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  • How do I track down sporadic ASP.NET performance problems in a production environment?

    - by Steve Wortham
    I've had sporadic performance problems with my website for awhile now. 90% of the time the site is very fast. But occasionally it is just really, really slow. I mean like 5-10 seconds load time kind of slow. I thought I had narrowed it down to the server I was on so I migrated everything to a new dedicated server from a completely different web hosting company. But the problems continue. I guess what I'm looking for is a good tool that'll help me track down the problem, because it's clearly not the hardware. I'd like to be able to log certain events in my ASP.NET code and have that same logger also track server performance/resources at the time. If I can then look back at the logs then I can see what exactly my website was doing at the time of extreme slowness. Is there a .NET logging system that'll allow me to make calls into it with code while simultaneously tracking performance? What would you recommend?

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  • How do I improve my performance with this singly linked list struct within my program?

    - by Jesus
    Hey guys, I have a program that does operations of sets of strings. We have to implement functions such as addition and subtraction of two sets of strings. We are suppose to get it down to the point where performance if of O(N+M), where N,M are sets of strings. Right now, I believe my performance is at O(N*M), since I for each element of N, I go through every element of M. I'm particularly focused on getting the subtraction to the proper performance, as if I can get that down to proper performance, I believe I can carry that knowledge over to the rest of things I have to implement. The '-' operator is suppose to work like this, for example. Declare set1 to be an empty set. Declare set2 to be a set with { a b c } elements Declare set3 to be a set with ( b c d } elements set1 = set2 - set3 And now set1 is suppose to equal { a }. So basically, just remove any element from set3, that is also in set2. For the addition implementation (overloaded '+' operator), I also do the sorting of the strings (since we have to). All the functions work right now btw. So I was wondering if anyone could a) Confirm that currently I'm doing O(N*M) performance b) Give me some ideas/implementations on how to improve the performance to O(N+M) Note: I cannot add any member variables or functions to the class strSet or to the node structure. The implementation of the main program isn't very important, but I will post the code for my class definition and the implementation of the member functions: strSet2.h (Implementation of my class and struct) // Class to implement sets of strings // Implements operators for union, intersection, subtraction, // etc. for sets of strings // V1.1 15 Feb 2011 Added guard (#ifndef), deleted using namespace RCH #ifndef _STRSET_ #define _STRSET_ #include <iostream> #include <vector> #include <string> // Deleted: using namespace std; 15 Feb 2011 RCH struct node { std::string s1; node * next; }; class strSet { private: node * first; public: strSet (); // Create empty set strSet (std::string s); // Create singleton set strSet (const strSet &copy); // Copy constructor ~strSet (); // Destructor int SIZE() const; bool isMember (std::string s) const; strSet operator + (const strSet& rtSide); // Union strSet operator - (const strSet& rtSide); // Set subtraction strSet& operator = (const strSet& rtSide); // Assignment }; // End of strSet class #endif // _STRSET_ strSet2.cpp (implementation of member functions) #include <iostream> #include <vector> #include <string> #include "strset2.h" using namespace std; strSet::strSet() { first = NULL; } strSet::strSet(string s) { node *temp; temp = new node; temp->s1 = s; temp->next = NULL; first = temp; } strSet::strSet(const strSet& copy) { if(copy.first == NULL) { first = NULL; } else { node *n = copy.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } } strSet::~strSet() { if(first != NULL) { while(first->next != NULL) { node *nextNode = first->next; first->next = nextNode->next; delete nextNode; } } } int strSet::SIZE() const { int size = 0; node *temp = first; while(temp!=NULL) { size++; temp=temp->next; } return size; } bool strSet::isMember(string s) const { node *temp = first; while(temp != NULL) { if(temp->s1 == s) { return true; } temp = temp->next; } return false; } strSet strSet::operator + (const strSet& rtSide) { strSet newSet; newSet = *this; node *temp = rtSide.first; while(temp != NULL) { string newEle = temp->s1; if(!isMember(newEle)) { if(newSet.first==NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; newSet.first = newNode; } else if(newSet.SIZE() == 1) { if(newEle < newSet.first->s1) { node *tempNext = newSet.first; node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = tempNext; newSet.first = newNode; } else { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; newSet.first->next = newNode; } } else { node *prev = NULL; node *curr = newSet.first; while(curr != NULL) { if(newEle < curr->s1) { if(prev == NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = curr; newSet.first = newNode; break; } else { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = curr; prev->next = newNode; break; } } if(curr->next == NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; curr->next = newNode; break; } prev = curr; curr = curr->next; } } } temp = temp->next; } return newSet; } strSet strSet::operator - (const strSet& rtSide) { strSet newSet; newSet = *this; node *temp = rtSide.first; while(temp != NULL) { string element = temp->s1; node *prev = NULL; node *curr = newSet.first; while(curr != NULL) { if( element < curr->s1 ) break; if( curr->s1 == element ) { if( prev == NULL) { node *duplicate = curr; newSet.first = newSet.first->next; delete duplicate; break; } else { node *duplicate = curr; prev->next = curr->next; delete duplicate; break; } } prev = curr; curr = curr->next; } temp = temp->next; } return newSet; } strSet& strSet::operator = (const strSet& rtSide) { if(this != &rtSide) { if(first != NULL) { while(first->next != NULL) { node *nextNode = first->next; first->next = nextNode->next; delete nextNode; } } if(rtSide.first == NULL) { first = NULL; } else { node *n = rtSide.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } } return *this; }

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  • The best way to predict performance without actually porting the code?

