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  • "Oracle", "Sybase", "SQL Server" vs just "SQL/JDBC" in the CV

    - by bobah
    How would you define a testable measure of the expertise that, if you're honest with yourself, lets you write in your CV words "Oracle", "Sybase", or "SQL Server" and not just "Relational Databases, SQL, JDBC" in your software developer's CV? What every XXX-developer (XXX - a vendor name) should know? The question is similar to http://stackoverflow.com/questions/2119859/questions-every-good-database-sql-developer-should-be-able-to-answer but is vendor-specific. Below is a start of the list as an example, demonstrate what kind of answers I am hoping to get. If you are expert in X then you know that Y (X - Y below): Sybase/SQL Server - they are very similar, Sybase is much more expensive Sybase/SQL Server - for Java you can use either native Sybase/JSQLDB driver or jTDS that is using TDS protocol and can connect to SQL Server as well, TDS traffic can be dumped and analyzed with hexdump command Sybase/SQL Server - for C++ you can use FreeTDS to connect to any, for Perl - same Sybase/SQL Server - a query can return multiple result sets and return codes, all need to be processes otherwise errors can happen Sybase/SQL Server - sp_help, sp_helptext Sybase/SQL Server - your tables/views/procedures are under DBName/dbo/... Sybase - for C++ on Linux you can use Sybase client API to connect (at least until recently) SQL Server - JDBC driver has a configurable transparent failover capability Oracle - for C++ Linux one can use OTLv4 that is a very powerful yet lightweight wrapper around Oracle client API Oracle compilation (contributors: ammoQ) PLSQL Java Stored Procedures '' is null Hierarchical Query Analytic Functions Oracle Text

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  • SQL Server 2008 R2 still requires a trace flag for Lock Pages in Memory

    - by AaronBertrand
    Almost two years ago, I blogged that Lock Pages in Memory was finally available to Standard Edition customers (Enterprise Edition customers had long been deemed smart enough to not abuse this feature). In addition to applying a cumulative update (2005 SP3 CU4 or 2008 SP1 CU2), in order to take advantage of LPIM, you also had to enable trace flag 845. Since the trace flag isn't documented for SQL Server 2008 R2, several of us in the community assumed that it was no longer required (since it was introduced...(read more)

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  • SQL Server 2008 R2 still requires a trace flag for Lock Pages in Memory

    - by AaronBertrand
    Almost two years ago, I blogged that Lock Pages in Memory was finally available to Standard Edition customers (Enterprise Edition customers had long been deemed smart enough to not abuse this feature). In addition to applying a cumulative update (2005 SP3 CU4 or 2008 SP1 CU2), in order to take advantage of LPIM, you also had to enable trace flag 845. Since the trace flag isn't documented for SQL Server 2008 R2, several of us in the community assumed that it was no longer required (since it was introduced...(read more)

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  • How In-Memory Database Objects Affect Database Design: The Conceptual Model

    - by drsql
    After a rather long break in the action to get through some heavy tech editing work (paid work before blogging, I always say!) it is time to start working on this presentation about In-Memory Databases. I have been trying to decide on the scope of the demo code in the back of my head, and I have added more and taken away bits and pieces over time trying to find the balance of "enough" complexity to show data integrity issues and joins, but not so much that we get lost in the process of trying to...(read more)

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  • How In-Memory Database Objects Affect Database Design: The Conceptual Model

    - by drsql
    After a rather long break in the action to get through some heavy tech editing work (paid work before blogging, I always say!) it is time to start working on this presentation about In-Memory Databases. I have been trying to decide on the scope of the demo code in the back of my head, and I have added more and taken away bits and pieces over time trying to find the balance of "enough" complexity to show data integrity issues and joins, but not so much that we get lost in the process of trying to...(read more)

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  • Replication: SQL Server 2008 Publisher with SQL Server Express 2005 Subscriber

