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• SQL SERVER – What is Spatial Database? – Developing with SQL Server Spatial and Deep Dive into Spati

  - by pinaldave

  What is Spatial Database? A spatial database is a database that is optimized to store and query data related to objects in space, including points, lines and polygons. While typical databases can understand various numeric and character types of data, additional functionality needs to be added for databases to process spatial data types. (Source: Wikipedia) Today I will be talking about the same subject at Microsoft TechEd India. If you want to learn about how to spatial aspect of data and how to integrate them with SQL Server this is the perfect session for you. Spatial is very special concept of SQL Server and I really like how it is implemented in SQL Server. In general Performance Tuning and Query Optimization is something I always have enjoyed in my professional life. Index are my best friends and many time, by implementing and many time by removing I have improved the performance of the system. In this session, I will be talking about Index along with Spatial Data. As Spatial Database is very interesting concept, I will cover super short but very interesting 10 quick slides about this subject. I will make sure in very first 20 mins, you will understand following topics Introduction to Spatial Database One line definition Understanding Spatial Indexing Index Internals Query/Performance Tuning Query Hinting/Cost Analysis Spatial Index Catalog Views Performance Troubleshooting Finding Optimal Index using Spatial Index SP Common Errors Index Maintenance This slides decks will be followed by around 30 mins demo which will have story of geometry, geography, index internals and performance tuning. If you are interested in learning how GIS works and how SQL Server out of the box supports this wonderful tools, you will really like how the story is told. I am sure all people who attend the event will know how the Bangalore is positioned on the map of India. I will take example of Bangalore and Hyderabad and demonstrate how index can improve the performance. Well there are lots of story to tell in the session, and I will be opening this session with the beautiful script of Botticelli’s Birth of Venus created by Michael J. Swart. I will also demonstrate few real life scenario where I will be talking about Spatial Database and its usage. Do not miss this session. At the end of session there will be book awarded to best participant. My session details: Session 3: Developing with SQL Server Spatial and Deep Dive into Spatial Indexing Date: April 14, 2010 Time: 5:00pm-6:00pm Microsoft SQL Server 2008 delivers new spatial data types that enable you to consume, use, and extend location-based data through spatial-enabled applications. Attend this session to learn how to use spatial functionality in next version of SQL Server to build and optimize spatial queries. This session outlines the new geography data type to store geodetic spatial data and perform operations on it, use the new geometry data type to store planar spatial data and perform operations on it, take advantage of new spatial indexes for high performance queries, use the new spatial results tab to quickly and easily view spatial query results directly from within Management Studio, extend spatial data capabilities by building or integrating location-enabled applications through support for spatial standards and specifications and much more. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Index, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL, Technology Tagged: Spatial Database

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• SQL SERVER – SOS_SCHEDULER_YIELD – Wait Type – Day 8 of 28

  - by pinaldave

  This is a very interesting wait type and quite often seen as one of the top wait types. Let us discuss this today. From Book On-Line: Occurs when a task voluntarily yields the scheduler for other tasks to execute. During this wait the task is waiting for its quantum to be renewed. SOS_SCHEDULER_YIELD Explanation: SQL Server has multiple threads, and the basic working methodology for SQL Server is that SQL Server does not let any “runnable” thread to starve. Now let us assume SQL Server OS is very busy running threads on all the scheduler. There are always new threads coming up which are ready to run (in other words, runnable). Thread management of the SQL Server is decided by SQL Server and not the operating system. SQL Server runs on non-preemptive mode most of the time, meaning the threads are co-operative and can let other threads to run from time to time by yielding itself. When any thread yields itself for another thread, it creates this wait. If there are more threads, it clearly indicates that the CPU is under pressure. You can fun the following DMV to see how many runnable task counts there are in your system. SELECT scheduler_id, current_tasks_count, runnable_tasks_count, work_queue_count, pending_disk_io_count FROM sys.dm_os_schedulers WHERE scheduler_id < 255 GO If you notice a two-digit number in runnable_tasks_count continuously for long time (not once in a while), you will know that there is CPU pressure. The two-digit number is usually considered as a bad thing; you can read the description of the above DMV over here. Additionally, there are several other counters (%Processor Time and other processor related counters), through which you can refer to so you can validate CPU pressure along with the method explained above. Reducing SOS_SCHEDULER_YIELD wait: This is the trickiest part of this procedure. As discussed, this particular wait type relates to CPU pressure. Increasing more CPU is the solution in simple terms; however, it is not easy to implement this solution. There are other things that you can consider when this wait type is very high. Here is the query where you can find the most expensive query related to CPU from the cache Note: The query that used lots of resources but is not cached will not be caught here. SELECT SUBSTRING(qt.TEXT, (qs.statement_start_offset/2)+1, ((CASE qs.statement_end_offset WHEN -1 THEN DATALENGTH(qt.TEXT) ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)+1), qs.execution_count, qs.total_logical_reads, qs.last_logical_reads, qs.total_logical_writes, qs.last_logical_writes, qs.total_worker_time, qs.last_worker_time, qs.total_elapsed_time/1000000 total_elapsed_time_in_S, qs.last_elapsed_time/1000000 last_elapsed_time_in_S, qs.last_execution_time, qp.query_plan FROM sys.dm_exec_query_stats qs CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) qt CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp ORDER BY qs.total_worker_time DESC -- CPU time You can find the most expensive queries that are utilizing lots of CPU (from the cache) and you can tune them accordingly. Moreover, you can find the longest running query and attempt to tune them if there is any processor offending code. Additionally, pay attention to total_worker_time because if that is also consistently higher, then  the CPU under too much pressure. You can also check perfmon counters of compilations as they tend to use good amount of CPU. Index rebuild is also a CPU intensive process but we should consider that main cause for this query because that is indeed needed on high transactions OLTP system utilized to reduce fragmentations. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All of the discussions of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• SQL SERVER – Error: Fix – Msg 208 – Invalid object name ‘dbo.backupset’ – Invalid object name ‘dbo.backupfile’