    - by ardiyu07
    I believe there are people with the same experience with me, where he/she must give a (estimated) performance report of porting a program from sequential to parallel with some designated multicore hardwares, with a very few amount of time given. For instance, if a 10K LoC sequential program was given and executes on Intel i7-3770k (not vectorized) in 100 ms, how long would it take to run if one parallelizes the code to a Tesla C2075 with NVIDIA CUDA, given that all kinds of parallelizing optimization techniques were done? (but you're only given 2-4 days to report the performance? assume that you didn't know the algorithm at all. Or perhaps it'd be safer if we just assume that it's an impossible situation to finish the job) Therefore, I'm wondering, what most likely be the fastest way to give such performance report? Is it safe to calculate solely by the hardware's capability, such as GFLOPs peak and memory bandwidth rate? Is there a mathematical way to calculate it? If there is, please prove your method with the corresponding problem description and the algorithm, and also the target hardwares' specifications. Or perhaps there already exists such tool to (roughly) estimate code porting? (Please don't the answer: 'kill yourself is the fastest way.')

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  • SQL SERVER – Subquery or Join – Various Options – SQL Server Engine knows the Best

    - by pinaldave
    This is followup post of my earlier article SQL SERVER – Convert IN to EXISTS – Performance Talk, after reading all the comments I have received I felt that I could write more on the same subject to clear few things out. First let us run following four queries, all of them are giving exactly same resultset. USE AdventureWorks GO -- use of = SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID = ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- use of in SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID IN ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- use of exists SELECT * FROM HumanResources.Employee E WHERE EXISTS ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- Use of Join SELECT * FROM HumanResources.Employee E INNER JOIN HumanResources.EmployeeAddress EA ON E.EmployeeID = EA.EmployeeID GO Let us compare the execution plan of the queries listed above. Click on image to see larger image. It is quite clear from the execution plan that in case of IN, EXISTS and JOIN SQL Server Engines is smart enough to figure out what is the best optimal plan of Merge Join for the same query and execute the same. However, in the case of use of Equal (=) Operator, SQL Server is forced to use Nested Loop and test each result of the inner query and compare to outer query, leading to cut the performance. Please note that here I no mean suggesting that Nested Loop is bad or Merge Join is better. This can very well vary on your machine and amount of resources available on your computer. When I see Equal (=) operator used in query like above, I usually recommend to see if user can use IN or EXISTS or JOIN. As I said, this can very much vary on different system. What is your take in above query? I believe SQL Server Engines is usually pretty smart to figure out what is ideal execution plan and use it. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Server Side Paging in SQL Server 2011 – Part2

    - by pinaldave
    The best part of the having blog is that SQL Community helps to keep it running with new ideas. Earlier I wrote about SQL SERVER – Server Side Paging in SQL Server 2011 – A Better Alternative. A very popular article on that subject. I had used variables for “number of the rows” and “number of the pages”. Blog reader send me email asking in their organizations these values are stored in the table. Is there any the new syntax can read the data from the table. Absolutely YES! USE AdventureWorks2008R2 GO CREATE TABLE PagingSetting (RowsPerPage INT, PageNumber INT) INSERT INTO PagingSetting (RowsPerPage, PageNumber) VALUES(10,5) GO SELECT * FROM Sales.SalesOrderDetail ORDER BY SalesOrderDetailID OFFSET (SELECT RowsPerPage*PageNumber FROM PagingSetting) ROWS FETCH NEXT (SELECT RowsPerPage FROM PagingSetting) ROWS ONLY GO Here is the quick script: This is really an easy trick. I also wrote blog post on comparison of the performance over here: . SQL SERVER – Server Side Paging in SQL Server 2011 Performance Comparison Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology Tagged: SQL Paging

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  • SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – SQL and 10-11 May SharePoint

    - by pinaldave
    There were lots of request about providing more details for the blog post through email address specified in the article SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning. Here is the complete brochure of the course. There are two different courses are offered by Solid Quality Mentors 1) Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning – Pinal Dave Date: May 12-14, 2010 Price: Rs. 14,000/person for 3 days Discount Code: ‘SQLAuthority.com‘ Effective Price: Rs. 11,000/person for 3 days 2) SharePoint 2010 – Joy Rathnayake Date: May 10-11, 2010 Price: Rs. 11,000/person for 3 days Discount Code: ‘SQLAuthority.com’ Effective Price: Rs. 8,000/person for 3 days Download the complete PDF brochure. Additionally there is special program of SolidQ India Insider. I will provide the details for the same very soon. Please do send me email if you need any additional details. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Technology

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  • Oracle Linux Delivers Top CPU Benchmark Results on Sun Blades