    - by Jeremy
    Here is the setup: SQL Server 2008 Enterprise Server with a Merge Publication. SQL Server 2005 Express with pull subscription. There is no web or ftp setup. This is direct merge replication. Using the RMO objects from C#, I get a "class cannot be found." COM Error when accessing the MergePullSubscription.SynchronizationAgent property. I've tried with both the 2008 RMO dll's (version 10 dll's) and the 2005 RMO dll's (version 9 dll's). When trying to use replmerge.exe, I get the following: 2010-04-10 04:12:05.263 Microsoft SQL Server Merge Agent 9.00.1399.06 2010-04-10 04:12:05.294 Copyright (c) 2000 Microsoft Corporation 2010-04-10 04:12:05.294 2010-04-10 04:12:05.294 The timestamps prepended to the output lines are express ed in terms of UTC time. 2010-04-10 04:12:05.294 User-specified agent parameter values: -Publisher SUN -PublisherDB PRIMROSE -PublisherSecurityMode 1 -Publication PRIMROSE -Distributor SUN -DistributorSecurityMode 1 -Subscriber PVILLE\SQLEXPRESS -SubscriberSecurityMode 1 -SubscriberDB PRIMROSE -SubscriptionType 1 -DistributorLogin sa -DistributorPassword ********** -DistributorSecurityMode 0 -PublisherLogin sa -PublisherPassword ********** -PublisherSecurityMode 0 -SubscriberLogin sa -SubscriberPassword ********** -SubscriberSecurityMode 0 2010-04-10 04:12:05.325 Connecting to Subscriber 'PVILLE\SQLEXPRESS' 2010-04-10 04:12:05.481 Connecting to Distributor 'SUN' 2010-04-10 04:12:05.513 The version of SQL Server running at the Distributor(10. 0.2531.??????????????????) is not compatible with the version of SQL Server runn ing at the Subscriber(9.00.1399.???????L?L?LHL?L?L?L?,?). 2010-04-10 04:12:05.513 Category:NULL Source: Merge Process Number: -2147200979 Message: The version of SQL Server running at the Distributor(10.0.2531.???????? ??????????) is not compatible with the version of SQL Server running at the Subs criber(9.00.1399.???????L?L?LHL?L?L?L?,?). Any ideas?

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  • How to find number of memory accesses

    - by Sharat Chandra
    Can anybody tell me a unix command that can be used to find the number of memory accesses that took place in a given interval. vmstat, top and sar only give the amount of physical memory space occupied/available .. But do not give the number of memory of accesses in a given interval

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  • Oracle SQL Developer is for Oracle Database

    - by thatjeffsmith
    What is Oracle SQL Developer? Well, according to this document on OTN… What is SQL Developer? Date: May 2014 Oracle SQL Developer is the Oracle Database IDE. A free graphical user interface, Oracle SQL Developer allows database users and administrators to do their database tasks in fewer clicks and keystrokes. A productivity tool, SQL Developer’s main objective is to help the end user save time and maximize the return on investment in the Oracle Database technology stack. Ok, sounds pretty straightforward. Where does the confusion lie then? Some People Use SQL Developer to Connect to 3rd Party Databases SQL Developer allows you to register 3rd party database JDBC drivers. The 3rd party being a company OTHER than Oracle that makes a database product. You know who they are (SAP, MSFT, IBM, etc.) Registering 3rd party JDBC drivers in SQL Developer But maybe you don’t understand why we support these types of connections? It’s for one driving reason. To Help You Migrate to Oracle Database Yes, you get a worksheet and a tree to query and browse those systems. But, the real meat and bones there are around our migration projects and our translation scratch editor. At the end of the day, it’s there so you can move your data from say Sybase ASE to Oracle Database. On a side note, the migration technology was previously available in a separate application, the Migration Workbench. The technology and the awesome people behind it were folded into SQL Developer. So when asked what SQL Developer is, I say it’s the Database IDE and the official 3rd party database migration to Oracle platform. So anyways, when you ask for better support for another 3rd party provider, we deliver that support based on that business driver. If another 3rd party database jdbc driver is introduced, it’s because we have a lot of customers migrating from that platform. We’re not adding it to make it easier for you to work with SQL Server on your Mac. But, if you find that useful – that is cool. It’s just not why we’ve got the support for SQL Server connections in SQL Developer.

