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• How are people using virtualisation with SQL Server? Part 3

  - by GavinPayneUK

  Monitoring After CPU, memory and storage, monitoring is the fourth thing which changes massively according to Brent Ozar’s list when you move to virtualisation. Some of the performance counters we used to organise our lives around become meaningless and the performance of the host server is often over-looked when looking for problems. What’s encouraging here is that the majority of people are already looking beyond the performance of virtual server and at the performance of the host server. This...(read more)

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• SQL Cruise Alaska 2011

  - by Grant Fritchey

  I had the extreme good fortune to get sent on the last SQL Cruise to Alaska. I love my job. In case you don't what this is, SQL Cruise is a trip on a cruise ship during which you get to attend classes while on the boat, learning all about SQL Server and related topics as well as network with the instructors and the other Cruisers. Frankly, it's amazing. Classes ran from Monday, 5/30, to Saturday, 6/4. The networking was constant, between classes, at night on cruise ship, out on excursions in Alaskan rainforests and while snorkeling in ocean waters. Here's a run down of the experience from my point of view. Because I couldn't travel out 2 days early, I missed the BBQ that occurred the day before the cruise when many of the Cruisers received their swag bags. Some of that swag came from Red Gate. I researched what was useful on a cruise like this and purchased small flashlights and binoculars for all the Cruisers. The flashlights were because, depending on your cabin, ships can be very dark. The binoculars were so that the cruisers could watch all the beautiful landscape as it flowed by. I would have liked to have been there when the bags were opened, but I heard from several people that they appreciated the gifts. Cruisers "In" the hot tub. Pictured: Marjory Woody, Michele Grondin, Kyle Brandt, Grant Fritchey, John Halunen Sunday I went to board the ship with my wife. We had a bit of an adventure because I messed up our documents. It all worked out and we got on board to meet up at the back of the boat at one of the outdoor bars with the other Cruisers, thanks to tweets letting everyone know where to go. That was the end of electronic coordination on the trip (connectivity in Alaska was horrible for everyone except AT&T). The Cruisers were a great bunch of people and it was a real honor to meet them and get to spend time with them. After everyone settled into their cabins, our very first activity was a contest, sponsored by Red Gate. The Cruisers, in an effort to get to know each other and the ship, were required to go all over taking various photographs, some of them hilarious. The winning team of three would all win prizes. Some of the significant others helped out and I tagged along with a team that tied for first but lost the coin toss. The winning team consisted of Christina Leo (blog|twitter), Ryan Malcom (twitter), Neil Hambly (blog|twitter). They then had to do math and identify the cabin with the lowest prime number, oh, and get a picture of it and be the first to get back up to the bar where we were waiting. Christina came in first and very happily carried home an Ipad2. Ryan won a 1TB portable hard drive and Neil won a wireless mouse (picture below, note my special SQL Server Central Friday Shirt. Thanks Steve (blog|twitter)). Winners: Christina Leo, Neil Hambly, Ryan Malcolm. Just Lucky: Grant Fritchey Monday morning classes started. Buck Woody (blog|twitter) was a special guest speaker on this cruise. His theme was "Three C's on the High Seas: Career, Communication and Cloud." The first session was all on Career. I'm not going to type out all my notes from the session, but let's just say, if you get the chance to hear Buck talk about how to manage your career, I suggest you attend. I have a ton of blog posts that I'll be putting together over the next several months (yes, months) both here and over on ScaryDBA. I also have a bunch of work I'm going to be doing to get my career performance bumped up a notch or two (and let's face it, that won't be easy). Later on Monday, Tim Ford (blog|twitter) did a session on DMOs. Specifically the session was on Tim's Period Table of DMOs that he has put together, and how to use some of the more interesting DMOs in your day to day job. It was a great session, packed with good information. Next, Brent Ozar (blog|twitter) did a session on how to monitor and guide SAN configuration for the DBA that doesn't have access to the SAN. That was some seriously useful information. Tuesday morning we only had a single class. Kendra Little (blog|twitter) taught us all about "No Lock for Yes Fun".  It was all about the different transaction isolation levels and how they work. There is so often confusion in this area and Kendra does a great job in clarifying the information. Also, she tosses in her excellent drawings to liven up the presentation. Then it was excursion time in Juneau. My wife and I, along with several other Cruisers, took a hike up around the Mendenhall Glacier. It was absolutely beautiful weather and walking through the Alaskan rain forest was a treat. Our guide, Jason, was a great guy and it was a good day of hiking. Wednesday was an all day excursion in Skagway. My wife and I took the "Ghost and Good Time Girls" walking tour that ended up at a bar that used to be a brothel, the Red Onion. It was a great history of the town. We went back out and hit a few museums and exhibits. We also hiked up the side of the mountain to see the Dewey Lake and some great views of the town. Finally we hiked out to the far side of town to see the Gold Rush cemetery. Hiking done we went back to the boat and had a quiet dinner on our own. Thursday we cruised through Glacier Bay and saw at least four different glaciers including sitting next to the Marjory Glacier for  about an hour. It was amazing. Then it got better. We went into class with Buck again, this time to talk about Communication. Again, I've got pages of notes that I'm going to be referring back to for some time to come. This was an excellent opportunity to learn. Snorkelers: Nicole Bertrand, Aaron Bertrand, Grant Fritchey, Neil Hambly, Christina Leo, John Robel, Yanni Robel, Tim Ford Friday we pulled into Ketchikan. A bunch of us went snorkeling. Yes, snorkeling. Yes, in Alaska. Yes, snorkeling in the ocean in Alaska. It was fantastic. They had us put on 7mm thick wet suits (an adventure all by itself) so it was basically warm the entire time we were in the water (except for the occasional squirt of cold water down my back). Before we got in the water a bald eagle flew up and landed about 15 feet in front of us, which was just an incredible event. Then our guide pointed out about 14 other eagles in the area, hanging out in the trees. Wow! The water was pretty clear and there was a ton of things to see. That was absolutely a blast. Back on the boat I presented a session called Execution Plans: The Deep Dive (note the nautical theme). It seemed to go over well and I had several good questions come out of the session that will lead to new blog posts. After I presented, it was Aaron Bertrand's (blog|twitter) turn. He did a session on "What's New in Denali" that provided a lot of great information. He was able to incorporate new things straight out of Tech-Ed, so this was expanded beyond his usual presentation. The man really knows what he's talking about and communicates it well. Saturday we were travelling so there was time for a bunch of classes. Jeremiah Peschka (blog|twitter) did a great overview of some of the NoSQL databases and what they should be used for. The session was called "The Database is Dead" but it was really about how there are specific uses for these databases that SQL Server doesn't fill, but also that these databases can't replace SQL Server in other areas. Again, good material. Brent Ozar presented again with a session on Defensive Indexing. It was an overview of how indexes work and a deep dive into how to apply them appropriately in your databases to better support access. A good session, as you would expect. Then we pulled into Victoria, BC, in Canada and had a nice dinner with several of the Cruisers, including Denny Cherry (blog|twitter). After that it was back to Seattle on Sunday. By the way, the Science Fiction Museum in Seattle isn't a Science Fiction Museum any more. I was very disappointed to discover this. Overall, it was a great experience. I'm extremely appreciative of Red Gate for sending me and for Tim, Brent, Kendra and Jeremiah for having me. The other Cruisers were all amazing people and it was an honor & privilege to meet them and spend time with them. While this was a seriously fun time, it was also a very serious training opportunity with solid information coming from seasoned industry pros.

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• Top 10 Linked Blogs of 2010

  - by Bill Graziano

  Each week I send out a SQL Server newsletter and include links to interesting blog posts.  I’ve linked to over 500 blog posts so far in 2010.  Late last year I started storing those links in a database so I could do a little reporting.  I tend to link to posts related to the OLTP engine.  I also try to link to the individual blogger in the group blogs.  Unfortunately that wasn’t possible for the SQLCAT and CSS blogs.  I also have a real weakness for posts related to PASS. These are the top 10 blogs that I linked to during the year ordered by the number of posts I linked to. Paul Randal – Paul writes extensively on the internals of the relational engine.  Lots of great posts around transactions, transaction log, disaster recovery, corruption, indexes and DBCC.  I also linked to many of his SQL Server myths posts. Glenn Berry – Glenn writes very interesting posts on how hardware affects SQL Server.  I especially like his posts on the various CPU platforms.  These aren’t necessarily topics that I’m searching for but I really enjoy reading them. The SQLCAT Team – This Microsoft team focuses on the largest and most interesting SQL Server installations.  The regularly publish white papers and best practices. SQL Server CSS Team – These are the top engineers from the Microsoft Customer Service and Support group.  These are the folks you finally talk to after your case has been escalated about 20 times.  They write about the interesting problems they find. Brent Ozar – The posts I linked to mostly focused on the relational engine: CPU, NUMA, SSD drives, performance monitoring, etc.  But Brent writes about a real variety of topics including blogging, social networking, speaking, the MCM, SQL Azure and anything else that seems to strike his fancy.  His posts are always well written and though provoking. Jeremiah Peschka – A number of Jeremiah’s posts weren’t about SQL Server.  He’s very active in the “NoSQL” area and I linked to a number of those posts.  I think it’s important for people to know what other technologies are out there. Brad McGehee – Brad writes about being a DBA including maintenance plans, DBA checklists, compression and audit. Thomas LaRock – I linked to a variety of posts from PBM to networking to 24 Hours of PASS to TDE.  Just a real variety of topics.  Tom always writes with an interesting style usually mixing in a movie theme and/or bacon. Aaron Bertrand – Many of my links this year were Denali features.  He also had a great series on bad habits to kick. Michael J. Swart – This last one surprised me.  There are some well known SQL Server bloggers below Michael on this list.  I linked to posts on indexes, hierarchies, transactions and I/O performance and a variety of other engine related posts.  All are interesting and well thought out.  Many of his non-SQL posts are also very good.  He seems to have an interest in puzzles and other brain teasers.  Michael, I won’t be surprised again!