    - by sergio.leunissen
    From the Performance and Best Practices blog: Fresh SPEC CPU2006 results for Sun Blade X6275 M2 Server Modules running Oracle Linux 5.5. The highlights: The dual-node Sun Blade X6275 M2 server module, equipped with two Intel Xeon X5670 2.93 GHz processors per node and running the Oracle Enterprise Linux 5.5 operating system delivered the best SPECint_rate2006 and SPECfp_rate2006 benchmark results for all systems with Intel Xeon processor 5000 sequence. With a SPECint_rate2006 benchmark result of 679, the Sun Blade X6275 M2 server module, with two compute nodes per blade, delivers maximum performance for space constrained environments. Comparing Oracle's dual-node blade to HP's dual-node blade server, based on their single node performance, the Sun Blade X6275 M2 server module SPECfp_rate2006 score of 241 outperforms the best published HP ProLiant BL2X220c G5 server score by 3.2x. A single node of a Sun Blade X6275 M2 server module using 2.93 GHz Intel Xeon X5670 processors delivered 37% improvement in SPECint_rate2006 benchmark results and 22% improvement in SPECfp_rate2006 benchmark results compared to the previous generation Sun Blade X6275 server module. Both nodes of a Sun Blade X6275 M2 server module using 2.93 GHz Intel Xeon X5670 processors delivered 59% improvement on the SPECint_rate2006 benchmark and 40% improvement on the SPECfp_rate2006 benchmark compared to the previous generation Sun Blade X6275 server module.

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  • Are "TDD Tests" different to Unit Tests?

    - by asgeo1
    I read this article about TDD and unit testing: http://stephenwalther.com/blog/archive/2009/04/11/tdd-tests-are-not-unit-tests.aspx I think it was an excellent article. The author makes a distinction between what he calls "TDD Tests" and unit testing. They appear to be different tests to him. Previous to reading this article I thought unit tests were a by-product of TDD. I didn't realise you might also create "TDD tests". The author seems to imply that creating unit tests is not enough for TDD as the granularity of a unit test is too small for what we are trying to achieve with TDD. So his TDD tests might test a few classes at once. At the end of the article there is some discussion from the author with some other people about whether there really is a distinction between "TDD Tests" and unit testing. Seems to be some contention around this idea. The example "TDD tests" the author showed at the end of the article just looked like normal MVC unit tests to me - perhaps "TDD tests" vs unit tests is just a matter of semantics? I would like to hear some more opinions on this, and whether there is / isn't a distinction between the two tests.

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  • SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – SQL and 10-11 May SharePoint

    - by pinaldave
    There were lots of request about providing more details for the blog post through email address specified in the article SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning. Here is the complete brochure of the course. There are two different courses are offered by Solid Quality Mentors 1) Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning – Pinal Dave Date: May 12-14, 2010 Price: Rs. 14,000/person for 3 days Discount Code: ‘SQLAuthority.com‘ Effective Price: Rs. 11,000/person for 3 days 2) SharePoint 2010 – Joy Rathnayake Date: May 10-11, 2010 Price: Rs. 11,000/person for 3 days Discount Code: ‘SQLAuthority.com’ Effective Price: Rs. 8,000/person for 3 days Download the complete PDF brochure. Additionally there is special program of SolidQ India Insider. I will provide the details for the same very soon. Please do send me email if you need any additional details. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Technology

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  • SQL SERVER – GUID vs INT – Your Opinion

    - by pinaldave
    I think the title is clear what I am going to write in your post. This is age old problem and I want to compile the list stating advantages and disadvantages of using GUID and INT as a Primary Key or Clustered Index or Both (the usual case). Let me start a list by suggesting one advantage and one disadvantage in each case. INT Advantage: Numeric values (and specifically integers) are better for performance when used in joins, indexes and conditions. Numeric values are easier to understand for application users if they are displayed. Disadvantage: If your table is large, it is quite possible it will run out of it and after some numeric value there will be no additional identity to use. GUID Advantage: Unique across the server. Disadvantage: String values are not as optimal as integer values for performance when used in joins, indexes and conditions. More storage space is required than INT. Please note that I am looking to create list of all the generic comparisons. There can be special cases where the stated information is incorrect, feel free to comment on the same. Please leave your opinion and advice in comment section. I will combine a final list and update this blog after a week. By listing your name in post, I will also give due credit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Constraint and Keys, SQL Data Storage, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • Oracle Database 11g R2 támogatott SAP alatt is