  - by pinaldave

  Just a day before I got a very interesting email. Here is the email (modified a bit to make it relevant to this blog post). “Pinal, We are facing a very strange issue. One of our query  related to backup files and backup set has stopped working suddenly in SSMS. It works fine in application where we have and in the stored procedure but when we have it in our SSMS it gives following error. Msg 208, Level 16, State 1, Line 1 Invalid object name ‘dbo.backupfile’. Here are our queries which we are trying to execute. SELECT name, database_name, backup_size, TYPE, compatibility_level, backup_set_id FROM dbo.backupset; SELECT logical_name, backup_size, file_type FROM dbo.backupfile; This query gives us details related to backupset and backup files when the backup was taken.” When I receive this kind of email, usually I have no answers directly. The claim that it works in stored procedure and in application but not in SSMS gives me no real data. I have requested him to very first check following two things: If he is connected to correct server? His answer was yes. If he has enough permissions? His answer was he was logged in as an admin. This means there was something more to it and I requested him to send me a screenshot of the his SSMS. He promptly sends that to me and as soon as I receive the screen shot I knew what was going on. Before I say anything take a look at the screenshot yourself and see if you can figure out why his queries are not working in SSMS. Just to make your life a bit easy, I have already given a hint in the image. The answer is very simple, the context of the database is master database. To execute above two queries the context of the database has to be msdb. Tables backupset and backupfile belong to the database msdb only. Here are two workaround or solution to above problem: 1) Change context to MSDB Above two queries when they will run as following they will not error out and will give the accurate desired result. USE msdb GO SELECT name, database_name, backup_size, TYPE, compatibility_level, backup_set_id FROM dbo.backupset; SELECT logical_name, backup_size, file_type FROM dbo.backupfile; 2) Prefix the query with msdb There are cases above script used in stored procedure or part of big query, it is not possible to change the context of the whole query to any specific database. Use three part naming convention and prefix them with msdb. SELECT name, database_name, backup_size, TYPE, compatibility_level, backup_set_id FROM msdb.dbo.backupset; SELECT logical_name, backup_size, file_type FROM msdb.dbo.backupfile; Very simple solution but sometime keeps people wondering for an answer. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Transcript of Learning SQL Server Performance: Indexing Basics – Interview of Vinod Kumar by Pinal Dave

