all customers, that becomes another requirement. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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Creating Tables in DokuWiki

- by Bryan

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question about dns

- by manohara

how to add multiple domainnames in named.conf file for both forward and reverse lookup zones

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Creating Tables in DocuWiki

- by Bryan

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More Tables or More Databases?

- by BuckWoody

I got an e-mail from someone that has an interesting situation. He has 15,000 customers, and he asks if he should have a database for their data per customer. Without a LOT more data it’s impossible to say, of course, but there are some general concepts to keep in mind. Whenever you’re segmenting data, it’s all about boundary choices. You have not only boundaries around how big the data will get, but things like how many objects (tables, stored procedures and so on) that will be involved, if there are any cross-sections of data (do they share location or product information) and – very important – what are the security requirements? From the answer to these types of questions, you now have the choice of making multiple tables in a single database, or using multiple databases. A database carries some overhead – it needs a certain amount of memory for locking and so on. But it has a very clean boundary – everything from objects to security can be kept apart. Having multiple users in the same database is possible as well, using things like a Schema. But keeping 15,000 schemas can be challenging as well. My recommendation in complex situations like this is similar to a post on decisions that I did earlier – I lay out the choices on a spreadsheet in rows, and then my requirements at the top in the columns. I give each choice a number based on how well it meets each requirement. At the end, the highest number wins. And many times it’s a mix – perhaps this person could segment customers into larger regions or districts or products, in a database. Within that database might be multiple schemas for the customers. Of course, he needs to query across all customers, that becomes another requirement. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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Program that groups windows into tabs

- by Arithmomaniac

I recall once stumbling on a program that could take multiple application windows and wrap them inside a large window with a tabbed interface. One use of this, for example, would be to wrap multiple instances of Excel into one window, and thus icon on the taskbar. I couldn't find mention of this program via Google, because of the multiple meanings of the word "window". Does anyone remember, or know of, such a program?

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Limit IE8 to a single window (always use tabs)

- by compie

How can I prevent Internet Explorer 8 from opening multiple windows? I only want a single IE window, with multiple tabs. Sometimes a have multiple browser windows open and I don't like it when I have to choose which one I want to open in the Windows 7 taskbar.

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Scene or Activity Animation

- by Siddharth

My game require an animation when one activity finishes and next started because I have develop game with multiple activity not as multiple scene per game. I have to show animation at the time of activity creation and activity destroy. I have trying to create basic animation that was supported by android. And all that xml file I have to post it into the anim folder but the loading of resource was so much high so any type of animation I provide using android method does not work for me it look weird. If scene class has some functionality for animation that please know me then I try to load different type of animation using scene. I have not create multiple scene because I have no awareness about how to manage multiple scene in andengine though I have a working experience of 8 months in andengine. So this help also provide me a great help. Basically I want to create animation like one activity slide out at the same time the other activity slide in. So at a time user can see the transition of activity. Thanks in advance.

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Silverlight nested RadGridView SelectedItem DataContext

- by Ciaran

Hi, I'm developing a Silverlight 4 app and am using the 2010 Q1 release 1 RadGridView. I'm developing this app using the MVVM pattern and trying to keep my codebehind to a minimum. On my View I have a RadGridView and this binds to a property on my ViewModel. I am setting a property via the SelectedItem. I have a nested RadGridView and I want to set a property on my ViewModel to the SelectedItem but I cannot. I think the DataContext of my nested grid is the element in the parent's bound collection, rather than my ViewModel. I can easily use codebehind to set my ViewModel property from the SelectionChanged event on the nested grid, but I'd rather not do this. I have tried to use my viewModelName in the ElementName in my nested grid to specify that for SelectedItem, the ViewModel is the DataContext, but I cannot get this to work. Any ideas? Here is my Xaml: <grid:RadGridView x:Name="master" ItemsSource="{Binding EntityClassList, Mode=TwoWay}" SelectedItem="{Binding SelectedEntityClass, Mode=TwoWay}" AutoGenerateColumns="False" > <grid:RadGridView.Columns> <grid:GridViewSelectColumn></grid:GridViewSelectColumn> <grid:GridViewDataColumn DataMemberBinding="{Binding Description}" Header="Description"/. </grid:RadGridView.Columns> <grid:RadGridView.RowDetailsTemplate> <DataTemplate> <grid:RadGridView x:Name="child" ItemsSource="{Binding EntityDetails, Mode=TwoWay}" SelectedItem="{Binding DataContext.SelectedEntityDetail, ElementName='RequestView', Mode=TwoWay}" AutoGenerateColumns="False" > <grid:RadGridView.Columns> <grid:GridViewSelectColumn></grid:GridViewSelectColumn> <grid:GridViewDataColumn DataMemberBinding="{Binding ServiceItem}" Header="Service Item" /> <grid:GridViewDataColumn DataMemberBinding="{Binding Comment}" Header="Comments" /> </grid:RadGridView.Columns> </grid:RadGridView> </DataTemplate> </grid:RadGridView.RowDetailsTemplate> </grid:RadGridView>