    - by Lajos Sárecz
    Húsvét óta már SAP alatt is használható az Oracle Database 11g R2. Köztudott, hogy az SAP csak a Release 2-re ad ki támogatást, így ez most egy igazán örömteli hír az SAP felhasználóknak, hiszen az alábbi 11g R2 újdonságokat tudják alkalmazni SAP környezetben: • Advanced Compression opció (táblára, RMAN mentésre, expdp-re, Data Guard hálózatra) • Real Application Testing • Oracle Database 11g Release 2 Database Vault • Oracle Database 11g Release 2 RAC • Advanced Encryption táblaterekre, RMAN mentésekre, expdp-re, Data Guard hálózatra • Direct NFS • Deferred Segments • Online Patching Azaz például tömöríthetové válik az SAP adatbázisa, vagy az abból készített mentések. Az eddigi tapasztalatok szerint a tömörítés aránya adatbázistól függoen 2-4-szeres. Az adatbázis upgrade és minden egyéb adatbázis infrastruktúrát érinto változatatás kockázata jelentosen csökkentheto lesz a Real Application Testing alkalmazásával. A rendszergazdai szerepkörök szeparaláhatóvá válnak a Database Vault felhasználásával. A Real Application Clusters 11g R2 újdonságai is elérheto lesznek. A Transparent Data Encryption révén a táblaterek és a mentések titkosíthatók úgy, hogy az alkalmazás számára mindez transzparens, azonban a médiához közvetlenül hozzáférve nem lesznek visszafejthetok az adatok. Támogatott lesz a Direct NFS kliens, ezzel NFS elérési sebesség jelentosen javul. A Deffered Segments révén pedig a tábla szegmensek csak akkor kerülnek lefoglalásra, amikor adat kerül a táblába. Ez azért hasznos, mert általában alkalmazások telepítésekor létrejön minden tábla, azonban sok táblába nem kerül adat. Ezáltal mind a telepítés ideje, mind az adatbázis mérete csökkentheto. Az Online Patching pedig lehetové teszi a leállításmentes patch telepítést. Hát azt gondolom ezek vonzó lehetoségek, érdemes betervezni a közeljövobe az SAP rendszerek alatti adatbázis frissítését, hiszen a 10g verzió Premier Support idén nyáron lejár. Az upgrade-hez pedig mindenképp javaslom a Real Application Testing használatát, amivel az éles terhelés mellett teszthelheto teszt környezetben az upgrade. A Sun Oracle Database Machine és az Exadata sajnos még nem támogatott SAP alatt, mivel az ASM certifikáció még nem zárult le. A hírek szerint 2011 elejére várható, hogy ez megtörténik.

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  • SQL SERVER – Cleaning Up SQL Server Indexes – Defragmentation, Fillfactor – Video

    - by pinaldave
    Storing data non-contiguously on disk is known as fragmentation. Before learning to eliminate fragmentation, you should have a clear understanding of the types of fragmentation. When records are stored non-contiguously inside the page, then it is called internal fragmentation. When on disk, the physical storage of pages and extents is not contiguous. We can get both types of fragmentation using the DMV: sys.dm_db_index_physical_stats. Here is the generic advice for reducing the fragmentation. If avg_fragmentation_in_percent > 5% and < 30%, then use ALTER INDEX REORGANIZE: This statement is replacement for DBCC INDEXDEFRAG to reorder the leaf level pages of the index in a logical order. As this is an online operation, the index is available while the statement is running. If avg_fragmentation_in_percent > 30%, then use ALTER INDEX REBUILD: This is replacement for DBCC DBREINDEX to rebuild the index online or offline. In such case, we can also use the drop and re-create index method.(Ref: MSDN) Here is quick video which covers many of the above mentioned topics. While Vinod and I were planning about Indexing course, we had plenty of fun and learning. We often recording few of our statement and just left it aside. Afterwords we thought it will be really funny Here is funny video shot by Vinod and Myself on the same subject: Here is the link to the SQL Server Performance:  Indexing Basics. Here is the additional reading material on the same subject: SQL SERVER – Fragmentation – Detect Fragmentation and Eliminate Fragmentation SQL SERVER – 2005 – Display Fragmentation Information of Data and Indexes of Database Table SQL SERVER – De-fragmentation of Database at Operating System to Improve Performance Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video

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  • The enterprise vendor con - connecting SSD's using SATA 2 (3Gbits) thus limiting there performance

    - by tonyrogerson
    When comparing SSD against Hard drive performance it really makes me cross when folk think comparing an array of SSD running on 3GBits/sec to hard drives running on 6GBits/second is somehow valid. In a paper from DELL (http://www.dell.com/downloads/global/products/pvaul/en/PowerEdge-PowerVaultH800-CacheCade-final.pdf) on increasing database performance using the DELL PERC H800 with Solid State Drives they compare four SSD drives connected at 3Gbits/sec against ten 10Krpm drives connected at 6Gbits [Tony slaps forehead while shouting DOH!]. It is true in the case of hard drives it probably doesn’t make much difference 3Gbit or 6Gbit because SAS and SATA are both end to end protocols rather than shared bus architecture like SCSI, so the hard drive doesn’t share bandwidth and probably can’t get near the 600MiBytes/second throughput that 6Gbit gives unless you are doing contiguous reads, in my own tests on a single 15Krpm SAS disk using IOMeter (8 worker threads, queue depth of 16 with a stripe size of 64KiB, an 8KiB transfer size on a drive formatted with an allocation size of 8KiB for a 100% sequential read test) I only get 347MiBytes per second sustained throughput at an average latency of 2.87ms per IO equating to 44.5K IOps, ok, if that was 3GBits it would be less – around 280MiBytes per second, oh, but wait a minute [...fingers tap desk] You’ll struggle to find in the commodity space an SSD that doesn’t have the SATA 3 (6GBits) interface, SSD’s are fast not only low latency and high IOps but they also offer a very large sustained transfer rate, consider the OCZ Agility 3 it so happens that in my masters dissertation I did the same test but on a difference box, I got 374MiBytes per second at an average latency of 2.67ms per IO equating to 47.9K IOps – cost of an 240GB Agility 3 is £174.24 (http://www.scan.co.uk/products/240gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-500mb-s-85k-iops), but that same drive set in a box connected with SATA 2 (3Gbits) would only yield around 280MiBytes per second thus losing almost 100MiBytes per second throughput and a ton of IOps too. So why the hell are “enterprise” vendors still only connecting SSD’s at 3GBits? Well, my conspiracy states that they have no interest in you moving to SSD because they’ll lose so much money, the argument that they use SATA 2 doesn’t wash, SATA 3 has been out for some time now and all the commodity stuff you buy uses it now. Consider the cost, not in terms of price per GB but price per IOps, SSD absolutely thrash Hard Drives on that, it was true that the opposite was also true that Hard Drives thrashed SSD’s on price per GB, but is that true now, I’m not so sure – a 300GByte 2.5” 15Krpm SAS drive costs £329.76 ex VAT (http://www.scan.co.uk/products/300gb-seagate-st9300653ss-savvio-15k3-25-hdd-sas-6gb-s-15000rpm-64mb-cache-27ms) which equates to £1.09 per GB compared to a 480GB OCZ Agility 3 costing £422.10 ex VAT (http://www.scan.co.uk/products/480gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-410mb-s-30k-iops) which equates to £0.88 per GB. Ok, I compared an “enterprise” hard drive with a “commodity” SSD, ok, so things get a little more complicated here, most “enterprise” SSD’s are SLC and most commodity are MLC, SLC gives more performance and wear, I’ll talk about that another day. For now though, don’t get sucked in by vendor marketing, SATA 2 (3Gbit) just doesn’t cut it, SSD need 6Gbit to breath and even that SSD’s are pushing. Alas, SSD’s are connected using SATA so all the controllers I’ve seen thus far from HP and DELL only do SATA 2 – deliberate? Well, I’ll let you decide on that one.