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  • T-SQL Dynamic SQL and Temp Tables

    - by George
    It looks like #temptables created using dynamic SQL via the EXECUTE string method have a different scope and can't be referenced by "fixed" SQLs in the same stored procedure. However, I can reference a temp table created by a dynamic SQL statement in a subsequence dynamic SQL but it seems that a stored procedure does not return a query result to a calling client unless the SQL is fixed. A simple 2 table scenario: I have 2 tables. Let's call them Orders and Items. Order has a Primary key of OrderId and Items has a Primary Key of ItemId. Items.OrderId is the foreign key to identify the parent Order. An Order can have 1 to n Items. I want to be able to provide a very flexible "query builder" type interface to the user to allow the user to select what Items he want to see. The filter criteria can be based on fields from the Items table and/or from the parent Order table. If an Item meets the filter condition including and condition on the parent Order if one exists, the Item should be return in the query as well as the parent Order. Usually, I suppose, most people would construct a join between the Item table and the parent Order tables. I would like to perform 2 separate queries instead. One to return all of the qualifying Items and the other to return all of the distinct parent Orders. The reason is two fold and you may or may not agree. The first reason is that I need to query all of the columns in the parent Order table and if I did a single query to join the Orders table to the Items table, I would be repoeating the Order information multiple times. Since there are typically a large number of items per Order, I'd like to avoid this because it would result in much more data being transfered to a fat client. Instead, as mentioned, I would like to return the two tables individually in a dataset and use the two tables within to populate a custom Order and child Items client objects. (I don't know enough about LINQ or Entity Framework yet. I build my objects by hand). The second reason I would like to return two tables instead of one is because I already have another procedure that returns all of the Items for a given OrderId along with the parent Order and I would like to use the same 2-table approach so that I could reuse the client code to populate my custom Order and Client objects from the 2 datatables returned. What I was hoping to do was this: Construct a dynamic SQL string on the Client which joins the orders table to the Items table and filters appropriate on each table as specified by the custom filter created on the Winform fat-client app. The SQL build on the client would have looked something like this: TempSQL = " INSERT INTO #ItemsToQuery OrderId, ItemsId FROM Orders, Items WHERE Orders.OrderID = Items.OrderId AND /* Some unpredictable Order filters go here */ AND /* Some unpredictable Items filters go here */ " Then, I would call a stored procedure, CREATE PROCEDURE GetItemsAndOrders(@tempSql as text) Execute (@tempSQL) --to create the #ItemsToQuery table SELECT * FROM Items WHERE Items.ItemId IN (SELECT ItemId FROM #ItemsToQuery) SELECT * FROM Orders WHERE Orders.OrderId IN (SELECT DISTINCT OrderId FROM #ItemsToQuery) The problem with this approach is that #ItemsToQuery table, since it was created by dynamic SQL, is inaccessible from the following 2 static SQLs and if I change the static SQLs to dynamic, no results are passed back to the fat client. 3 around come to mind but I'm look for a better one: 1) The first SQL could be performed by executing the dynamically constructed SQL from the client. The results could then be passed as a table to a modified version of the above stored procedure. I am familiar with passing table data as XML. If I did this, the stored proc could then insert the data into a temporary table using a static SQL that, because it was created by dynamic SQL, could then be queried without issue. (I could also investigate into passing the new Table type param instead of XML.) However, I would like to avoid passing up potentially large lists to a stored procedure. 2) I could perform all the queries from the client. The first would be something like this: SELECT Items.* FROM Orders, Items WHERE Order.OrderId = Items.OrderId AND (dynamic filter) SELECT Orders.* FROM Orders, Items WHERE Order.OrderId = Items.OrderId AND (dynamic filter) This still provides me with the ability to reuse my client sided object-population code because the Orders and Items continue to be returned in two different tables. I have a feeling to, that I might have some options using a Table data type within my stored proc, but that is also new to me and I would appreciate a little bit of spoon feeding on that one. If you even scanned this far in what I wrote, I am surprised, but if so, I woul dappreciate any of your thoughts on how to accomplish this best.