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• PASS Summit 2011 &ndash; Part II

  - by Tara Kizer

  I arrived in Seattle last Monday afternoon to attend PASS Summit 2011.  I had really wanted to attend Gail Shaw’s (blog|twitter) and Grant Fritchey’s (blog|twitter) pre-conference seminar “All About Execution Plans” on Monday, but that would have meant flying out on Sunday which I couldn’t do.  On Tuesday, I attended Allan Hirt’s (blog|twitter) pre-conference seminar entitled “A Deep Dive into AlwaysOn: Failover Clustering and Availability Groups”.  Allan is a great speaker, and his seminar was packed with demos and information about AlwaysOn in SQL Server 2012.  Unfortunately, I have lost my notes from this seminar and the presentation materials are only available on the pre-con DVD.  Hmpf! On Wednesday, I attended Gail Shaw’s “Bad Plan! Sit!”, Andrew Kelly’s (blog|twitter) “SQL 2008 Query Statistics”, Dan Jones’ (blog|twitter) “Improving your PowerShell Productivity”, and Brent Ozar’s (blog|twitter) “BLITZ! The SQL – More One Hour SQL Server Takeovers”.  In Gail’s session, she went over how to fix bad plans and bad query patterns.  Update your stale statistics! How to fix bad plans Use local variables – optimizer can’t sniff it, so it’ll optimize for “average” value Use RECOMPILE (at the query or stored procedure level) – CPU hit OPTIMIZE FOR hint – most common value you’ll pass How to fix bad query patterns Don’t use them – ha! Catch-all queries Use dynamic SQL OPTION (RECOMPILE) Multiple execution paths Split into multiple stored procedures OPTION (RECOMPILE) Modifying parameter values Use local variables Split into outer and inner procedure OPTION (RECOMPILE) She also went into “last resort” and “very last resort” options, but those are risky unless you know what you are doing.  For the average Joe, she wouldn’t recommend these.  Examples are query hints and plan guides. While I enjoyed Andrew’s session, I didn’t take any notes as it was familiar material.  Andrew is a great speaker though, and I’d highly recommend attending his sessions in the future. Next up was Dan’s PowerShell session.  I need to look into profiles, manifests, function modules, and function import scripts more as I just didn’t quite grasp these concepts.  I am attending a PowerShell training class at the end of November, so maybe that’ll help clear it up.  I really enjoyed the Excel integration demo.  It was very cool watching PowerShell build the spreadsheet in real-time.  I must look into this more!  On a side note, I am jealous of Dan’s hair.  Fabulous hair! Brent’s session showed us how to quickly gather information about a server that you will be taking over database administration duties for.  He wrote a script to do a fast health check and then later wrapped it into a stored procedure, sp_Blitz.  I can’t wait to use this at my work even on systems where I’ve been the primary DBA for years, maybe there’s something I’ve overlooked.  We are using EPM to help standardize our environment and uncover problems, but sp_Blitz will definitely still help us out.  He even provides a cloud-based update feature, sp_BlitzUpdate, for sp_Blitz so you don’t have to constantly update it when he makes a change.  I think I’ll utilize his update code for some other challenges that we face at my work.

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• Is it OK to run perfmon on production servers? And why?

  - by Bill Paetzke

  Or should perfmon be limited to a Dev/QA server with load tests that simulate production activity? I'd like to run perfmon for a two days (like Sql Server master Brent Ozar suggests) to get an overall feel of my web app's database performance.

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• How to bring Paging File usage metric to zero?

  - by AngryHacker

  I am trying to tune a SQL Server. Per Brent Ozar's Performance Tuning Video, he says the PerfMon's Paging File:%Usage should be zero or ridiculously close to it. The average metric on my box is around 1.341% The box has 18 GB of RAM, the SQL Server is off, the Commit Charge Total is 1GB and yet the PerfMon metric is not 0. The Performance of the Task Manager states that PF Usage is 1.23GB. What should I do to better tune the box?

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• A Taxonomy of Numerical Methods v1