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  • SQL SERVER – Performance Tuning Resolution

    - by pinaldave
    This blog post is written in response to T-SQL Tuesday hosted by MidnightDBAs. Taking resolutions is such an interesting subject. I think just like records, these are broken way more often. I find this is the funniest thing as we all take resolutions every year but not every year, we can manage to keep them. Well, does it mean we should not take resolutions? In fact I support resolutions. Every year, I take a resolution that I will strive reduce my body weight and I usually manage to keep eating healthy till the end of January. When February begins, I begin to loose focus from my goal and as March starts, the “As usual” eating habits begin. Looking at the positive side, what would happen if every year I do not eat healthy in January, I think that might cause terrible consequences to my health in the long run. So keeping resolutions is a good practise and following them to the extent one can is commendable. Let us come back to the world of SQL Server. What is my resolution for year 2011 for SQL Server? There are many, I am going to list three of very important resolutions that I have taken this new year over here. To understand SQL Server Performance Tuning at a deeper Level I think I am already half way through. I have been being very much busy during any given month doing hands-on performance tuning for at least 12 days on an average. That means, I am doing this activity for almost doing 2 weeks a month. I believe that I have a good understanding of the subject. Note that the word that I have used is “good,” and not “best.” There are often cases when I am stumped, and I have no clue of what to do next. Then, I usually go for my “trial and error” method - whichever method works, I make sure to keep a note on my blog. My goal is that I should never ever go for the trial and error method again to achieve the same solution. I should know the solution right away when I see the problem. I do understand that Performance Tuning can be a strange animal at times and one cannot guess the right step every time. However, aiming a high goal never hurts and I am going to learn more and more in this focused area. Going further from Basic BI understanding I do fairly decent with BI concepts. I know the nbasics of SSIS, SSRS, SSAS, PowerPivot and SharePoint (and few other things MDS, StreamInsight, etc). However, I still consider myself as a beginner. I do not have hands-on experience like many other BI Gurus around. I think I want to take my learning further in this direction. I do not want to be a BI expert as the first step but the goal is to move ahead from basic level towards an advanced level. I am going to start presenting in User Group Sessions and other places on this subject. When I have to prepare new subject for presentations, I think I force myself to learn more. I am committed to learn a bit more in this direction. Learning new features SQL Server 2011 Denali This is new thing from “Microsoft” for all the SQL Geeks. I am eagerly waiting for final product later this year and I am planning to learn it well. I think if I follow my above two goals, I think this goal will be automatically covered. I am eager and excited for this new offering from Microsoft. I guess, these are my resolutions; may be next year about the same time, I must revisit this post and see how much successful I am in following my goal. On a lighter note, I am particularly fan of following cartoon strip (Courtesy: Calvin and Hobbes). I think when we cannot resolve our resolutions, we tend to act like Calvin. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Introducing NFakeMail

    - by João Angelo
    Ever had to resort to custom code to control emails sent by an application during integration and/or system testing? If you answered yes then you should definitely continue reading. NFakeMail makes it easier for developers to do integration/system testing on software that sends emails by providing a fake SMTP server. You’ll no longer have to manually validate the email sending process. It’s developed in C# and IronPython and targets the .NET 4.0 framework. With NFakeMail you can easily automate the testing of components that rely on sending mails while doing its job. Let’s take a look at some sample code, we start with a simple class containing a method that sends emails. class Notifier { public void Notify() { using (var smtpClient = new SmtpClient("localhost", 10025)) { smtpClient.Send("[email protected]", "[email protected]", "S1", "."); smtpClient.Send("[email protected]", "[email protected]", "S2", ".."); } } } Then to automate the tests for this method we only need to the following: [Test] public void Notify_T001() { using (var server = new FakeSmtpServer(10025)) { new Notifier().Notify(); // Verifies two messages are received in the next five seconds var messages = server.WaitForMessages(count: 2, timeout: 5000); // Verifies the message sender Debug.Assert(messages.All(m => m.From.Address == "[email protected]")); } } The created FakeSmtpServer instance will act as a simple SMTP server and intercept the messages sent by the Notifier class. It’s even possible to verify some fields of each intercepted message and by default all intercepted messages are saved to the file system in MIME format.