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  • Session memory – who’s this guy named Max and what’s he doing with my memory?

    - by extended_events
    SQL Server MVP Jonathan Kehayias (blog) emailed me a question last week when he noticed that the total memory used by the buffers for an event session was larger than the value he specified for the MAX_MEMORY option in the CREATE EVENT SESSION DDL. The answer here seems like an excellent subject for me to kick-off my new “401 – Internals” tag that identifies posts where I pull back the curtains a bit and let you peek into what’s going on inside the extended events engine. In a previous post (Option Trading: Getting the most out of the event session options) I explained that we use a set of buffers to store the event data before  we write the event data to asynchronous targets. The MAX_MEMORY along with the MEMORY_PARTITION_MODE defines how big each buffer will be. Theoretically, that means that I can predict the size of each buffer using the following formula: max memory / # of buffers = buffer size If it was that simple I wouldn’t be writing this post. I’ll take “boundary” for 64K Alex For a number of reasons that are beyond the scope of this blog, we create event buffers in 64K chunks. The result of this is that the buffer size indicated by the formula above is rounded up to the next 64K boundary and that is the size used to create the buffers. If you think visually, this means that the graph of your max_memory option compared to the actual buffer size that results will look like a set of stairs rather than a smooth line. You can see this behavior by looking at the output of dm_xe_sessions, specifically the fields related to the buffer sizes, over a range of different memory inputs: Note: This test was run on a 2 core machine using per_cpu partitioning which results in 5 buffers. (Seem my previous post referenced above for the math behind buffer count.) input_memory_kb total_regular_buffers regular_buffer_size total_buffer_size 637 5 130867 654335 638 5 130867 654335 639 5 130867 654335 640 5 196403 982015 641 5 196403 982015 642 5 196403 982015 This is just a segment of the results that shows one of the “jumps” between the buffer boundary at 639 KB and 640 KB. You can verify the size boundary by doing the math on the regular_buffer_size field, which is returned in bytes: 196403 – 130867 = 65536 bytes 65536 / 1024 = 64 KB The relationship between the input for max_memory and when the regular_buffer_size is going to jump from one 64K boundary to the next is going to change based on the number of buffers being created. The number of buffers is dependent on the partition mode you choose. If you choose any partition mode other than NONE, the number of buffers will depend on your hardware configuration. (Again, see the earlier post referenced above.) With the default partition mode of none, you always get three buffers, regardless of machine configuration, so I generated a “range table” for max_memory settings between 1 KB and 4096 KB as an example. start_memory_range_kb end_memory_range_kb total_regular_buffers regular_buffer_size total_buffer_size 1 191 NULL NULL NULL 192 383 3 130867 392601 384 575 3 196403 589209 576 767 3 261939 785817 768 959 3 327475 982425 960 1151 3 393011 1179033 1152 1343 3 458547 1375641 1344 1535 3 524083 1572249 1536 1727 3 589619 1768857 1728 1919 3 655155 1965465 1920 2111 3 720691 2162073 2112 2303 3 786227 2358681 2304 2495 3 851763 2555289 2496 2687 3 917299 2751897 2688 2879 3 982835 2948505 2880 3071 3 1048371 3145113 3072 3263 3 1113907 3341721 3264 3455 3 1179443 3538329 3456 3647 3 1244979 3734937 3648 3839 3 1310515 3931545 3840 4031 3 1376051 4128153 4032 4096 3 1441587 4324761 As you can see, there are 21 “steps” within this range and max_memory values below 192 KB fall below the 64K per buffer limit so they generate an error when you attempt to specify them. Max approximates True as memory approaches 64K The upshot of this is that the max_memory option does not imply a contract for the maximum memory that will be used for the session buffers (Those of you who read Take it to the Max (and beyond) know that max_memory is