  - by pinaldave

  Recently I just wrote a blog post on about Learning SQL Server Performance: Indexing Basics and I received lots of request that if we can share some insight into the course. Here is 200 seconds interview of Vinod Kumar I took right after completing the course. We have few free codes to watch the course, please your comment at http://facebook.com/SQLAuth and we will few of first ones, we will send the code. There are many people who said they would like to read the transcript of the video. Here I have generated the same. Pinal: Vinod, we recently released this course, SQL Server Indexing. It is about performance tuning. So tell me – how do indexes help performance? Vinod: I think what happens in the industry when it comes to performance is that developers and DBAs look at indexes first.  So that’s the first step for any performance tuning exercise, indexing is one of the most critical aspects and it is important to learn it the right way. Pinal: Correct. So what you mean to say is that if you know indexing you can pretty much tune any server and query. Vinod: So I might contradict my false statement now. Indexing is usually a stepping stone but it does not lead you to the end. But it’s good to start with indexing and there are lots of nuances to indexing that you need to understand, like how SQL uses indexing and how performance can improve because of the strategies that you have made. Pinal: But now I’m confused. First you said indexes are good, and then you said that indexes can degrade your performance.  So what is this course about?  I mean how does this course really make an impact? Vinod: Ok -so from the course perspective, what we are trying to do is give you a capsule which gives you a good start. Every journey needs a beginning, you need that first step.  This course is that first step in understanding. This is the most basic, fundamental course that we have tried to attack. This is the fundamentals of indexing, some of the key things that you must know about indexing.   Some of the basics of indexing are lesser known and so I think this course is geared towards each and every one of you out there who wants to understand little bit more about indexing. Pinal: So what I understand is that if I enrolled in this course I will have a minimum understanding about indexing when dealing with performance tuning.  Right? Vinod: Exactly. In this course is we have tried to give you a nice summary. We are talking about clustered indexing, non clustered indexing, too many indexes, too few indexes, over indexing, under indexing, duplicate indexing, columns tune indexing, with SQL Server 2012. There’s lot’s to learn. Pinal: You can see the URL [http://bit.ly/sql-index] of the course on the screen. Go ahead, attend, and let us know what you think about it. Thank you. Vinod: Thank you. 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, SQLServer, T SQL, Technology, Video

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• SQL SERVER – Data Pages in Buffer Pool – Data Stored in Memory Cache

  - by pinaldave

  This will drop all the clean buffers so we will be able to start again from there. Now, run the following script and check the execution plan of the query. Have you ever wondered what types of data are there in your cache? During SQL Server Trainings, I am usually asked if there is any way one can know how much data in a table is stored in the memory cache? The more detailed question I usually get is if there are multiple indexes on table (and used in a query), were the data of the single table stored multiple times in the memory cache or only for a single time? Here is a query you can run to figure out what kind of data is stored in the cache. USE AdventureWorks GO SELECT COUNT(*) AS cached_pages_count, name AS BaseTableName, IndexName, IndexTypeDesc FROM sys.dm_os_buffer_descriptors AS bd INNER JOIN ( SELECT s_obj.name, s_obj.index_id, s_obj.allocation_unit_id, s_obj.OBJECT_ID, i.name IndexName, i.type_desc IndexTypeDesc FROM ( SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id ,allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.hobt_id AND (au.type = 1 OR au.type = 3) UNION ALL SELECT OBJECT_NAME(OBJECT_ID) AS name, index_id, allocation_unit_id, OBJECT_ID FROM sys.allocation_units AS au INNER JOIN sys.partitions AS p ON au.container_id = p.partition_id AND au.type = 2 ) AS s_obj LEFT JOIN sys.indexes i ON i.index_id = s_obj.index_id AND i.OBJECT_ID = s_obj.OBJECT_ID ) AS obj ON bd.allocation_unit_id = obj.allocation_unit_id WHERE database_id = DB_ID() GROUP BY name, index_id, IndexName, IndexTypeDesc ORDER BY cached_pages_count DESC; GO Now let us run the query above and observe the output of the same. We can see in the above query that there are four columns. Cached_Pages_Count lists the pages cached in the memory. BaseTableName lists the original base table from which data pages are cached. IndexName lists the name of the index from which pages are cached. IndexTypeDesc lists the type of index. Now, let us do one more experience here. Please note that you should not run this test on a production server as it can extremely reduce the performance of the database. DBCC DROPCLEANBUFFERS This will drop all the clean buffers and we will be able to start again from there. Now run following script and check the execution plan for the same. USE AdventureWorks GO SELECT UnitPrice, ModifiedDate FROM Sales.SalesOrderDetail WHERE SalesOrderDetailID BETWEEN 1 AND 100 GO The execution plans contain the usage of two different indexes. Now, let us run the script that checks the pages cached in SQL Server. It will give us the following output. It is clear from the Resultset that when more than one index is used, datapages related to both or all of the indexes are stored in Memory Cache separately. Let me know what you think of this article. I had a great pleasure while writing this article because I was able to write on this subject, which I like the most. In the next article, we will exactly see what data are cached and those that are not cached, using a few undocumented commands. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: SQL DMV

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• SQL SERVER – #TechEdIn – Presenting Tomorrow on Speed Up! – Parallel Processes and Unparalleled Performance at TechEd India 2012