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  • TDD - Outside In vs Inside Out

    - by Songo
    What is the difference between building an application Outside In vs building it Inside Out using TDD? These are the books I read about TDD and unit testing: Test Driven Development: By Example Test-Driven Development: A Practical Guide: A Practical Guide Real-World Solutions for Developing High-Quality PHP Frameworks and Applications Test-Driven Development in Microsoft .NET xUnit Test Patterns: Refactoring Test Code The Art of Unit Testing: With Examples in .Net Growing Object-Oriented Software, Guided by Tests---This one was really hard to understand since JAVA isn't my primary language :) Almost all of them explained TDD basics and unit testing in general, but with little mention of the different ways the application can be constructed. Another thing I noticed is that most of these books (if not all) ignore the design phase when writing the application. They focus more on writing the test cases quickly and letting the design emerge by itself. However, I came across a paragraph in xUnit Test Patterns that discussed the ways people approach TDD. There are 2 schools out there Outside In vs Inside Out. Sadly the book doesn't elaborate more on this point. I wish to know what is the main difference between these 2 cases. When should I use each one of them? To a TDD beginner which one is easier to grasp? What is the drawbacks of each method? Is there any materials out there that discuss this topic specifically?

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  • Visual Studio 2010 on Macbook Air

    - by Kyle B.
    Does anyone here run Visual Studio 2010 (or VS12 RC) on a Macbook Air? I have the current model with 4GB ram, 13" screen, and 256GB SSD drive. Before I go through the effort of configuring this, I'd like to know if anyone from the community has done this and: Was the performance acceptable? If it is, I plan to get a larger cinema display monitor as a second display and do all my coding on this machine ditching my desktop. Did you use Boot camp, Parallels, or VMWare? I feel to maximize performance that boot camp would be necessary to make the most utilization of the memory, but am not sure if this completely necessary. I'd prefer to use a VM, but wasn't sure if this was practical and would value your input before buying a license. Did you also run anything else on the Windows installation, such as SQL Server express, IISExpress, etc? Did performance lag after a certain point? Note: I would have asked this in superuser.com, but felt this applied more directly to the programming community.

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  • WebLogic Server Performance and Tuning: Part II - Thread Management

    - by Gokhan Gungor
    WebLogic Server, like any other java application server, provides resources so that your applications use them to provide services. Unfortunately none of these resources are unlimited and they must be managed carefully. One of these resources is threads which are pooled to provide better throughput and performance along with the fast response time and to avoid deadlocks. Threads are execution points that WebLogic Server delivers its power and execute work. Managing threads is very important because it may affect the overall performance of the entire system. In previous releases of WebLogic Server 9.0 we had multiple execute queues and user defined thread pools. There were different queues for different type of work which had fixed number of execute threads.  Tuning of this thread pools and finding the proper number of threads was time consuming which required many trials. WebLogic Server 9.0 and the following releases use a single thread pool and a single priority-based execute queue. All type of work is executed in this single thread pool. Its size (thread count) is automatically decreased or increased (self-tuned). The new “self-tuning” system simplifies getting the proper number of threads and utilizing them.Work manager allows your applications to run concurrently in multiple threads. Work manager is a mechanism that allows you to manage and utilize threads and create rules/guidelines to follow when assigning requests to threads. We can set a scheduling guideline or priority a request with a work manager and then associate this work manager with one or more applications. At run-time, WebLogic Server uses these guidelines to assign pending work/requests to execution threads. The position of a request in the execute queue is determined by its priority. There is a default work manager that is provided. The default work manager should be sufficient for most applications. However there can be cases you want to change this default configuration. Your application(s) may be providing services that need mixture of fast response time and long running processes like batch updates. However wrong configuration of work managers can lead a performance penalty while expecting improvement.We can define/configure work managers at;•    Domain Level: config.xml•    Application Level: weblogic-application.xml •    Component Level: weblogic-ejb-jar.xml or weblogic.xml(For a specific web application use weblogic.xml)We can use the following predefined rules/constraints to manage the work;•    Fair Share Request Class: Specifies the average thread-use time required to process requests. The default is 50.•    Response Time Request Class: Specifies a response time goal in milliseconds.•    Context Request Class: Assigns request classes to requests based on context information.•    Min Threads Constraint: Limits the number of concurrent threads executing requests.•    Max Threads Constraint: Guarantees the number of threads the server will allocate to requests.•    Capacity Constraint: Causes the server to reject requests only when it has reached its capacity. Let’s create a work manager for our application for a long running work.Go to WebLogic console and select Environment | Work Managers from the domain structure tree. Click New button and select Work manager and click next. Enter the name for the work manager and click next. Then select the managed server instances(s) or clusters from available targets (the one that your long running application is deployed) and finish. Click on MyWorkManager, and open the Configuration tab and check Ignore Stuck Threads and save. This will prevent WebLogic to tread long running processes (that is taking more than a specified time) as stuck and enable to finish the process.