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Datapager in silverlight 4 -Nested datagrid visibility issue

- by Archie

I have a datagrid in silverlight with child datagrid nested in it. Also I have a DataPager on the outer datagrid. The code looks like this: <data:DataGrid x:Name="dgData" Width="600" ItemsSource="{Binding}" AutoGenerateColumns="False" IsReadOnly="True" HorizontalScrollBarVisibility="Hidden" CanUserSortColumns="False" RowDetailsVisibilityChanged="dgData_RowDetailsVisibilityChanged" Margin="20,0" Grid.RowSpan="2"> <data:DataGrid.Columns> <data:DataGridTextColumn Header="Item" Width="*" Binding="{Binding ItemName,Mode=TwoWay}"/> <data:DataGridTextColumn Header="Company" Width="*" Binding="{Binding Company,Mode=TwoWay}"/> </data:DataGrid.Columns> <data:DataGrid.RowDetailsTemplate> <DataTemplate> <data:DataGrid x:Name="dgRowDetail" Width="400" HorizontalScrollBarVisibility="Hidden" AutoGenerateColumns="False" Visibility="Collapsed"> <data:DataGrid.Columns> <data:DataGridTextColumn Header="Date" Width="*" Binding="{Binding Date,Mode=TwoWay}"/> <data:DataGridTextColumn Header="Price" Width="*" Binding="{Binding Price,Mode=TwoWay}"/> </data:DataGrid.Columns> </data:DataGrid> </DataTemplate> </data:DataGrid.RowDetailsTemplate> </data:DataGrid> <data:DataPager x:Name="dpData" HorizontalAlignment="Center" DisplayMode="FirstLastPreviousNextNumeric" Source="{Binding}"/> I have one PagedCollectionView pgv which is bound to outer datagrid as: DataContext = pgv; When the row is clicked I set the child datagrid's ItemsSource property to another PagedCollectionView. My problem is it works fine except for the first row for the first time. When I click on it, it doesn't fire the dgData_RowDetailsVisibilityChanged event. Also, when I click on second row, firstly first row fires the event and then the second row fires it and shows the nested grid. Please help.

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Pass data to Child Window in Silverlight 4 using MVVM

- by Archie

Hello, I have a datagrid with master detail implementation as follows: <data:DataGrid x:Name="dgData" Width="600" ItemsSource="{Binding Path=ItemCollection}" HorizontalScrollBarVisibility="Hidden" CanUserSortColumns="False" RowDetailsVisibilityChanged="dgData_RowDetailsVisibilityChanged"> <data:DataGrid.Columns> <data:DataGridTextColumn Header="Item" Width="*" Binding="{Binding Item,Mode=TwoWay}"/> <data:DataGridTextColumn Header="Company" Width="*" Binding="{Binding Company,Mode=TwoWay}"/> </data:DataGrid.Columns> <data:DataGrid.RowDetailsTemplate> <DataTemplate> <data:DataGrid x:Name="dgrdRowDetail" Width="400" AutoGenerateColumns="False" HorizontalAlignment="Center" HorizontalScrollBarVisibility="Hidden" Grid.Row="1"> <data:DataGrid.Columns> <data:DataGridTextColumn Header="Date" Width="*" Binding="{Binding Date,Mode=TwoWay}"/> <data:DataGridTextColumn Header="Price" Width="*" Binding="{Binding Price, Mode=TwoWay}"/> <data:DataGridTemplateColumn> <data:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Button Content="Show More Details" Click="buttonShowDetail_Click"></Button> </DataTemplate> </data:DataGridTemplateColumn.CellTemplate> </data:DataGridTemplateColumn> </data:DataGrid.Columns> </data:DataGrid> </DataTemplate> </data:DataGrid.RowDetailsTemplate> </data:DataGrid> I want to open a Child window in clicking the button which shows more details about the product. I'm using MVVM pattern. My Model contains a method which takes the Item name as input and retursn the Details data. My problem is how should I pass the Item to ViewModel which will get the Details data from Model? and where shoukd I open the new Child Window? In View or ViewModel? Please help.Thanks.