  - by pinaldave

  Performance tuning is always a very hot topic when it is about SQL Server. SQL Server Performance Tuning is a very challenging subject that requires expertise in Database Administration and Database Development. I always have enjoyed talking about SQL Server Performance tuning subject. However, in India, it’s actually the very first time someone is presenting on this interesting subject, so this time I had the biggest challenge to present this session. Frequently enough, we get these two kind of questions: How to turn off parallelism as it is reducing performance? How to turn on parallelism as I want more performance? The reality is that not everyone knows what exactly is needed by their system. In this session, I have attempted to answer this very question. I’ve decided to provide a balanced view but stay away from theory, which leads us to say “It depends”. The session will have a clear message about this towards its end. Deck Details Slides: 45+ Demos: 7+ Bonus Quiz: 5 Images: 10+ Session delivery time: 52 Mins + 8 Mins of Q & A I have presented this session a couple of times to my friends and so far have received good feedback. Oftentimes, when people hear that I am going to present 45 slides, they all say it is too much to cover. However, when I am done with the session the usual reaction is that I truly gave justice to those slides. Action Item Here are a few of the action items for all of those who are going to attend this session: If you want to attend the session, just come early. There’s a good chance that you may not get a seat because right before me, there is a session from SQL Guru Vinod Kumar. He performs a powerful delivery of million concepts in just a little time. Quiz. I will be asking few questions during the session as well as before the session starts. If you get the correct answer, I will give unique learning material for you. You may not want to miss this learning opportunity at any cosst. Session Details Title: Speed Up! – Parallel Processes and Unparalleled Performance (Add to Calendar) Abstract: “More CPU, More Performance” – A  very common understanding is that usage of multiple CPUs can improve the performance of the query. To get a maximum performance out of any query, one has to master various aspects of the parallel processes. In this deep-dive session, we will explore this complex subject with a very simple interactive demo. Attendees will walk away with proper understanding of CX_PACKET wait types, MAXDOP, parallelism threshold and various other concepts. Date and Time: March 23, 2012, 12:15 to 13:15 Location: Hotel Lalit Ashok - Kumara Krupa High Grounds, Bengaluru – 560001, Karnataka, India. Add to Calendar Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• Intel Extreme Tuning utility options are greyed

  - by Abhishek Sha

  I'm having a ASUS K55VM with Intel Core i7 3610QM (IvyBridge) with a NVIDIA GT630M. I'm trying to operate the Intel XTU, but as you can see in the screenshot, all the options are greyed out. Can you please help with this situation. Another are is the CPU Throttling (Intel SpeedStep) which is always shown as 0%. But in the Intel Turbo Monitor, the Speed keeps dynamically changing. Then why is the CPU Throttling always at 0%?:

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• Solaris TCP stack tuning

  - by disserman

  We have a large web project (about 2-3k requests per second), using haproxy (http://haproxy.1wt.eu/) as a frontend and load balancer between the java application servers. The frontend (haproxy) is running on Linux but we are going to migrate it to the Solaris 10 as all our other servers are running under Solaris. After switching a traffic I see the two things: a) the web site became loading slower (5-10 seconds with images in comparison to 2-3 seconds on Linux) b) sometimes haproxy fails to perform a "lifecheck" (get a special web page and analyze http response code) due to the socket timeout. After switching traffic back to Linux everything is okay. I've tried to tune all params I found in /dev/tcp but no progress. I believe the problem is in some open socket limitations. If someone can point me to the answer, I would be greatly appreciated. p.s. haproxy is running under Xen DomU on Linux (Kernel 2.6.18, Debian 5), under zone on Solaris (10 u8). the only thing we did on Linux is increasing of ip_conntrack_max (I believe Solaris option tcp_conn_req_max_q is the equivalent).

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• Tuning Linux IP routing parameters -- secret_interval and tcp_mem