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  • Information about how much time in spent in a function, based on the input of this function

    - by olchauvin
    Is there a (quantitative) tool to measure performance of functions based on its input? So far, the tools I used to measure performance of my code, tells me how much time I spent in functions (like Jetbrain Dottrace for .Net), but I'd like to have more information about the parameters passed to the function in order to know which parameters impact the most the performance. Let's say that I have function like that: int myFunction(int myParam1, int myParam 2) { // Do and return something based on the value of myParam1 and myParam2. // The code is likely to use if, for, while, switch, etc.... } If would like a tool that would allow me to tell me how much time is spent in myFunction based on the value of myParam1 and myParam2. For example, the tool would give me a result looking like this: For "myFunction" : value | value | Number of | Average myParam1 | myParam2 | call | time ---------|----------|-----------|-------- 1 | 5 | 500 | 301 ms 2 | 5 | 250 | 1253 ms 3 | 7 | 1268 | 538 ms ... That would mean that myFunction has been call 500 times with myParam1=1 and myParam2=5, and that with those parameters, it took on average 301ms to return a value. The idea behind that is to do some statistical optimization by organizing my code such that, the blocs of codes that are the most likely to be executed are tested before the one that are less likely to be executed. To put it bluntly, if I know which values are used the most, I can reorganize the if/while/for etc.. structure of the function (and the whole program) to optimize it. I'd like to find such tools for C++, Java or.Net. Note: I am not looking for technical tips to optimize the code (like passing parameters as const, inlining functions, initializing the capacity of vectors and the like).

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  • Helping to Reduce Page Compression Failures Rate

    - by Vasil Dimov
    When InnoDB compresses a page it needs the result to fit into its predetermined compressed page size (specified with KEY_BLOCK_SIZE). When the result does not fit we call that a compression failure. In this case InnoDB needs to split up the page and try to compress again. That said, compression failures are bad for performance and should be minimized.Whether the result of the compression will fit largely depends on the data being compressed and some tables and/or indexes may contain more compressible data than others. And so it would be nice if the compression failure rate, along with other compression stats, could be monitored on a per table or even on a per index basis, wouldn't it?This is where the new INFORMATION_SCHEMA table in MySQL 5.6 kicks in. INFORMATION_SCHEMA.INNODB_CMP_PER_INDEX provides exactly this helpful information. It contains the following fields: +-----------------+--------------+------+ | Field | Type | Null | +-----------------+--------------+------+ | database_name | varchar(192) | NO | | table_name | varchar(192) | NO | | index_name | varchar(192) | NO | | compress_ops | int(11) | NO | | compress_ops_ok | int(11) | NO | | compress_time | int(11) | NO | | uncompress_ops | int(11) | NO | | uncompress_time | int(11) | NO | +-----------------+--------------+------+ similarly to INFORMATION_SCHEMA.INNODB_CMP, but this time the data is grouped by "database_name,table_name,index_name" instead of by "page_size".So a query like SELECT database_name, table_name, index_name, compress_ops - compress_ops_ok AS failures FROM information_schema.innodb_cmp_per_index ORDER BY failures DESC; would reveal the most problematic tables and indexes that have the highest compression failure rate.From there on the way to improving performance would be to try to increase the compressed page size or change the structure of the table/indexes or the data being stored and see if it will have a positive impact on performance.

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  • What are the design principles that promote testable code? (designing testable code vs driving design through tests)

    - by bot
    Most of the projects that I work on consider development and unit testing in isolation which makes writing unit tests at a later instance a nightmare. My objective is to keep testing in mind during the high level and low level design phases itself. I want to know if there are any well defined design principles that promote testable code. One such principle that I have come to understand recently is Dependency Inversion through Dependency injection and Inversion of Control. I have read that there is something known as SOLID. I want to understand if following the SOLID principles indirectly results in code that is easily testable? If not, are there any well-defined design principles that promote testable code? I am aware that there is something known as Test Driven Development. Although, I am more interested in designing code with testing in mind during the design phase itself rather than driving design through tests. I hope this makes sense. One more question related to this topic is whether it's alright to re-factor an existing product/project and make changes to code and design for the purpose of being able to write a unit test case for each module?

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  • How to improve Samba performance on VirtualBox machine?

    - by ColinM
    I am running a Windows 7 64bit host and Ubuntu 9.04 32bit guest inside of VirtualBox 4.0.0 on a laptop which has internet connectivity via Wifi. The main use is writing code for which I use Netbeans. My dev environment is hte virtual machine and I use Samba on the VM to share the code directory so that I can use Netbeans on the host as my IDE. Unfortunately Netbeans does a lot of disk access and due to the poor Samba performance it makes the IDE hardly usable. How can I improve performance of the Samba share? On my desktop it isn't so bad but I don't know what the difference would be since they are similar setups (Win 7 hosts, cloned guests, SSDs, Vbox guests using SATA in AHCI mode, etc..). With Bridged networking is the performance between the host and guest limited by the physical hardware (Intel 6200 AGN on laptop)? I switched to Host-only and it didn't seem to improve performance at all. To clarify bad performance, I used 7zip to zip a project directory and got 19kbs to 500kbs depending on the size of the files being zipped. On my desktop it was in the ~10mbs range. Any tips for VirtualBox/Samba configuration to get improve the performance? I am using Samba 3.3.2. Hopefully Samba with SMB2 support will be released soon..