  - by JoshReuben

  Numerical Analysis – When, What, (but not how) Once you understand the Math & know C++, Numerical Methods are basically blocks of iterative & conditional math code. I found the real trick was seeing the forest for the trees – knowing which method to use for which situation. Its pretty easy to get lost in the details – so I’ve tried to organize these methods in a way that I can quickly look this up. I’ve included links to detailed explanations and to C++ code examples. I’ve tried to classify Numerical methods in the following broad categories: Solving Systems of Linear Equations Solving Non-Linear Equations Iteratively Interpolation Curve Fitting Optimization Numerical Differentiation & Integration Solving ODEs Boundary Problems Solving EigenValue problems Enjoy – I did ! Solving Systems of Linear Equations Overview Solve sets of algebraic equations with x unknowns The set is commonly in matrix form Gauss-Jordan Elimination http://en.wikipedia.org/wiki/Gauss%E2%80%93Jordan_elimination C++: http://www.codekeep.net/snippets/623f1923-e03c-4636-8c92-c9dc7aa0d3c0.aspx Produces solution of the equations & the coefficient matrix Efficient, stable 2 steps: · Forward Elimination – matrix decomposition: reduce set to triangular form (0s below the diagonal) or row echelon form. If degenerate, then there is no solution · Backward Elimination –write the original matrix as the product of ints inverse matrix & its reduced row-echelon matrix à reduce set to row canonical form & use back-substitution to find the solution to the set Elementary ops for matrix decomposition: · Row multiplication · Row switching · Add multiples of rows to other rows Use pivoting to ensure rows are ordered for achieving triangular form LU Decomposition http://en.wikipedia.org/wiki/LU_decomposition C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-lu-decomposition-for-solving.html Represent the matrix as a product of lower & upper triangular matrices A modified version of GJ Elimination Advantage – can easily apply forward & backward elimination to solve triangular matrices Techniques: · Doolittle Method – sets the L matrix diagonal to unity · Crout Method - sets the U matrix diagonal to unity Note: both the L & U matrices share the same unity diagonal & can be stored compactly in the same matrix Gauss-Seidel Iteration http://en.wikipedia.org/wiki/Gauss%E2%80%93Seidel_method C++: http://www.nr.com/forum/showthread.php?t=722 Transform the linear set of equations into a single equation & then use numerical integration (as integration formulas have Sums, it is implemented iteratively). an optimization of Gauss-Jacobi: 1.5 times faster, requires 0.25 iterations to achieve the same tolerance Solving Non-Linear Equations Iteratively find roots of polynomials – there may be 0, 1 or n solutions for an n order polynomial use iterative techniques Iterative methods · used when there are no known analytical techniques · Requires set functions to be continuous & differentiable · Requires an initial seed value – choice is critical to convergence à conduct multiple runs with different starting points & then select best result · Systematic - iterate until diminishing returns, tolerance or max iteration conditions are met · bracketing techniques will always yield convergent solutions, non-bracketing methods may fail to converge Incremental method if a nonlinear function has opposite signs at 2 ends of a small interval x1 & x2, then there is likely to be a solution in their interval – solutions are detected by evaluating a function over interval steps, for a change in sign, adjusting the step size dynamically. Limitations – can miss closely spaced solutions in large intervals, cannot detect degenerate (coinciding) solutions, limited to functions that cross the x-axis, gives false positives for singularities Fixed point method http://en.wikipedia.org/wiki/Fixed-point_iteration C++: http://books.google.co.il/books?id=weYj75E_t6MC&pg=PA79&lpg=PA79&dq=fixed+point+method++c%2B%2B&source=bl&ots=LQ-5P_taoC&sig=lENUUIYBK53tZtTwNfHLy5PEWDk&hl=en&sa=X&ei=wezDUPW1J5DptQaMsIHQCw&redir_esc=y#v=onepage&q=fixed%20point%20method%20%20c%2B%2B&f=false Algebraically rearrange a solution to isolate a variable then apply incremental method Bisection method http://en.wikipedia.org/wiki/Bisection_method C++: http://numericalcomputing.wordpress.com/category/algorithms/ Bracketed - Select an initial interval, keep bisecting it ad midpoint into sub-intervals and then apply incremental method on smaller & smaller intervals – zoom in Adv: unaffected by function gradient à reliable Disadv: slow convergence False Position Method http://en.wikipedia.org/wiki/False_position_method C++: http://www.dreamincode.net/forums/topic/126100-bisection-and-false-position-methods/ Bracketed - Select an initial interval , & use the relative value of function at interval end points to select next sub-intervals (estimate how far between the end points the solution might be & subdivide based on this) Newton-Raphson method http://en.wikipedia.org/wiki/Newton's_method C++: http://www-users.cselabs.umn.edu/classes/Summer-2012/csci1113/index.php?page=./newt3 Also known as Newton's method Convenient, efficient Not bracketed – only a single initial guess is required to start iteration – requires an analytical expression for the first derivative of the function as input. Evaluates the function & its derivative at each step. Can be extended to the Newton MutiRoot method for solving multiple roots Can be easily applied to an of n-coupled set of non-linear equations – conduct a Taylor Series expansion of a function, dropping terms of order n, rewrite as a Jacobian matrix of PDs & convert to simultaneous linear equations !!! Secant Method http://en.wikipedia.org/wiki/Secant_method C++: http://forum.vcoderz.com/showthread.php?p=205230 Unlike N-R, can estimate first derivative from an initial interval (does not require root to be bracketed) instead of inputting it Since derivative is approximated, may converge slower. Is fast in practice as it does not have to evaluate the derivative at each step. Similar implementation to False Positive method Birge-Vieta Method http://mat.iitm.ac.in/home/sryedida/public_html/caimna/transcendental/polynomial%20methods/bv%20method.html C++: http://books.google.co.il/books?id=cL1boM2uyQwC&pg=SA3-PA51&lpg=SA3-PA51&dq=Birge-Vieta+Method+c%2B%2B&source=bl&ots=QZmnDTK3rC&sig=BPNcHHbpR_DKVoZXrLi4nVXD-gg&hl=en&sa=X&ei=R-_DUK2iNIjzsgbE5ID4Dg&redir_esc=y#v=onepage&q=Birge-Vieta%20Method%20c%2B%2B&f=false combines Horner's method of polynomial evaluation (transforming into lesser degree polynomials that are more computationally efficient to process) with Newton-Raphson to provide a computational speed-up Interpolation Overview Construct new data points for as close as possible fit within range of a discrete set of known points (that were obtained via sampling, experimentation) Use Taylor Series Expansion of a function f(x) around a specific value for x Linear Interpolation http://en.wikipedia.org/wiki/Linear_interpolation C++: http://www.hamaluik.com/?p=289 Straight line between 2 points à concatenate interpolants between each pair of data points Bilinear Interpolation http://en.wikipedia.org/wiki/Bilinear_interpolation C++: http://supercomputingblog.com/graphics/coding-bilinear-interpolation/2/ Extension of the linear function for interpolating functions of 2 variables – perform linear interpolation first in 1 direction, then in another. Used in image processing – e.g. texture mapping filter. Uses 4 vertices to interpolate a value within a unit cell. Lagrange Interpolation http://en.wikipedia.org/wiki/Lagrange_polynomial C++: http://www.codecogs.com/code/maths/approximation/interpolation/lagrange.php For polynomials Requires recomputation for all terms for each distinct x value – can only be applied for small number of nodes Numerically unstable Barycentric Interpolation http://epubs.siam.org/doi/pdf/10.1137/S0036144502417715 C++: http://www.gamedev.net/topic/621445-barycentric-coordinates-c-code-check/ Rearrange the terms in the equation of the Legrange interpolation by defining weight functions that are independent of the interpolated value of x Newton Divided Difference Interpolation http://en.wikipedia.org/wiki/Newton_polynomial C++: http://jee-appy.blogspot.co.il/2011/12/newton-divided-difference-interpolation.html Hermite Divided Differences: Interpolation polynomial approximation for a given set of data points in the NR form - divided differences are used to approximately calculate the various differences. For a given set of 3 data points , fit a quadratic interpolant through the data Bracketed functions allow Newton divided differences to be calculated recursively Difference table Cubic Spline Interpolation http://en.wikipedia.org/wiki/Spline_interpolation C++: https://www.marcusbannerman.co.uk/index.php/home/latestarticles/42-articles/96-cubic-spline-class.html Spline is a piecewise polynomial Provides smoothness – for interpolations with significantly varying data Use weighted coefficients to bend the function to be smooth & its 1st & 2nd derivatives are continuous through the edge points in the interval Curve Fitting A generalization of interpolating whereby given data points may contain noise à the curve does not necessarily pass through all the points Least Squares Fit http://en.wikipedia.org/wiki/Least_squares C++: http://www.ccas.ru/mmes/educat/lab04k/02/least-squares.c Residual – difference between observed value & expected value Model function is often chosen as a linear combination of the specified functions Determines: A) The model instance in which the sum of squared residuals has the least value B) param values for which model best fits data Straight Line Fit Linear correlation between independent variable and dependent variable Linear Regression http://en.wikipedia.org/wiki/Linear_regression C++: http://www.oocities.org/david_swaim/cpp/linregc.htm Special case of statistically exact extrapolation Leverage least squares Given a basis function, the sum of the residuals is determined and the corresponding gradient equation is expressed as a set of normal linear equations in matrix form that can be solved (e.g. using LU Decomposition) Can be weighted - Drop the assumption that all errors have the same significance –-> confidence of accuracy is different for each data point. Fit the function closer to points with higher weights Polynomial Fit - use a polynomial basis function Moving Average http://en.wikipedia.org/wiki/Moving_average C++: http://www.codeproject.com/Articles/17860/A-Simple-Moving-Average-Algorithm Used for smoothing (cancel fluctuations to highlight longer-term trends & cycles), time series data analysis, signal processing filters Replace each data point with average of neighbors. Can be simple (SMA), weighted (WMA), exponential (EMA). Lags behind latest data points – extra weight can be given to more recent data points. Weights can decrease arithmetically or exponentially according to distance from point. Parameters: smoothing factor, period, weight basis Optimization Overview Given function with multiple variables, find Min (or max by minimizing –f(x)) Iterative approach Efficient, but not necessarily reliable Conditions: noisy data, constraints, non-linear models Detection via sign of first derivative - Derivative of