  - by Jeff Atwood

  We had a little failover problem with one of our HAProxy VMs today. When we dug into it, we found this: Jan 26 07:41:45 haproxy2 kernel: [226818.070059] __ratelimit: 10 callbacks suppressed Jan 26 07:41:45 haproxy2 kernel: [226818.070064] Out of socket memory Jan 26 07:41:47 haproxy2 kernel: [226819.560048] Out of socket memory Jan 26 07:41:49 haproxy2 kernel: [226822.030044] Out of socket memory Which, per this link, apparently has to do with low default settings for net.ipv4.tcp_mem. So we increased them by 4x from their defaults (this is Ubuntu Server, not sure if the Linux flavor matters): current values are: 45984 61312 91968 new values are: 183936 245248 367872 After that, we started seeing a bizarre error message: Jan 26 08:18:49 haproxy1 kernel: [ 2291.579726] Route hash chain too long! Jan 26 08:18:49 haproxy1 kernel: [ 2291.579732] Adjust your secret_interval! Shh.. it's a secret!! This apparently has to do with /proc/sys/net/ipv4/route/secret_interval which defaults to 600 and controls periodic flushing of the route cache The secret_interval instructs the kernel how often to blow away ALL route hash entries regardless of how new/old they are. In our environment this is generally bad. The CPU will be busy rebuilding thousands of entries per second every time the cache is cleared. However we set this to run once a day to keep memory leaks at bay (though we've never had one). While we are happy to reduce this, it seems odd to recommend dropping the entire route cache at regular intervals, rather than simply pushing old values out of the route cache faster. After some investigation, we found /proc/sys/net/ipv4/route/gc_elasticity which seems to be a better option for keeping the route table size in check: gc_elasticity can best be described as the average bucket depth the kernel will accept before it starts expiring route hash entries. This will help maintain the upper limit of active routes. We adjusted elasticity from 8 to 4, in the hopes of the route cache pruning itself more aggressively. The secret_interval does not feel correct to us. But there are a bunch of settings and it's unclear which are really the right way to go here. /proc/sys/net/ipv4/route/gc_elasticity (8) /proc/sys/net/ipv4/route/gc_interval (60) /proc/sys/net/ipv4/route/gc_min_interval (0) /proc/sys/net/ipv4/route/gc_timeout (300) /proc/sys/net/ipv4/route/secret_interval (600) /proc/sys/net/ipv4/route/gc_thresh (?) rhash_entries (kernel parameter, default unknown?) We don't want to make the Linux routing worse, so we're kind of afraid to mess with some of these settings. Can anyone advise which routing parameters are best to tune, for a high traffic HAProxy instance?

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• Tuning Windows 7 for use in a VM

  - by intuited

  I'm running Windows 7 in a VirtualBox Virtual Machine, and would like to make it run in a more streamlined fashion. I'll be using the install primarily for testing web apps, and have no need for it to run quickly. I would like it to run with minimal memory requirements, and with minimal changes to its virtual hard drive's contents. Changes to the hard drive contents, for example the paging file, result in larger snapshot sizes. Another recent post of mine seems to be related to this issue, but does not directly address issues with Windows. One concern that I have is that Windows seems to be using 17% of its paging file even with over 900MB of memory marked "Standby" or "Free". My uneducated guess is that this is being used to store indexes or some other data that helps to speed up the system but is not really necessary. I'm also wondering if it's normal for Windows to use over 500 MB of "In Use" memory with no apps running. Will this amount decrease if I reduce the amount of "installed" memory in the VM? What steps can I take to reduce the system's memory footprint without incurring an increase in paging file usage?

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• postgres memory allocation tuning 2

  - by pstanton

  i've got a Ubuntu Linux system with 12Gb memory most of which (at least 10Gb) can be allocated solely to postgres. the system also has a 6 disk 15k SCSI RAID 10 setup. The process i'm trying to optimise is twofold. firstly a single threaded, single connection will do many inserts into 2-4 tables linked by foreign key. secondly many different complex queries are run against the resulting data, using group by extensively. this part especially needs to be optimised. i have four of these processes running at once in order to make use of the quad core CPU, therefore there will generally be no more than 5 concurrent connections (1 spare for admin tasks). what configuration changes to the default Postgres config would you recommend? I'm looking for the optimum values for things like work_mem, shared_buffers etc. relevant doco thanks!

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• Debian tuning for increasing read/write buffer.

  - by Claudiu

  Is there a way to modify Debian settings so the memory could be used more for disk read/write caching ? I am already using RAID 0 but thats not enough for multiple users, and the disk is almost struggled. Torrents use the disk very much and rTorrent doesn't have cache settings.

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• Fine-tuning a LNMP stack

  - by Norman

  I'm in the process of setting up a server with 4GB RAM and 2 CPUs. The stack will be CentOS + NGINX + MySQL + PHP (with APC) and spawn-fcgi. It will be used to serve 10 Wordpress blogs, 3 of which receive about 20,000 hits per day. Each Wordpress instance is equipped with the W3 TotalCache. I have a few variables to play with: NGINX (How many worker_processes, worker_connections, etc) PHP (What parameters in php.ini should I change? What about apc?) Spawn-fcgi (Right now I have 6 php-cgi spawned. How many of them should I have?) I realize it's hard to tell without testing, but if you could please provide me with some ballpark numbers, that would be helpful too.