really only referring to the event session buffer memory.) but is more of an estimate of total buffer size to the nearest higher multiple of 64K times the number of buffers you have. The maximum delta between your initial max_memory setting and the true total buffer size occurs right after you break through a 64K boundary, for example if you set max_memory = 576 KB (see the green line in the table), your actual buffer size will be closer to 767 KB in a non-partitioned event session. You get “stepped up” for every 191 KB block of initial max_memory which isn’t likely to cause a problem for most machines. Things get more interesting when you consider a partitioned event session on a computer that has a large number of logical CPUs or NUMA nodes. Since each buffer gets “stepped up” when you break a boundary, the delta can get much larger because it’s multiplied by the number of buffers. For example, a machine with 64 logical CPUs will have 160 buffers using per_cpu partitioning or if you have 8 NUMA nodes configured on that machine you would have 24 buffers when using per_node. If you’ve just broken through a 64K boundary and get “stepped up” to the next buffer size you’ll end up with total buffer size approximately 10240 KB and 1536 KB respectively (64K * # of buffers) larger than max_memory value you might think you’re getting. Using per_cpu partitioning on large machine has the most impact because of the large number of buffers created. If the amount of memory being used by your system within these ranges is important to you then this is something worth paying attention to and considering when you configure your event sessions. The DMV dm_xe_sessions is the tool to use to identify the exact buffer size for your sessions. In addition to the regular buffers (read: event session buffers) you’ll also see the details for large buffers if you have configured MAX_EVENT_SIZE. The “buffer steps” for any given hardware configuration should be static within each partition mode so if you want to have a handy reference available when you configure your event sessions you can use the following code to generate a range table similar to the one above that is applicable for your specific machine and chosen partition mode. DECLARE @buf_size_output table (input_memory_kb bigint, total_regular_buffers bigint, regular_buffer_size bigint, total_buffer_size bigint) DECLARE @buf_size int, @part_mode varchar(8) SET @buf_size = 1 -- Set to the begining of your max_memory range (KB) SET @part_mode = 'per_cpu' -- Set to the partition mode for the table you want to generate WHILE @buf_size <= 4096 -- Set to the end of your max_memory range (KB) BEGIN     BEGIN TRY         IF EXISTS (SELECT * from sys.server_event_sessions WHERE name = 'buffer_size_test')             DROP EVENT SESSION buffer_size_test ON SERVER         DECLARE @session nvarchar(max)         SET @session = 'create event session buffer_size_test on server                         add event sql_statement_completed                         add target ring_buffer                         with (max_memory = ' + CAST(@buf_size as nvarchar(4)) + ' KB, memory_partition_mode = ' + @part_mode + ')'         EXEC sp_executesql @session         SET @session = 'alter event session buffer_size_test on server                         state = start'         EXEC sp_executesql @session         INSERT @buf_size_output (input_memory_kb, total_regular_buffers, regular_buffer_size, total_buffer_size)             SELECT @buf_size, total_regular_buffers, regular_buffer_size, total_buffer_size FROM sys.dm_xe_sessions WHERE name = 'buffer_size_test'     END TRY     BEGIN CATCH         INSERT @buf_size_output (input_memory_kb)             SELECT @buf_size     END CATCH     SET @buf_size = @buf_size + 1 END DROP EVENT SESSION buffer_size_test ON SERVER SELECT MIN(input_memory_kb) start_memory_range_kb, MAX(input_memory_kb) end_memory_range_kb, total_regular_buffers, regular_buffer_size, total_buffer_size from @buf_size_output group by total_regular_buffers, regular_buffer_size, total_buffer_size Thanks to Jonathan for an interesting question and a chance to explore some of the details of Extended Event internals. - Mike