saddle points will be 0 Local minima Bisection method Similar method for finding a root for a non-linear equation Start with an interval that contains a minimum Golden Search method http://en.wikipedia.org/wiki/Golden_section_search C++: http://www.codecogs.com/code/maths/optimization/golden.php Bisect intervals according to golden ratio 0.618.. Achieves reduction by evaluating a single function instead of 2 Newton-Raphson Method Brent method http://en.wikipedia.org/wiki/Brent's_method C++: http://people.sc.fsu.edu/~jburkardt/cpp_src/brent/brent.cpp Based on quadratic or parabolic interpolation – if the function is smooth & parabolic near to the minimum, then a parabola fitted through any 3 points should approximate the minima – fails when the 3 points are collinear , in which case the denominator is 0 Simplex Method http://en.wikipedia.org/wiki/Simplex_algorithm C++: http://www.codeguru.com/cpp/article.php/c17505/Simplex-Optimization-Algorithm-and-Implemetation-in-C-Programming.htm Find the global minima of any multi-variable function Direct search – no derivatives required At each step it maintains a non-degenerative simplex – a convex hull of n+1 vertices. Obtains the minimum for a function with n variables by evaluating the function at n-1 points, iteratively replacing the point of worst result with the point of best result, shrinking the multidimensional simplex around the best point. Point replacement involves expanding & contracting the simplex near the worst value point to determine a better replacement point Oscillation can be avoided by choosing the 2nd worst result Restart if it gets stuck Parameters: contraction & expansion factors Simulated Annealing http://en.wikipedia.org/wiki/Simulated_annealing C++: http://code.google.com/p/cppsimulatedannealing/ Analogy to heating & cooling metal to strengthen its structure Stochastic method – apply random permutation search for global minima - Avoid entrapment in local minima via hill climbing Heating schedule - Annealing schedule params: temperature, iterations at each temp, temperature delta Cooling schedule – can be linear, step-wise or exponential Differential Evolution http://en.wikipedia.org/wiki/Differential_evolution C++: http://www.amichel.com/de/doc/html/ More advanced stochastic methods analogous to biological processes: Genetic algorithms, evolution strategies Parallel direct search method against multiple discrete or continuous variables Initial population of variable vectors chosen randomly – if weighted difference vector of 2 vectors yields a lower objective function value then it replaces the comparison vector Many params: #parents, #variables, step size, crossover constant etc Convergence is slow – many more function evaluations than simulated annealing Numerical Differentiation Overview 2 approaches to finite difference methods: · A) approximate function via polynomial interpolation then differentiate · B) Taylor series approximation – additionally provides error estimate Finite Difference methods http://en.wikipedia.org/wiki/Finite_difference_method C++: http://www.wpi.edu/Pubs/ETD/Available/etd-051807-164436/unrestricted/EAMPADU.pdf Find differences between high order derivative values - Approximate differential equations by finite differences at evenly spaced data points Based on forward & backward Taylor series expansion of f(x) about x plus or minus multiples of delta h. Forward / backward difference - the sums of the series contains even derivatives and the difference of the series contains odd derivatives – coupled equations that can be solved. Provide an approximation of the derivative within a O(h^2) accuracy There is also central difference & extended central difference which has a O(h^4) accuracy Richardson Extrapolation http://en.wikipedia.org/wiki/Richardson_extrapolation C++: http://mathscoding.blogspot.co.il/2012/02/introduction-richardson-extrapolation.html A sequence acceleration method applied to finite differences Fast convergence, high accuracy O(h^4) Derivatives via Interpolation Cannot apply Finite Difference method to discrete data points at uneven intervals – so need to approximate the derivative of f(x) using the derivative of the interpolant via 3 point Lagrange Interpolation Note: the higher the order of the derivative, the lower the approximation precision Numerical Integration Estimate finite & infinite integrals of functions More accurate procedure than numerical differentiation Use when it is not possible to obtain an integral of a function analytically or when the function is not given, only the data points are Newton Cotes Methods http://en.wikipedia.org/wiki/Newton%E2%80%93Cotes_formulas C++: http://www.siafoo.net/snippet/324 For equally spaced data points Computationally easy – based on local interpolation of n rectangular strip areas that is piecewise fitted to a polynomial to get the sum total area Evaluate the integrand at n+1 evenly spaced points – approximate definite integral by Sum Weights are derived from Lagrange Basis polynomials Leverage Trapezoidal Rule for default 2nd formulas, Simpson 1/3 Rule for substituting 3 point formulas, Simpson 3/8 Rule for 4 point formulas. For 4 point formulas use Bodes Rule. Higher orders obtain more accurate results Trapezoidal Rule uses simple area, Simpsons Rule replaces the integrand f(x) with a quadratic polynomial p(x) that uses the same values as f(x) for its end points, but adds a midpoint Romberg Integration http://en.wikipedia.org/wiki/Romberg's_method C++: http://code.google.com/p/romberg-integration/downloads/detail?name=romberg.cpp&can=2&q= Combines trapezoidal rule with Richardson Extrapolation Evaluates the integrand at equally spaced points The integrand must have continuous derivatives Each R(n,m) extrapolation uses a higher order integrand polynomial replacement rule (zeroth starts with trapezoidal) à a lower triangular matrix set of equation coefficients where the bottom right term has the most accurate approximation. The process continues until the difference between 2 successive diagonal terms becomes sufficiently small. Gaussian Quadrature http://en.wikipedia.org/wiki/Gaussian_quadrature C++: http://www.alglib.net/integration/gaussianquadratures.php Data points are chosen to yield best possible accuracy – requires fewer evaluations Ability to handle singularities, functions that are difficult to evaluate The integrand can include a weighting function determined by a set of orthogonal polynomials. Points & weights are selected so that the integrand yields the exact integral if f(x) is a polynomial of degree <= 2n+1 Techniques (basically different weighting functions): · Gauss-Legendre Integration w(x)=1 · Gauss-Laguerre Integration w(x)=e^-x · Gauss-Hermite Integration w(x)=e^-x^2 · Gauss-Chebyshev Integration w(x)= 1 / Sqrt(1-x^2) Solving ODEs Use when high order differential equations cannot be solved analytically Evaluated under boundary conditions RK for systems – a high order differential equation can always be transformed into a coupled first order system of equations Euler method http://en.wikipedia.org/wiki/Euler_method C++: http://rosettacode.org/wiki/Euler_method First order Runge–Kutta method. Simple recursive method – given an initial value, calculate derivative deltas. Unstable & not very accurate (O(h) error) – not used in practice A first-order method - the local error (truncation error per step) is proportional to the square of the step size, and the global error (error at a given time) is proportional to the step size In evolving solution between data points xn & xn+1, only evaluates derivatives at beginning of interval xn à asymmetric at boundaries Higher order Runge Kutta http://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods C++: http://www.dreamincode.net/code/snippet1441.htm 2nd & 4th order RK - Introduces parameterized midpoints for more symmetric solutions à accuracy at higher computational cost Adaptive RK – RK-Fehlberg – estimate the truncation at each integration step & automatically adjust the step size to keep error within prescribed limits. At each step 2 approximations are compared – if in disagreement to a specific accuracy, the step size is reduced Boundary Value Problems Where solution of differential equations are located at 2 different values of the independent variable x à more difficult, because cannot just start at point of initial value – there may not be enough starting conditions available at the end points to produce a unique solution An n-order equation will require n boundary conditions – need to determine the missing n-1 conditions which cause the given conditions at the other boundary to be satisfied Shooting Method http://en.wikipedia.org/wiki/Shooting_method C++: http://ganeshtiwaridotcomdotnp.blogspot.co.il/2009/12/c-c-code-shooting-method-for-solving.html Iteratively guess the missing values for one end & integrate, then inspect the discrepancy with the boundary values of the other end to adjust the estimate Given the starting boundary values u1 & u2 which contain the root u, solve u given the false position method (solving the differential equation as an initial value problem via 4th order RK), then use u to solve the differential equations. Finite Difference Method For linear & non-linear systems Higher order derivatives require more computational steps – some combinations for boundary conditions may not work though Improve the accuracy by increasing the number of mesh points Solving EigenValue Problems An eigenvalue can substitute a matrix when doing matrix multiplication à convert matrix multiplication into a polynomial EigenValue For a given set of equations in matrix form, determine what are the solution eigenvalue & eigenvectors Similar Matrices - have same eigenvalues. Use orthogonal similarity transforms to reduce a matrix to diagonal form from which eigenvalue(s) & eigenvectors can be computed iteratively Jacobi method http://en.wikipedia.org/wiki/Jacobi_method C++: http://people.sc.fsu.edu/~jburkardt/classes/acs2_2008/openmp/jacobi/jacobi.html Robust but Computationally intense – use for small matrices < 10x10 Power Iteration http://en.wikipedia.org/wiki/Power_iteration For any given real symmetric matrix, generate the largest single eigenvalue & its eigenvectors Simplest method – does not compute matrix decomposition à suitable for large, sparse matrices Inverse Iteration Variation of power iteration method – generates the smallest eigenvalue from the inverse matrix Rayleigh Method http://en.wikipedia.org/wiki/Rayleigh's_method_of_dimensional_analysis Variation of power iteration method Rayleigh Quotient Method Variation of inverse iteration method Matrix Tri-diagonalization Method Use householder algorithm to reduce an NxN symmetric matrix to a tridiagonal real symmetric matrix vua N-2 orthogonal transforms     Whats Next Outside of Numerical Methods there are lots of different types of algorithms that I’ve learned over the decades: Data Mining – (I covered this briefly in a previous post: http://geekswithblogs.net/JoshReuben/archive/2007/12/31/ssas-dm-algorithms.aspx ) Search & Sort Routing Problem Solving Logical Theorem Proving Planning Probabilistic Reasoning Machine Learning Solvers (eg MIP) Bioinformatics (Sequence Alignment, Protein Folding) Quant Finance (I read Wilmott’s books – interesting) Sooner or later, I’ll cover the above topics as well.