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• Reccomendation for tuning 100's of Sql Databases

  - by wayne

  Hi, I'm running several sql servers, each running a few hundred multi gig databases for customers. They are all setup homogeneously as far as the schemas are concerned, however customer usages of the data differ quite alot from database to database. What would be the best way to auto-index / profile / tune this large amount of databases? As there are atleast 600 or more catalogs i cant have someone manually profile, and index as required by each databases usage patterns. I'm currently running SQL 2005 but will be moving to 2008, so solutions that work with either are fine!

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• Exchange Server 2007 message tracking log tuning ?

  - by Albert Widjaja

  Hi All, what is the best practice if I want to have a retention of let say 6 months ? I'm confused which parameter that is should/can be changes. Get-ExchangeServer | where {$_.isHubTransportServer -eq $true} | Get-TransportServer | select Name, *MessageTracking* | ft -AutoSize Name MessageTrackingLogEnabled MessageTrackingLogMaxAge MessageTrackingLogMaxDirectorySize MessageTrackingLogMaxFileSize MessageTrackingLogPat h ---- ------------------------- ------------------------ ---------------------------------- ----------------------------- --------------------- ExHTServer1 True 20.00:00:00 250MB 10MB D:\Program Files\M... ExHTServer2 True 20.00:00:00 250MB 10MB D:\Program Files\M... ExHTServer3 True 20.00:00:00 250MB 10MB D:\Program Files\M... Thanks, Albert

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• memory tuning with rails/unicorn running on ubuntu

  - by user970193

  I am running unicorn on Ubuntu 11, Rails 3.0, and Ruby 1.8.7. It is an 8 core ec2 box, and I am running 15 workers. CPU never seems to get pinned, and I seem to be handling requests pretty nicely. My question concerns memory usage, and what concerns I should have with what I am seeing. (if any) Here is the scenario: Under constant load (about 15 reqs/sec coming in from nginx), over the course of an hour, each server in the 3 server cluster loses about 100MB / hour. This is a linear slope for about 6 hours, then it appears to level out, but still maybe appear to lose about 10MB/hour. If I drop my page caches using the linux command echo 1 /proc/sys/vm/drop_caches, the available free memory shoots back up to what it was when I started the unicorns, and the memory loss pattern begins again over the hours. Before: total used free shared buffers cached Mem: 7130244 5005376 2124868 0 113628 422856 -/+ buffers/cache: 4468892 2661352 Swap: 33554428 0 33554428 After: total used free shared buffers cached Mem: 7130244 4467144 2663100 0 228 11172 -/+ buffers/cache: 4455744 2674500 Swap: 33554428 0 33554428 My Ruby code does use memoizations and I'm assuming Ruby/Rails/Unicorn is keeping its own caches... what I'm wondering is should I be worried about this behaviour? FWIW, my Unicorn config: worker_processes 15 listen "#{CAPISTRANO_ROOT}/shared/pids/unicorn_socket", :backlog = 1024 listen 8080, :tcp_nopush = true timeout 180 pid "#{CAPISTRANO_ROOT}/shared/pids/unicorn.pid" GC.respond_to?(:copy_on_write_friendly=) and GC.copy_on_write_friendly = true before_fork do |server, worker| STDERR.puts "XXXXXXXXXXXXXXXXXXX BEFORE FORK" print_gemfile_location defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect! defined?(Resque) and Resque.redis.client.disconnect old_pid = "#{CAPISTRANO_ROOT}/shared/pids/unicorn.pid.oldbin" if File.exists?(old_pid) && server.pid != old_pid begin Process.kill("QUIT", File.read(old_pid).to_i) rescue Errno::ENOENT, Errno::ESRCH # already killed end end File.open("#{CAPISTRANO_ROOT}/shared/pids/unicorn.pid.ok", "w"){|f| f.print($$.to_s)} end after_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection defined?(Resque) and Resque.redis.client.connect end Is there a need to experiment enforcing more stringent garbage collection using OobGC (http://unicorn.bogomips.org/Unicorn/OobGC.html)? Or is this just normal behaviour, and when/as the system needs more memory, it will empty the caches by itself, without me manually running that cache command? Basically, is this normal, expected behaviour? tia

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• Solaris TCP/IP performance tuning

  - by Andy Faibishenko

  I am trying to tune a high message traffic system running on Solaris. The architecture is a large number (600) of clients which connect via TCP to a big Solaris server and then send/receive relatively small messages (.5 to 1K payload) at high rates. The goal is to minimize the latency of each message processed. I suspect that the TCP stack of the server is getting overwhelmed by all the traffic. What are some commands/metrics that I can use to confirm this, and in case this is true, what is the best way to alleviate this bottleneck? PS I posted this on StackOverflow originally. One person suggested snoop and dtrace. dtrace seems pretty general - are there any additional pointers on how to use it to diagnose TCP issues?