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RadGrid nestedview sort makes nestedview disappear?

- by lance

When I click on the header of my detail table, it disappears entirely, leaving empty white space in the browser where it used to be. The Ajax postback caused by my clicking on the header does fire FooGridNeedDataSource and FooGridItemCommand, but I've used the debugger to skip the code inside those handlers (after clicking the header of the column I'm trying to sort, in the detail table), and I still get the same behavior. I'm hoping someone can tell me what I'm doing wrong? The MasterTableView sorts just fine (my real markup enables that with AllowSorting="true" on MasterTableView). <telerik:RadGrid ID="FooGrid" runat="server" AutoGenerateColumns="false" OnNeedDataSource="FooGridNeedDataSource" OnItemCommand="FooGridItemCommand" > <MasterTableView ClientDataKeyNames="FooData" DataKeyNames="FooData"> <Columns> <telerik:GridBoundColumn DataField="FooData" HeaderText="Foo"></telerik:GridBoundColumn> </Columns> <DetailTables> <telerik:GridTableView AllowSorting="true"> <Columns> <telerik:GridBoundColumn DataField="FooDetailData" HeaderText="Foo Detail" ></telerik:GridBoundColumn> </Columns> </telerik:GridTableView> </DetailTables> </MasterTableView> </telerik:RadGrid>

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Why does Adding Core Animation slow down drawing of my NSTableView?

- by Will Goring

I have a simple App that displays a list of items using NSTableView. There are usually about 15-25 items in the list, and the table has 10 columns, all but one of which are text (the other's an icon.) There are simple data transformers on a couple of the columns. So nothing taxing; you'd expect it to run just fine. And as it stands, it is; the app is responsive and everything draws pretty much instantly. Scrolling, changing column sizes, resizing the window; whatever you do the redraws keep up with the mouse-pointer. Tonight, I thought I'd try adding a little visual flair to the app with Core Animation (which I've never used before,) but I've found that if anything above the NSTableView in the hierarchy is set 'Wants Core Animation Layer,' then the NSTableView redraws go to hell. Scrolling is usually fine, but resizing columns or the window causes it to pick up an effect like texture tearing, where some of the rows have the new size, and some have the old one, and everything flickers horribly. It looks terrible. Basically it looks like what you'd expect if rendering the individual rows or columns was taking a long time. I've put it through Shark and, sure enough, it looks like it's spending most of its time drawing the text in the cells; what I don't understand is why that should take longer when there's a Core Animation layer involved than when there isn't - and quite noticeably longer at that. Has anyone got any ideas? Is there any Core Animation initialisation or config I've missed or something (I've literally just ticked the "Wants Core Animation Layer" box in IB)? Cheers, Will

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How to list column headers of a SQL Server table using sp_help perhaps?

- by Hamish Grubijan

Hi, I have a few tables with 70-80 columns in them. I would like to populate them with somewhat random data, unless I will not be able to do so due to key violation, etc. The first step would be simply to get the list of all headers. There seem to be two ways: A) Run select * from table_of_interest; in MSFT SQL Server Management Studio 2008. Now, right-click the result and click "Copy With headers". However, I get zero rows back, and when I try to copy nothing + headers, I get: TITLE: Microsoft SQL Server Management Studio ------------------------------ Value cannot be null. Parameter name: data (System.Windows.Forms) ------------------------------ BUTTONS: OK ------------------------------ This looks like a bug ... anyhow ... there is another way. B) I can run sp_help table_of_interest;. However, I end up getting too much back. I get 7 different tables back but I am only interested in the second one. The columns of the second table are: Column_name | Type | Computed | Length | Prec | Scale | Nullable | TrimTrailingBlanks | FixedLenNullInSource | Collation I might be interested in just a Column_name and Type, but maybe other columns. So ... since sp_help probably runs a bunch of queries ... how do I get under the hood? How can I run the second query AND filter down the number of columns that I am interested in? Many Thanks!