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• Going to the Score Cards - Exceptional DBA Awards 2011

  - by Rodney

  This year marks my 4th year as a judge for the Exceptional DBA Awards, founded by Red Gate in 2008 to "recognize the essential but often overlooked contributions of DBAs, the unsung heroes of the IT community." As a professional DBA myself I have been honored to participate as a judge. It is not an easy job because there is a voluminous amount of nominees from all over the world. Each judge has to read through every word of the nominee's answers, deciding what makes each person special and stand out amongst their peers. What drives them? What single element of their submission will shine above all others? It is my hope that what I am about to divulge to you as a judge will prompt you to think about yourself or someone you know and decide that you may be the exceptional DBA who can take home the gold at this year's award ceremony in Seattle. We are more than a few weeks into the nomination process and there are quite a number of submissions already. I can not tell you how many as that would not be fair. I can say it is not 1 million or more. I can also say that it is not 100,000. But that is all I can say about that. However, I can tell you that it is enough this year that we are breaking records on the number of people who have been influenced, inspired or intrigued by the awards in the past. I remember them all like it were yesterday. fuzzy thought cloud here. It was a rainy day in Seattle (all memories for each award ceremony will start thusly) and I was in the hotel going over my notes on what I wanted to say about the winner of the 2008 Red Gate Exceptional DBA Award. The notes were on index cards that I had either bought or stolen from my wife, I do not recall, but I was nervous which was unlike me. This was, after all, a big night for the winner. Of course, we, the judges and the SQL community, had already decided the winner and now all that remained was to present the award. The room was packed. It was Casino night, sponsored by sqlservercentral.com. Money (fake), drinks (not fake) and camaraderie flowed through the room. Dan McClain won the award that year. He worked for Anheuser-Busch at the time. I promise that did not influence my decision. We presented Dan with the award. He was very proud of this achievement, rightfully so, as was the SQL community for him. I spoke with Dan throughout the conference and realized how huge this award was for him, not just personally but professionally. It was a rainy day in Seattle in 2009 and I was nervous. I was asked to speak to a group of people again as a judge for the Exceptional DBA Awards. This year, Josef Richberg would be the recipient of the award, but he would not be able to attend. We all prayed for him as he fought through an illness and congratulated him for his accomplishments as a DBA for his company. He got better and sallied forth and continued to give back to the SQL community that he saw as one big family. In 2010, and I am getting ahead of myself, he was asked to be a judge himself for the very award he had just received the year before. It was a sunny day in Seattle and I missed it, because it was in July and I was not there. It was a rainy day in Seattle and it is 2010 and Tracy Hamlin enters a submission that blows this judge away. She is managing a 50 Terabyte distributed database ("50 Gigabytes! Are you kidding me!!!", Rodney jokes.)  and loves her daily job as a DBA working with developers, mentoring them and teaching them best practices with kindness and patience. She is a people person who just happens to have 10+ years experience with RDBMS'. She wins the award and goes on to be recognized as famous at PASS. It will be a rainy day in Seattle this year when I sit amongst my old constituent judges and friends, Brad McGehee, http://www.simple-talk.com/books/sql-books/how-to-become-an-exceptional-dba,-2nd-edition/, Steve Jones, whom we all know and love at http://www.sqlservercentral.com and a young upstart to the SQL Community, this cat named Brent Ozar to announce the 2011 winner. I personally have not heard of Brent but I am told I have interviewed him for a DBA position several years ago and turned him down, http://www.brentozar.com/archive/2011/05/exceptional-dba-contest/ . I hope that did not jeopardize his future in the SQL world. I am a big hearted oaf and would feel horrible. Hopefully I will meet him at PASS and we can work this all out and I can help him get a DBA job. The rain has stopped and a new year is upon us. The stakes are high...the competition is fierce...the rewards are incredible. The entry form awaits you. http://www.exceptionaldba.com/ I very much look forward to meeting you and presenting the award to you in front of hundreds of your envious but proud peers as the new Exceptional DBA for 2011 at the PASS Summit. Here is what you could win: The Exceptional DBA of the Year receives full conference registration for the 2011 PSS Summit in Seattle, where the awards ceremony will take place, four nights' hotel accommodation, and $300 towards travel expenses. They will also be featured on Simple-Talk. Are you ready? Are you nervous?

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• Sessions I Submitted to the PASS Summit 2010

  - by andyleonard

  Introduction I'm borrowing an idea and blog post title from Brent Ozar ( Blog - @BrentO ). I am honored the PASS Summit 2010 (Seattle, 8 - 11 Nov 2010) would consider allowing me to present. It's a truly awesome event. If you have an opportunity to attend and read this blog, please find me and introduce yourself. If you've built a cool solution to a business or technical problem; or written a script - or a bunch of scripts - to automate part of your daily / weekly / monthly routine; or have some...(read more)

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• Welcome to Jackstown

  - by fatherjack

  I live in a small town, the population count isn't that great but let me introduce you to some of the population. We'll start with Martin the Doc, he fixes up anything that gets poorly, so much so that he could be classed as the doctor, the vet and even the garage mechanic. He's got a reputation that he can fix anything and that hasn't been proved wrong yet. He's great friends with Brian (who gets called "Brains") the teacher who seems to have a sound understanding of any topic you care to pass his way. If he isn't sure he tells you and then goes to find out and comes back with a full answer real quick. Its good to have that sort of research capability close at hand. Brains is also great at encouraging anyone who needs a bit of support to get them up to speed and working on their jobs. Steve sees Brains regularly, that's because he is the librarian, he keeps all sorts of reading material and nowadays there's even video to watch about any topic you like. Steve keeps scouring all sorts of places to get the content that's needed and he keeps it in good order so that what ever is needed can be found quickly. He also has to make sure that old stuff gets marked as probably out of date so that anyone reading it wont get mislead. Over the road from him is Greg, he's the town crier. We don't have a newspaper here so Greg keeps us all informed of what's going on "out of town" - what new stuff we might make use of and what wont work in a small place like this. If we are interested he goes ahead and gets people in to demonstrate their products  and tell us about the details. Greg is pretty good at getting us discounts too. Now Greg's brother Ian works for the mayors office in the "waste management department" nowadays its all about the recycling but he still has to make sure that the stuff that cant be used any more gets disposed of properly. It depends on the type of waste he's dealing with that decides how it need to be treated and he has to know a lot about the different methods and when to use which ones. There are two people that keep the peace in town, Brent is the detective, investigating wrong doings and applying justice where necessary and Bart is the diplomat who smooths things over when any people have a dispute or disagreement. Brent is meticulous in his investigations and fair in the way he handles any situation he finds. Discretion is his byword. There's a rumour that Bart used to work for the United Nations but what ever his history there is no denying his ability to get apparently irreconcilable parties working together to their combined benefit. Someone who works closely with Bart is Brad, he is the translator in town. He has several languages that he can converse in but he can also explain things from someone's point of view or  and make it understandable to someone else. To keep things on the straight and narrow from a legal perspective is Ben the solicitor, making sure we all abide by the rules.Two people who make for an interesting evening's conversation if you get them together are Aaron and Grant, Aaron is the local planning inspector and Grant is an inventor of some reputation. Anything being constructed around here needs Aarons agreement. He's quite flexible in his rules though; if you can justify what you want to do with solid logic but he wont stand for any development going on without his inclusion. That gets a demolition notice and there's no argument. Grant as I mentioned is the inventor in town, if something can be improved or created then Grant is your man. He mainly works on his own but isnt averse to getting specific advice and assistance from specialist from out of town if they can help him finish his creations.There aren't too many people left for you to meet in the town, there's Rob, he's an ex professional sportsman. He played Hockey, Football, Cricket, you name it. He was in his element as goal keeper / wicket keeper and that shows in his personal life. He just goes about his business and people often don't even know that he's helped them. Really low profile, doesn't get any glory but saves people from lots of problems, even disasters on occasion. There goes Neil, he's a bit of an odd person, some people say he's gifted with special clairvoyant powers, personally I think he's got his ear to the ground and knows where to find out the important news as soon as its made public. Anyone getting a visit from Neil is best off to follow his advice though, he's usually spot on and you wont be caught by surprise if you follow his recommendations – wherever it comes from.Poor old Andrew is the last person to introduce you to. Andrew doesn't show himself too often but when he does it seems that people find a reason to blame him for their problems, whether he had anything to do with their predicament or not. In all honesty, without fail, and to his great credit, he takes it in good grace and never retaliates or gets annoyed when he's out and about.  It pays off too as its very often the case that those who were blaming him recently suddenly find they need his help and they readily forget the issues pretty rapidly.And then there's me, what do I do in town? Well, I'm just a DBA with a lot of hats. (Jackstown Pop. 1)

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• Pain of the Week/Expert's Perspective: Performance Tuning for Backups and Restores

  - by KKline

  First off - the Pain of the Week webcast series has been renamed. It's now known as The Expert's Perspective . Please join us for future webcasts and, if you're interested in speaking, drop me a note to see if we can get you on the roster! The bigger your databases get, the longer backups take. That doesn't really seem like a huge problem — until disaster strikes and you need to restore your databases as fast as possible. Join my buddy Brent Ozar ( blog | twitter ), a Microsoft Certified Master of...(read more)

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• That’s a wrap! Almost, there’s still one last chance to attend a SQL in the City event in 2012

  - by Red and the Community

  The communities team are back from the SQL in the City multi-city US Tour and we are delighted to have met so many happy SQL Server professionals and Red Gate customers. We set out to run a series of back-to-back events in order to meet, talk to and delight as many SQL Server and Red Gate enthusiasts as possible in 5 different cities in 11 days. We did it! The attendees had a good time too and 99% of them would attend another SQL in the City event in 2013 – so it seems we left an impression. There were a range of topics on the event agenda, ranging from ‘The Whys & Hows of Continuous Integration’, ‘Database Maintenance Essentials’, ‘Red Gate tools – The Complete Lifecycle’, ‘Automated Deployment: Application And Database Releases Without The Headache’, ‘The Ten Commandments of SQL Server Monitoring’ and many more. Videos and slides from the events will be posted to the event website in November, after our last event of 2012. SQL in the City Seattle – November 5 Join us for free and hear from some of the very best names in the SQL Server world. SQL Server MVPs such as; Steve Jones, Grant Fritchey, Brent Ozar, Gail Shaw and more will be presenting at the Bell Harbor conference center for one day only. We’re even taking on board some of the recent attendee-suggestions of how we can improve the events (feedback from the 65% of attendees who came to our US tour events), first off we’re extending the drinks celebration in the evening! Rather than just a 30 minute drink and run, attendees will have up to 2 hours to enjoy free drinks, relax and network in a fantastic environment amongst some really smart like-minded professionals. If you’re interested in expanding your SQL Server knowledge, would like to learn more about Red Gate tools, get yourself registered for the last SQL in the City event of 2012. It’s free, fun and we’re very friendly! I look forward to seeing you in Seattle on Monday November 5. Cheers, Annabel.