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• Tuning OpenVZ Containers to work better with Java?

  - by Daniel

  I have a 8 GB RAM Server (Dedicated) and currently have KVM Virtual Machines running on there (successfully) however i'm considering moving to OpenVZ as KVM seems a bit overkill with a lot of overhead for what i use it for. In the past i have used OpenVZ Containers, hosted by myself and from other providers and Java doesn't seem to work well with them.. One example is that if i give a container 2 GB RAM ( No burst) (with or without vswap doesn't matter) a java instance can only be tuned to use at very most 1500 MB of that RAM (-Xmx, -Xms). Ideally, i wish to be able to create "Mini" containers with about 256MB, 512MB, 768 RAM and run some java instances in them. My question is: I'm trying to find an ideal way to tune a OpenVZ container configuration to work better with Java memory. Please, don't suggest anything related to Java settings, i'm looking for OpenVZ specific answers.. Though i welcome any suggestion if you feel it may help me. Much Appreciated, Daniel

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• recyle application pool,Warm up scripts-Performance tuning in Sharepoint WCM site

  - by joel14141

  I was trying to tune WCM public facing site we have in Sharepoint . I have following doubts By default application pools are set to recycle themselves at 2 am in night and because of that we need warm up scripts . But As I was googling on this topic I found mixed reactions on this some MVP are saying its not advisable to recycle application pool daily and some say otherwise so I am confused. Because if I am not doing recycling application pool then I don't hv to use warmup scripts . But as my site is public facing and its all around the globe so is it advisable that I should recycle it daily as it will affect the performance of my site even though I would run warm up scripts once I don't think so it wud be as good as it should be ....Any advice on that?

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• recyle application pool,Warm up scripts-Performance tuning in Sharepoint WCM site

  - by joel14141

  I was trying to tune WCM public facing site we have in Sharepoint . I have following doubts By default application pools are set to recycle themselves at 2 am in night and because of that we need warm up scripts . But As I was googling on this topic I found mixed reactions on this some MVP are saying its not advisable to recycle application pool daily and some say otherwise so I am confused. Because if I am not doing recycling application pool then I don't hv to use warmup scripts . But as my site is public facing and its all around the globe so is it advisable that I should recycle it daily as it will affect the performance of my site even though I would run warm up scripts once I don't think so it wud be as good as it should be ....Any advice on that?

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• Tuning MySQL to consume less memory

  - by Alex

  I have a VM which has 2GB Ram, (full specs) And I am setting up a site which has one table in particular with over a million records. There's little or no usage of this particular database (perhaps once or twice a day) but simply running mysql grinds the whole server to a halt. I've looked through the top results but nothing is really denting the CPU however the memory seems to be the issue. The site isnt even live of taking requests yet. the memory situation looks like this: # free -m total used free shared buffers cached Mem: 2006 1880 126 0 3 53 -/+ buffers/cache: 1823 183 Swap: 2047 345 1702 Are there any good pointers to tune mysql to stop hogging the system memory? Thanks very much EDIT: (requested by 8bit): http://tny.cz/b41a0b12

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• Reccomendation for tuning 100's of SQL Databases

  - by wayne

  I'm running several SQL servers, each running a few hundred multi-gig databases for customers. They are all setup homogeneously as far as the schemas are concerned, however customer usages of the data differ quite a lot from database to database. What would be the best way to auto-index/profile/tune this large amount of databases? As there are at least 600 or more catalogs I cant have someone manually profile, and index as required by each databases usage patterns. I'm currently running SQL 2005 but will be moving to 2008, so solutions that work with either are fine.

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• SQL SERVER – Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012

  - by pinaldave

  This blog post is written in response to the T-SQL Tuesday post of Prox ‘n’ Funx. This is a very interesting subject. By the way Brad Schulz is my favorite guy when it is about blogging. I respect him as well learn a lot from him. Everybody is writing something new his subject, I decided to start SQL Server 2012 analytic functions series. SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Let us fun following query. USE AdventureWorks GO SELECT SalesOrderID, OrderQty, CUME_DIST() OVER(ORDER BY SalesOrderID) AS CDist FROM Sales.SalesOrderDetail WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY CDist DESC GO Above query will give us following result. Now let us understand what is the formula behind CUME_DIST and why the values in SalesOrderID = 43670 are 1. Let us take more example and be clear about why the values in SalesOrderID = 43667 are 0.5. Now let us enhence the same example and use PARTITION BY into the OVER clause and see the results. Run following query in SQL Server 2012. USE AdventureWorks GO SELECT SalesOrderID, OrderQty, ProductID, CUME_DIST() OVER(PARTITION BY SalesOrderID ORDER BY ProductID ) AS CDist FROM Sales.SalesOrderDetail s WHERE SalesOrderID IN (43670, 43669, 43667, 43663) ORDER BY s.SalesOrderID DESC, CDist DESC GO Now let us see the result of this query. We are have changed the ORDER BY clause as well partitioning by SalesOrderID. You can see that CUME_DIST() function provides us different results. Additionally now we see value 1 multiple times. As we are using partitioning for each group of SalesOrderID we get the CUME_DIST() value. CUME_DIST() was long awaited Analytical function and I am glad to see it in SQL Server 2012. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• SQL SERVER – Validating Spatial Object with IsValidDetailed Function