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  • How can "today's date" be varied for unit testing purposes?

    - by ck
    I use VS2008 targetting .NET 2.0 Framework, and, just in case, no I can't change this :) I have a DateCalculator class. Its method GetNextExpirationDate attempts to determine the next expiration, internally using DateTime.Today as a baseline date. As I was writing unit tests, I realized that I wanted to test GetNextExpirationDate for different 'today' dates. What's the best way to do this? Here are some alternatives I've considered: Expose a property/overloaded method with argument baselineDate and only use it from the unit test. In actual client code, disregard the property/overloaded method in favour of the method that defaults baselineDate to DateTime.Today. I'm reluctant to do this as it makes the public interface of the DateCalculator class awkward. Create a protected field called baselineDate that is internally set to DateTime.Today. When testing, derive a DateCalculatorForTesting from DateCalculator and set baslineDate via the constructor. It keeps the public interface clean, but still isn't great - baselineDate was made protected and a derived class is required, both solely for testing. Use extension methods. I tried this after adding the ExtensionAttribute, then realized it wouldn't work because extension methods can't access private/protected variables. I initially thought this was really quite an elegant solution. :( I'd be interested in hearing what others think.

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  • Django unit testing: South-migrated DB works in MySQL, throws duplicate PK error in PostGreSQL. Am I

    - by unclaimedbaggage
    Hi folks, (Worth starting off with a disclaimer: I'm very new to PostGreSQL) I have a django site which involves a standard app/tests.py testing file. If I migrate the DB to MySQL (through South),, the tests all pass. However in PostGresQL, I'm getting the following error: IntegrityError: duplicate key value violates unique constraint "business_contact_pkey" Note this happens while unit testing only - the actual page runs fine in both MySQL & PostGresql. Really having a heckuva time figuring this one out. Anyone have ideas? Below are the Postgresql "\d business_contact" & offending tests.py method if they help. No changes made to either DB except the (same) South migrations Thanks first_name | character varying(200) | not null mobile_phone | character varying(100) | surname | character varying(200) | not null business_id | integer | not null created | timestamp with time zone | not null deleted | boolean | not null default false updated | timestamp with time zone | not null slug | character varying(150) | not null phone | character varying(100) | email | character varying(75) | id | integer | not null default nextval('business_contact_id_seq'::regclass) Indexes: "business_contact_pkey" PRIMARY KEY, btree (id) "business_contact_slug_key" UNIQUE, btree (slug) "business_contact_business_id" btree (business_id) Foreign-key constraints: "business_id_refs_id_772cc1b7b40f4b36" FOREIGN KEY (business_id) REFERENCES business(id) DEFERRABLE INITIALLY DEFERRED Referenced by: TABLE "business" CONSTRAINT "primary_contact_id_refs_id_dfaf59c4041c850" FOREIGN KEY (primary_contact_id) REFERENCES business_contact(id) DEFERRABLE INITIALLY DEFERRED TEST DEF: def test_add_business_contact(self): """ Add a business contact """ contact_slug = 'test-new-contact-added-new-adf' business_id = 1 business = Business.objects.get(id=business_id) postdata = { 'first_name': 'Test', 'surname': 'User', 'business': '1', 'slug': contact_slug, 'email': '[email protected]', 'phone': '12345678', 'mobile_phone': '9823452', 'business': 1, 'business_id': 1, } #Test to ensure contacts that should not exist are not returned contact_not_exists = Contact.objects.filter(slug=contact_slug) self.assertFalse(contact_not_exists) #Add the contact and ensure it is present in the DB afterwards """ contact_add_url = '%s%s/contact/add/' % (settings.BUSINESS_URL, business.slug) self.client.post(contact_add_url, postdata) added_contact = Contact.objects.filter(slug=contact_slug) print added_contact try: self.assertTrue(added_contact) except: formset = ContactForm(postdata) print formset.errors self.assertFalse(True, "Contact not found in the database - most likely, the post values in the test didn't validate against the form")

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  • What's the state of PHP unit testing frameworks in 2010?

    - by Pekka
    As far as I can see, PHPUnit is the only serious product in the field at the moment. It is widely used, is integrated into Continuous Integration suites like phpUnderControl, and well regarded. The thing is, I don't really like working with PHPUnit. I find it hard to set up (PEAR is the only officially supported installation method, and I hate PEAR), sometimes complicated to work with and, correct me if I'm wrong, lacking executability from a web page context (i.e. no CLI, which would really be nice when developing a web app.) The only competition to I can see is Simpletest, which looks very nice but hasn't seen a new release for almost two years, which tends to rule it out for me - Unit Testing is quite a static field, true, but as I will be deploying those tests alongside web applications, I would like to see active development on the project, at least for security updates and such. There is a SO question that pretty much confirms what I'm saying: Simple test vs PHPunit Seeing that that is almost two years old as well, though, I think it's time to ask again: Does anybody know any other serious feature-complete unit testing frameworks? Am I wrong in my criticism of PHPUnit? Is there still development going on for SimpleTest?

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