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• Social meet up on Twitter for MEET Windows Azure on June the 7th

  - by shiju

  Get ready to MEET Windows Azure live on June the 7th. The Microsoft Windows Azure team is conducting an online event “Meet Windows Azure” on June 7th 2012 starting at 1 PM PDT. The event will be presented by Scott Guthrie. If you want to watch event  live, you can register here: http://register.meetwindowsazure.com/.   If you are planning to attend the event and want to be social, there is a Social meet up on Twitter event organized by Windows Azure MVP Magnus Martensson MEET Windows Azure Blog Relay: Roger Jennings (@rogerjenn): Social meet up on Twitter for Meet Windows Azure on June 7th Anton Staykov (@astaykov): MEET Windows Azure on June the 7th Patriek van Dorp (@pvandorp): Social Meet Up for ‘MEET Windows Azure’ on June 7th Marcel Meijer (@MarcelMeijer): MEET Windows Azure on June the 7th Nuno Godinho (@NunoGodinho): Social Meet Up for ‘MEET Windows Azure’ on June 7th Shaun Xu (@shaunxu) Let's MEET Windows Azure Maarten Balliauw (@maartenballiauw): Social meet up on Twitter for MEET Windows Azure on June 7th Brent Stineman (@brentcodemonkey): Meet Windows Azure (aka Learn Windows Azure v2) Herve Roggero (@hroggero): Social Meet up on Twitter for Meet Windows Azure on June 7th Paras Doshi (@paras_doshi): Get started on Windows Azure: Attend “Meet Windows Azure” event Online Simran Jindal (@SimranJindal): Meet Windows Azure – an online and in person event, social meetup #MeetAzure (+ Beer for Beer lovers) on June 7th 2012 Magnus Mårtensson (@noopman): Social meet up on Twitter for MEET Windows Azure on June 7th Kris van der Mast (@KvdM): Shiju Varghese (@shijucv) Social meet up on Twitter for MEET Windows Azure on June the 7th I hope to see you online for the social meet event on the 7th. My Twitter user name is @shijucv Call to action: Link to this blog post on your blog and I will update this post to link to you.

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• 4 Top Tips from the Exceptional DBA Award judges

  - by Rebecca Amos

  There's still time to celebrate your achievements as a DBA – or those of a DBA you know – by submitting a nomination for the Exceptional DBA Awards 2011. To help you get started, here are some top tips from the judges on what they're looking for from this year's winner [hint: it's very likely you're already exceptional!]: "An Exceptional DBA must be able to communicate effectively and clearly with both technical people and the client." Steve Jones. "Exceptional DBAs are like police officers: we're here to serve and protect. Both serving and protecting are vital parts of the job, and we can't just focus on one." Brent Ozar "DBA work can be routine. Exceptional DBAs are enthusiastic about their work and are rarely bored, as there is always something new to learn and master." Brad McGehee. "Remember that cost is an important factor for your company. The ability to save your company money with a different technical solution will make you an Exceptional DBA, and can make you exceptionally well liked." Rodney Landrum. So whether you've brought a team together for a project, taken steps to protect the security of your servers, or learnt a new topic to understand an element of your job better, it's likely you’re already taking the steps that make you the Exceptional DBA the judges are looking for. To get more insider info from the judges, download your free poster of their top tips, and then get started on your entry: www.exceptionaldba.com.

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• SQLAuthority News – Free Trip on SQL Cruise

  - by pinaldave

  Everybody wants to go cruising.  I want to relax in a cruise as well, of course! (Anybody who wants to be my sponsor? Just kidding!) My family wants to go to a cruise, too. Even though I really want go to a cruise, I always wonder about one thing: what happens if I get bored on the cruise because I’d just look at the water most of the time? The best recommendation to avoid boredom on board is to travel with friends. How many friends usually accompany you when travelling? I have several good friends going on a cruise, and this is the reason why I want to go to SQL Cruise. One of them is Brent, who I consider as my friend. (Tim, you are my friend, too!) Now, we all have an opportunity to travel for free. Idera is offering a trip to SQL Cruise for FREE. To win a FREE SQL Cruise trip, you have to to do a very simple thing: just talk about How you saved the day You can tell your story via a video, photo, poem, or interpretive dance. If you refer to superheroes and Idera product, you will gain more credits to win. WHAT YOU CAN WIN: A 5-day cruise for two from Miami to Grand Cayman and Cozumel 1 seat in the SQLcruise training Airfare for two to Miami (up to $1000) Please read for further details over here. Make sure you participate and submit your entry within January 5 up to 21, 2011. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SharePoint 2007 / 2010 Content Indexing &ldquo;The file reached the maximum download limit. Check that the full text of the document can be meaningfully crawled.&rdquo;

  - by Stacy Vicknair

  If you have large files in a content source that is being indexed by Sharepoint you might run into the following error message: “The file reached the maximum download limit. Check that the full text of the document can be meaningfully crawled.” This is usually caused because SharePoint’s MaxDownloadSize setting is set lower than the size of the file you are attempting to index. You can increase this value, restart the service then kick off a full crawl in order to fix this issue, but SharePoint 2007 and 2010 have different methods for accomplishing this task.   Sharepoint 2007 Open up the Registry editor and increase the MaxDownloadSize value to a number (in MB) higher than the largest file being indexed. You can find this at: HKEY_LOCAL_MACHINE\Software\Microsoft\Search\1.0\Gathering Manager After you increase the size, cycle the search service and kick off a full crawl of the content source in question.   Sharepoint 2010 With SharePoint 2010 you can use PowerShell via the Sharepoint 2010 Console in order to change the MaxDownloadSize. Execute the following commands to update the value: 1: $ssa = Get-SPEnterpriseSearchServiceApplication 2: $ssa.SetProperty(“MaxDownloadSize”, <new size in MB>) 3: $ssa.Update()   References: http://support.microsoft.com/kb/287231 http://blogs.technet.com/b/brent/archive/2010/07/19/sharepoint-server-2010-maxdownloadsize-and-maxgrowfactor.aspx   Technorati Tags: SharePoint,WSS,MaxDownloadSize,Search

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• My first blog post…

  - by steveh99999

  I’ve been meaning to start a blog for a while now, (OK, for several years…..) - finally now, here it begins First post, something really simple but, a wise-man once told me about the best way to improve SQL server performance. Store Less Data. That's it.. that's all there is to it... Over the years, I've seen the following :- -  a 200Gb database which held 3 days data. Once business requirements changed, we were able to hold only 1 days data in this database. -  a table developed by DBAs to hold application table cardinality information - that information was collected at 2 hour intervals every day for 7 years ! After 7 years the DBA space-info table had become the largest table in the database - 60 million rows !  It was a simple change to remove alot of the historical intra-day data and change the schedule to run only once per evening. Suddenly that table held 6 million rows instead of 60 million.... - lots of backup and restore history held in msdb. See this post by Brent Ozar for more details on this issue. Imagine how much faster the backups, DBCC Checks and reindexes ran when the above 3 changes were implemented ?   How often do you review your big databases \ tables to see if you’re actually holding only data that is really required by the business ?

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• Computer Says No: Mobile Apps Connectivity Messages

  - by ultan o'broin

  Sharing some insight into connectivity messages for mobile applications. Based on some recent ethnography done my myself, and prompted by a real business case, I would recommend a message that: In plain language, briefly and directly tells the user what is wrong and why. Something like: Cannot connect because of a network problem. Affords the user a means to retry connecting (or attempts automatically). Mobile context of use means users use anticipate interruptibility and disruption of task, so they will try again as an effective course of action. Tells the user when connection is re-established, and off they go. Saves any work already done, implicitly. (Bonus points on the ADF critical task setting scale) The following images showing my experience reading ADF-EMG Google Groups notification my (Android ICS) Samsung Galaxy S2 during a loss of WiFi give you a good idea of a suitable kind of messaging user experience for mobile apps in this kind of scenario. Inline connection lost message with Retry button Connection re-established toaster message The UX possible is dependent on device and platform features, sure, so remember to integrate with the device capability (see point 10 of this great article on mobile design by Brent White and Lynn Hnilo-Rampoldi) but taking these considerations into account is far superior to a context-free dumbed down common error message repurposed from the desktop mentality about the connection to the server being lost, so just "Click OK" or "Contact your sysadmin.".