  - by pinaldave

  What do you prefer – error or warning indicating error may happen with the reason for the error. While writing the previous statement I remember the movie “Minory Report”. This blog post is not about minority report but I will still cover the concept in a single statement “Let us predict the future and prevent the crime which is about to happen in future”. (Please feel free to correct me if I am wrong about the movie concept, I really do not want to hurt your sentiment if you are dedicated fan). Let us switch to the SQL Server world. Spatial data types are interesting concepts. I love writing about spatial data types because it allows me to be creative with shapes (just like toddlers). When working with Spatial Datatypes it is all good when the spatial object works fine. However, when the spatial object has issue or it is created with invalid coordinates it used to give a simple error that there is an issue with the object but did not provide much information. This made it very difficult to debug. If this spatial object was used in the big procedure and while this big procedural error out because of the invalid spatial object, it is indeed very difficult to debug it. I always wished that the more information provided regarding what is the problem with spatial datatype. SQL Server 2012 has introduced the new function IsValidDetailed(). This function has made my life very easy. In simple words this function will check if the spatial object passed is valid or not. If it is valid it will give information that it is valid. If the spatial object is not valid it will return the answer that it is not valid and the reason for the same. This makes it very easy to debug the issue and make the necessary correction. DECLARE @p GEOMETRY = 'Polygon((2 2, 6 6, 4 2, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'Polygon((2 2, 4 4, 4 2, 2 3, 2 2))' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'CIRCULARSTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'CIRCULARSTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO DECLARE @p GEOMETRY = 'LINESTRING(2 2, 4 4, 0 0)' SELECT @p.IsValidDetailed() GO Here is the resultset of the above query. You can see any valid query and some invalid query. If the query is invalid it also demonstrates the reason along with the error message. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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• SQL SERVER – Fix: Error: 147 An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference

  - by pinaldave

  Everybody was beginner once and I always like to get involved in the questions from beginners. There is a big difference between the question from beginner and question from advanced user. I have noticed that if an advanced user gets an error, they usually need just a small hint to resolve the problem. However, when a beginner gets error he sometimes sits on the error for a long time as he/she has no idea about how to solve the problem as well have no idea regarding what is the capability of the product. I recently received a very novice level question. When I received the problem I quickly see how the user was stuck. When I replied him with the solution, he wrote a long email explaining how he was not able to solve the problem. He thanked multiple times in the email. This whole thing inspired me to write this quick blog post. I have modified the user’s question to match the code with AdventureWorks as well simplified so it contains the core content which I wanted to discuss. Problem Statement: Find all the details of SalesOrderHeaders for the latest ShipDate. He comes up with following T-SQL Query: SELECT * FROM [Sales].[SalesOrderHeader] WHERE ShipDate = MAX(ShipDate) GO When he executed above script it gave him following error: Msg 147, Level 15, State 1, Line 3 An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference. He was not able to resolve this problem, even though the solution was given in the query description itself. Due to lack of experience he came up with another version of above query based on the error message. SELECT * FROM [Sales].[SalesOrderHeader] HAVING ShipDate = MAX(ShipDate) GO When he ran above query it produced another error. Msg 8121, Level 16, State 1, Line 3 Column ‘Sales.SalesOrderHeader.ShipDate’ is invalid in the HAVING clause because it is not contained in either an aggregate function or the GROUP BY clause. What he wanted actually was the SalesOrderHeader all the Sales shipped on the last day. Based on the problem statement what the right solution is as following, which does not generate error. SELECT * FROM [Sales].[SalesOrderHeader] WHERE ShipDate = (SELECT MAX(ShipDate) FROM [Sales].[SalesOrderHeader]) Well, that’s it! Very simple. With SQL Server there are always multiple solution to a single problem. Is there any other solution available to the problem stated? Please share in the comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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