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expand an collapse button in datagrid

- by prince23

hi, <sdk:DataGrid MinHeight="100" x:Name="dgCounty" AutoGenerateColumns="False" VerticalAlignment="Top" IsReadOnly="True" Margin="5,5,5,0" RowDetailsVisibilityChanged="dgCounty_RowDetailsVisibilityChanged" RowDetailsVisibilityMode="VisibleWhenSelected"> <sdk:DataGrid.Columns> <sdk:DataGridTemplateColumn CanUserReorder="False"> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Button x:Name="ViewButton" Click="ToggleRowDetailsVisibility" Cursor="Hand" Content="View Details" /> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> <sdk:DataGridTextColumn Header="Countryname" Width="100" Binding="{Binding Region Name}" CanUserReorder="False"/> <sdk:DataGridTextColumn Header="Populution" Width="80" Binding="{Binding Number Of People}" CanUserReorder="False"/> </sdk:DataGrid.Columns> <sdk:DataGrid.RowDetailsTemplate> <DataTemplate> <sdk:DataGrid x:Name="dgrdRowDetail" Width="400" AutoGenerateColumns="False" HorizontalAlignment="Center" IsReadOnly="True" Grid.Row="1"> <sdk:DataGrid.Columns> <sdk:DataGridTextColumn Header="county" Binding="{Binding CompanyName}"/> <sdk:DataGridTextColumn Header="Number Of People" Binding="{Binding CompanyID}"/> </sdk:DataGrid.Columns> </sdk:DataGrid> </DataTemplate> </sdk:DataGrid.RowDetailsTemplate> </sdk:DataGrid> how to make an button in datagrid expand an collapse where there will be 2 image buttons once user clicks the button the rows under it will expand where there should be an one image button with (- symbol) again user clicks the same row the rows which were expanded should collapse.(+ image button) here i have done the function for doing the expand and collapse is completed. now only i need add an image which will change once the user clicks the row either ( we can do it by javascript or in code behind ?) how can i change the image button like that can any one tell me how i should i ahead or any code that can help me to solve the issue thanks in adance prince

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fill combobox value in datagridview based on other combobox in datagridview

- by Purohit Raghu

I m creating Web Application..in C# I have One Data grid view In that i Have 2 Combo box i m trying 2 bind second combo box based on first combo-box. in First Combo-box I have value Shirt,T shirt so i want if shirt is selected than second combo-box should have value Slim,Regular..and if T shirt Is selected than second Combo-box should have V neck and rounded color. i have different table for thirst and shirt type... I work fine for first time but when i goes on second row and change the combo box value than it will also change value of second combo box value of previous row as well .. Where i need to change to prevent change in upper row i have following code private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { if (dataGridView1.CurrentCell.ColumnIndex == 0) { ComboBox cbx = e.Control as ComboBox; cbx.SelectionChangeCommitted -= new EventHandler(cbx_SelectionChangeCommitted); cbx.SelectionChangeCommitted += new EventHandler(cbx_SelectionChangeCommitted); } } private void cbx_SelectionChangeCommitted(object sender, EventArgs e) { int selectedIndex = ((ComboBox)sender).SelectedIndex; if (selectedIndex == 1) //this condition is true if i have selected shirt from combobox1 { ShirtType(); } if (selectedIndex == 2) { Tshirtype(); } } void ShirtType() { try { string str; str = "select ShirtType_name,ShirtType_Id from ShirtType_master"; ds = new DataSet(); ds = cn.readdata(str); Type.DataSource = ds.Tables[0];//Type is Combobox name of Second Combobox Type.DisplayMember = ds.Tables[0].Columns[0].ToString(); ; Type.ValueMember = ds.Tables[0].Columns[1].ToString(); ; } catch (Exception ee) { } } void Tshirtype() { try { string str; str = "select TShirtType_name,TshirtType_Id from TshirtType_Master"; ds = new DataSet(); ds = cn.readdata(str); Type.DataSource = ds.Tables[0]; Type.DisplayMember = ds.Tables[0].Columns[0].ToString(); ; Type.ValueMember = ds.Tables[0].Columns[1].ToString(); ; }

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