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• TechEd 2012: Fast SQL Server

  - by Tim Murphy

  While I spend a certain amount of my time creating databases (coding around SQL Server and setup a server when I have to) it isn’t my bread and butter.  Since I have run into a number of time that SQL Server needed to be tuned I figured I would step out of my comfort zone and see what I can learn. Brent Ozar packed a mountain of information into his session on making SQL Server faster.  I’m not sure how he found time to hit all of his points since he was allowing the audience abuse him on Twitter instead of asking questions, but he managed it.  I also questioned his sanity since he appeared to be using a fruit laptop. He had my attention though when he stated that he had given up on telling people to not use “select *”. He posited that it could be fixed with hardware by caching the data in memory.  He continued by cautioning that having too many indexes could defeat this approach.  His logic was sound if not always practical, but it was a good place to start when determining the trade-offs you need to balance.  He was moving pretty fast, but I believe he was prescribing this solution predominately for OLTP database prior to moving on to data warehouse solutions. Much of the advice he gave for data warehouses is contained in the Microsoft Fast Track guidance so I won’t rehash it here.  To summarize the solution seems to be the proper balance memory, disk access speed and the speed of the pipes that get the data from storage to the CPU.  It appears to be sound guidance and the session gave enough information that going forward we should be able to find the details needed easily.  Just what the doctor ordered. del.icio.us Tags: SQL Server,TechEd,TechEd 2012,Database,Performance Tuning

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• SQLAuthority News – SQLPASS Nov 8-11, 2010-Seattle – An Alternative Look at Experience

  - by pinaldave

  I recently attended most prestigious SQL Server event SQLPASS between Nov 8-11, 2010 at Seattle. I have only one expression for the event - Best Summit Ever This year the summit was at its best. Instead of writing about my usual routine or the event, I am going to write about the interesting things I did and how I felt about it! Best Summit Ever Trip to Seattle! This was my second trip to Seattle this year and the journey is always long. Here is the travel stats on how long it takes to get to Seattle: 24 hours official air time 36 hours total travel time (connection waits and airport commute) Every time I travel to USA I gain a day and when I travel back to home, I lose a day. However, the total traveling time is around 3 days. The journey is long and very exhausting. However, it is all worth it when you’re attending an event like SQLPASS. Here are few things I carry when I travel for a long journey: Dry Snack packs – I like to have some good Indian Dry Snacks along with me in my backpack so I can have my own snack when I want Amazon Kindle – Loaded with 80+ books A physical book – This is usually a very easy to read book I do not watch movies on the plane and usually spend my time reading something quick and easy. If I can go to sleep, I go for it. I prefer to not to spend time in conversation with the guy sitting next to me because usually I end up listening to their biography, which I cannot blog about. Sheraton Seattle SQLPASS In any case, I love to go to Seattle as the city is great and has everything a brilliant metropolis has to offer. The new Light Train is extremely convenient, and I can take it directly from the airport to the city center. My hotel, the Sheraton, was only few meters (in the USA people count in blocks – 3 blocks) away from the train station. This time I saved USD 40 each round trip due to the Light Train. Sessions I attended! Well, I really wanted to attend most of the sessions but there was great dilemma of which ones to choose. There were many, many sessions to be attended and at any given time there was more than one good session being presented. I had decided to attend sessions in area performance tuning and I attended quite a few sessions this year, compared to what I was able to do last year. Here are few names of the speakers whose sessions I attended (please note, following great speakers are not listed in any order. I loved them and I enjoyed their sessions): Conor Cunningham Rushabh Mehta Buck Woody Brent Ozar Jonathan Kehayias Chris Leonard Bob Ward Grant Fritchey I had great fun attending their sessions. The sessions were meaningful and enlightening. It is hard to rate any session but I have found that the insights learned in Conor Cunningham’s sessions are the highlight of the PASS Summit. Rushabh Mehta at Keynote SQLPASS   Bucky Woody and Brent Ozar I always like the sessions where the speaker is much closer to the audience and has real world experience. I think speakers who have worked in the real world deliver the best content and most useful information. Sessions I did not like! Indeed there were few sessions I did not like it and I am not going to name them here. However, there were strong reasons I did not like their sessions, and here is why: Sessions were all theory and had no real world connections. All technical questions ended with confusing answers (lots of “I will get back to you on it,” “it depends,” “let us take this offline” and many more…) “I am God” kind of attitude in the speakers For example, I attended a session of one very well known speaker who is a specialist for one particular area. I was bit late for the session and was surprised to see that in a room that could hold 350 people there were only 30 attendees. After sitting there for 15 minutes, I realized why lots of people left. Very soon I found I preferred to stare out the window instead of listening to that particular speaker. One on One Talk! Many times people ask me what I really like about PASS. I always say the experience of meeting SQL legends and spending time with them one on one and LEARNING! Here is the quick list of the people I met during this event and spent more than 30 minutes with each of them talking about various subjects: Pinal Dave and Brad Shulz Pinal Dave and Rushabh Mehta Michael Coles and Pinal Dave Rushabh Mehta – It is always pleasure to meet with him. He is a man with lots of energy and a passion for community. He recently told me that he really wanted to turn PASS into resource for learning for every SQL Server Developer and Administrator in the world. I had great in-depth discussion regarding how a single person can contribute to a community. Michael Coles – I consider him my best friend. It is always fun to meet him. He is funny and very knowledgeable. I think there are very few people who are as expert as he is in encryption and spatial databases. Worth meeting him every single time. Glenn Berry – A real friend of everybody. He is very a simple person and very true to his heart. I think there is not a single person in whole community who does not like him. He is a friends of all and everybody likes him very much. I once again had time to sit with him and learn so much from him. As he is known as Dr. DMV, I can be his nurse in the area of DMV. Brad Schulz – I always wanted to meet him but never got chance until today. I had great time meeting him in person and we have spent considerable amount of time together discussing various T-SQL tricks and tips. I do not know where he comes up with all the different ideas but I enjoy reading his blog and sharing his wisdom with me. Jonathan Kehayias – He is drill sergeant in US army. If you get the impression that he is a giant with very strong personality – you are wrong. He is very kind and soft spoken DBA with strong performance tuning skills. I asked him how he has kept his two jobs separate and I got very good answer – just work hard and have passion for what you do. I attended his sessions and his presentation style is very unique.  I feel like he is speaking in a language I understand. Louis Davidson – I had never had a chance to sit with him and talk about technology before. He has so much wisdom and he is very kind. During the dinner, I had talked with him for long time and without hesitation he started to draw a schema for me on the menu. It was a wonderful experience to learn from a master at the dinner table. He explained to me the real and practical differences between third normal form and forth normal form. Honestly I did not know earlier, but now I do. Erland Sommarskog – This man needs no introduction, he is very well known and very clear in conveying his ideas. I learned a lot from him during the course of year. Every time I meet him, I learn something new and this time was no exception. Joe Webb – Joey is all about community and people, we had interesting conversation about community, MVP and how one can be helpful to community without losing passion for long time. It is always pleasant to talk to him and of course, I had fun time. Ross Mistry – I call him my brother many times because he indeed looks like my cousin. He provided me lots of insight of how one can write book and how he keeps his books simple to appeal to all the readers. A wonderful person and great friend. Ola Hallgren - I did not know he was coming to the summit. I had great time meeting him and had a wonderful conversation with him regarding his scripts and future community activities. Blythe Morrow – She used to be integrated part of SQL Server Community and PASS HQ. It was wonderful to meet her again and re-connect. She is wonderful person and I had a great time talking to her. Solid Quality Mentors – It is difficult to decide who to mention here. Instead of writing all the names, I am going to include a photo of our meeting. I had great fun meeting various members of our global branches. This year I was sitting with my Spanish speaking friends and had great fun as Javier Loria from Solid Quality translated lots of things for me. Party, Party and Parties Every evening there were various parties. I did attend almost all of them. Every party had different theme but the goal of all the parties the same – networking. Here are the few parties where I had lots of fun: Dell Reception Party Exhibitor Party Solid Quality Fun Party Red Gate Friends Party MVP Dinner Microsoft Party MVP Dinner Quest Party Gameworks PASS Party Volunteer Party at Garage Solid Quality Mentors (10 Members out of 120) They were all great networking opportunities and lots of fun. I really had great time meeting people at the various parties. There were few people everywhere – well, I will say I am among them – who hopped parties. NDA – Not Decided Agenda During the event there were few meetings marked “NDA.” Someone asked me “why are these things NDA?”  My response was simple: because they are not sure themselves. NDA stands for Not Decided Agenda. Toys, Giveaways and Luggage I admit, I was like child in Gameworks and was playing to win soft toys. I was doing it for my daughter. I must thank all of the people who gave me their cards to try my luck. I won 4 soft-toys for my daughter and it was fun. Also, thanks to Angel who did a final toy swap with me to get the desired toy for my daughter. I also collected ducks from Idera, as my daughter really loves them. Solid Quality Booth Each of the exhibitors was giving away something and I got so much stuff that my luggage got quite a bit bigger when I returned. Best Exhibitor Idera had SQLDoctor (a real magician and fun guy) to promote their new tool SQLDoctor. I really had a great time participating in the magic myself. At one point, the magician made my watch disappear.  I have seen better magic before, but this time it caught me unexpectedly and I was taken by surprise. I won many ducks again. The Common Question I heard the following common questions: I have seen you somewhere – who are you? – I am Pinal Dave. I did not know that Pinal is your first name and Dave is your last name, how do you pronounce your last name again? – Da-way How old are you? – I am as old as I can be. Are you an Indian because you look like one? – I did not answer this one. Where are you from? This question was usually asked after looking at my badge which says India. So did you really fly from India? – Yes, because I have seasickness so I do not prefer the sea journey. How long was the journey? – 24/36/12 (air travel time/total travel time/time zone difference) Why do you write on SQLAuthority.com? – Because I want to. I remember your daughter looks like you. – Is this even a question? Of course, she is daddy’s little girl. There were so many other questions, I will have to write another blog post about it. SQLPASS Again, Best Summit Ever! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, Pinal Dave, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology Tagged: SQLPASS

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• Why use MVVM???

  - by LnDCobra

  Okay, I have been looking into MVVM pattern, and each time I have previously tried looking into it, I gave up for a number of reasons: Unnecessary Extra Long Winded Coding No apparent advantages for coders (no designers in my office. Currently only myself soon to be another coder) Not a lot of resources/documentation of good practices! (Or at least hard to find) Cannot think of a single scenario where this is advantageous. I'm about to give up on it yet again, and thought I'd ask to see if someone answer the reasons above. I honestly can't see an advantage of using this for a single/partner coding. Even in complex projects with 10's of windows. To me the DataSet is a good enough view and binding like in the answer by Brent following question

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• Exceptional DBA Awards 2011

  - by Rebecca Amos

  From today, we’re accepting nominations for the 2011 Exceptional DBA Awards. DBAs make a vital contribution to the running of the companies they work for, and the Exceptional DBA Awards aim to acknowledge this and make this contribution more widely known. Check out our new website for all the info: www.exceptionaldba.com  Being an exceptional DBA doesn’t mean you have to sleep at the office, or know everything there is to know about SQL Server; who ever could? It means that you make an effort to make your servers secure and reliable, and to make your users’ lives easier. Maybe you’ve helped a junior colleague learn something new about server backups? Or cancelled your coffee break to get a database back online? Or contributed to a forum post on performance monitoring? All of these actions show that you might be an exceptional DBA. So have a think about the tasks you do every day that already make you exceptional – and then get started on your entry! You just need to answer a few questions on our website about your experience as a DBA, some of your biggest achievements, and any other activities you participate in within the SQL Server community. Anyone who is currently working as a SQL Server database administrator can enter, or be nominated by someone else. We’ve got four fantastic judges for the Awards, who you’ll be familiar with already: Brent Ozar, Brad McGehee, Rodney Landrum and Steve Jones. They’ll pick five finalists, and then we’ll ask the SQL Server community to vote for their winner. Not only could you win the respect and recognition of peers and colleagues, but the prizes also include full conference registration for the 2011 PASS Summit in Seattle (where the awards ceremony will take place), four nights' hotel accommodation, and $300 towards travel expenses. The winner will get a copy of Red Gate’s SQL DBA Bundle – and they’ll also be featured here, on Simple-Talk. So what are you waiting for? Chances are you’ve already made a small effort for someone today that means you might be an exceptional DBA. Visit the website now, and start writing your entry – or nominate your favourite DBA to enter: www.exceptionaldba.com

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• Going for Gold

  - by Simple-Talk Editorial Team

  There was a spring in the step of some members of our development teams here at Red Gate, on hearing that on five gold awards at 2012′s SQL Mag Community and Editors Choice Awards. And why not? It’s a nice recognition that their efforts were appreciated by many in the SQL Server community. The team at Simple-Talk don’t tend to spring, but even we felt a twinge of pride in the fact that SQL Scripts Manager received Gold for Editor’s Choice in the Best Free Tools category. The tool began life as a “Down Tools” project and is one that we’ve supported and championed in various articles on Simple-talk.com. Over a Cambridge Bitter in the Waggon and Horses, we’ve often reflected on how nice it would be to nominate our own awards. Of course, we’d have to avoid nominating Red Gate tools in each category, even the free ones, for fear of seeming biased,  but we could still award other people’s free tools, couldn’t we? So allow us to set the stage for the annual Simple-Talk Community Tool awards… Onto the platform we shuffle, to applause from the audience; Chris in immaculate tuxedo, Alice in stunning evening gown, Dave and Tony looking vaguely uncomfortable, Andrew somehow distracted, as if his mind is elsewhere. Tony strides up to the lectern, and coughs lightly…”In the free-tool category we have the three nominations, and they are…” (rustle of the envelope opening) Ola Hallengren’s SQL Server Maintenance Solution (applause) Adam Machanic’s WhoIsActive (cheers, more applause) Brent Ozar’s sp_Blitz (much clapping) “Before we declare the winner, I’d like to say a few words in recognition of a grand tradition in a SQL Server community that continues to offer its members a steady supply of excellent, free tools. It hammers home the fundamental principle that a tool should solve a single, pressing and frustrating problem, but you should only ever build your own solution to that problem if you are certain that you cannot buy it, or that someone has not already provided it free. We have only three finalists tonight, but I feel compelled to mention a few other tools that we also use and appreciate, such as Microsoft’s Logparser, Open source Curl, Microsoft’s TableDiff.exe, Performance Analysis of Logs (PAL) Tool, SQL Server Cache Manager and SQLPSX.” “And now I’ll hand over to Alice to announce the winner.” Alice strides over to the microphone, tearing open the envelope. “The winner,” she pauses for dramatic effect “… is …Ola Hallengren’s SQL Server Maintenance Solution!” Queue much applause and consumption of champagne. Did we get it wrong? What free tool would you nominate? Let us know! Cheers, Simple-Talk Editorial Team (Andrew, Alice, Chris, Dave, Tony)

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• IT Admin for Thrill Seekers

  - by Tony Davis

  A developer suggested to me recently that the life of the DBA was, surely, a dull one. My first reaction was indignation, but quickly followed by the thought that for many people excitement isn't necessarily the most desirable aspect of their job. It's true that some aspects of the DBA role seem guaranteed to quieten the pulse; in the days of tape backups, time must have slowed to eternity for the person whose job it was to oversee this process, placing tapes into secure containers, ensuring correct labeling, and.sorry, I drifted off there for a second. On the other hand, if you follow the adventures of the likes of Brent Ozar or Tom LaRock, you'd be forgiven for thinking that much of a database guy's time is spent, metaphorically, diving through plate glass windows in tight fitting underwear in order to extract grateful occupants from burning database applications. Alas it isn't true of the majority, but it isn't as dull as some people imagine, and is a helter-skelter ride compared with some other IT roles. Every IT department has people who toil away in shadowy corners doing quiet but mysterious tasks. When you ask them to explain what they do, you almost immediately want them to stop, but you hear enough to appreciate that these tasks are often absolutely vital to the smooth functioning of an IT organization. Compared with them, the DBAs are prima donnas. Here are a few nominations: Installation engineer - install all of the company's laptops and workstations, and software, deal with licensing, shipping and data entry.many organizations, especially those subject to tight regulation, would simply grind to a halt without their efforts. Localization engineer - Not quite software engineering, not quite translation, the job is to rebuild a product in a different language and make sure everything still works. QA Tester - firstly, I should say that the testers at Red Gate seem to me some of the most-fulfilled in the company. I refer here to the QA Tester whose job is more-or-less entirely to read a script, click some buttons and make sure the actual and expected values match. Configuration manager - for example, someone whose main job is to configure build environments so that devs can access their source code; assuredly necessary for the smooth functioning and productivity of the team, and hopefully well-paid. So what other sort of job in IT should one choose if the work of a DBA proves to be too exciting? Or are these roles secretly more exciting than many imagine? I invite you all to put forward your own suggestions. Cheers, Tony.

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• Database Mirroring – deprecated

  - by fatherjack

  Do you use mirroring on any of your databases? Do you use mirroring on SQL Server Standard Edition? I do, as a way of having a stand-by server ready to take over if there is a problem with the live server so that business can continue despite whatever disaster may strike at our primary server location. In my experience it has been a great solution for us as it is simple to implement, reliable and predictable. Mirroring has been around since SQL Server 2005 sp1 but with the release of SQL Server 2012 mirroring has now been placed on the deprecation list. That’s right, Microsoft are removing this feature from SQL Server. SQL Server 2012 had lots of improvements and new features around this sort of technology – the High Availability, Disaster recovery and Always On features described in detail here by Brent Ozar and  Microsoft’s own Customer Service and Support SQL Server Engineers . Now the bad news, the HADRON features are pretty much all wrapped up in the Enterprise Edition of SQL Server 2012. This is going to be a big issue for people, like me, who are only on Standard Edition of earlier versions mostly due to our requirements and the budget (or lack thereof) required for Enterprise Edition licenses. No mirroring in Standard Edition means no upgrade. Don’t Panic. There are two stages of deprecation and they dont happen fast. The first stage – Deprecation Announcement- means that Microsoft have decided that there is a limited future for a particular feature and this is your cue that new projects and developments should not be implemented on this technology as it will cease to exist in the future. This is where mirroring currently stands. You have time to consider your options and start work on planning how you will move away from using this feature. This can be 2 or 3 versions of SQL Server, possibly more. The next stage is Deprecation Final Support - this is where you are on your last chance, When you see this then the next version of SQL Server will not have this feature in it so you need to implement your plans to move to an alternative solution. While these two phases are taking place Microsoft are open to feedback on how people use their products and if enough people make the case for mirroring (or an equivalent technology) to be in the Standard Edition then they may make changes rather than lose customers or have customers cease upgrading in order to keep the functionality they need. Denny Cherry (@MrDenny) has published an article on this same topic here with more detail than me so I wont go over old ground. All I will say is that you should read his article now and then follow the link to his own site where he is collecting peoples information on how they use mirroring in Standard Edition so that our voice can be put to Microsoft.  

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