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  • Memory Profiling: How to detect which application/package is consuming too much memory

    - by malvim
    Hi, I have a situation here at work where we run a JEE server with several applications deployed on it. Lately, we've been having frequent OutOfMemoryException's. We suspect some of the apps might be behaving badly, maybe leaking, or something. The problem is, we can't really tell which one. We have run some memory profilers (like YourKit), and they're pretty good at telling what classes use the most memory. But they don't show relationships between classes, so that leaves us with a situation like this: We see that there are, say, lots of Strings and int arrays and HashMap entries, but we can't really tell which application or package they come from. Is there a way of knowing where these objects come from, so we can try to pinpoint the packages (or apps) that are allocating the most memory? Thank you in advance.

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  • Memory leak - debugger and memory analyzer disagreeing

    - by Joe
    There is a memory leak in my android game - I've managed to narrow it down to a certain object, which has a list of objects to render on a texture. This object clears the list every time it draws though - so I can't work out how its managed to get thousands of elements in the list. I checked in the debugger and it doesn't have all these thousands of elements - usually about 2-20 which is what I'd expect... The game definitely slows down progressively only if I have rendering to texturing on. Here is a picture of Memory Analyzer showing 6,111 items: Memory Analyzer Here is a picture of the debugger showing 2: Debugger Can anyone help me find out whats wrong?

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  • How In-Memory Database Objects Affect Database Design: Hybrid Code

    - by drsql
    In my first attempts at building my code, I strictly went with either native or on-disk code. I specifically wrote the on-disk code to only use features that worked in-memory. This lead to one majorly silly bit of code, used to create system assigned key values. How would I create a customer number that was unique. We can’t use the Max(value) + 1 approach because it will be very hideous with MVCC isolation levels, since 100 connections might see the same value, leading to lots of duplication. You...(read more)

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  • How do I secure Sql Server 2008 R2

    - by Mark Tait
    I have both a dedicated and a VPS (from Fasthosts) virtual server - the web sites/applications I run on these, access Sql Server stored on the same web server. Until now, I have logged onto Sql Server on both the deidicated and VPS server, from Sql Server Management Studio - until I noticed in my server application logs, multiple attempts to logon to Sql Server using the 'sa' username, but failed password. So someone/bot is trying hard (repeatedly every couple of hours, for approx 20 attempts during each instance) to log on... so obviously I have to lock down access to Sql Sever remotely. What I have done is gone into Configuration Manager, and in Sql Server Network Configuration - Protocols for Sql2008 and also in Sql Native Client 10.0 Configuration - Client Protocols - I have diabled Named Pipes, TCP/IP (and VIA by default). I have left Shared Memory enabled. I also disabled in Sql Server Services, the Sql Server Browser. Now the only way I can manage the databases on these servers, is by logging on to them via Remote Desktop. Can anyone confirm if this is the correct way of stopping anyone maliciously logging on to Sql Server? (I'm not a DBA or security expert - and there are hundreds of articles advising all different ways - but I was hoping for the experts here to confirm, or otherwise, if what I've done is correct) Thank you, Mark

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  • Problem with importing an mdf created with SQL Server Express 2008 into SQL Server 2005

    - by user252160
    The question is probably extremely easy to resolve, but I need to resolve it because I need to carry on with my project. I am using SQL Server Express 2008 at home, and I've been working on an ASP.NET MVC app that stores my DB in an mdf file in the project's folder. The problem is that the SQL Server in the Uni labs is SQL Server 2005, and when I try to open the mdf file with the VS Server Explorer,It says that the version of the mdf file is more than the server can accept. The only option that comes to my mind is exporting the DB as an sql file, just like I've done it thousand times with phpmyadmin. the thing is that the SQL Management Studio Express is not the most usable tool in the world, and for some strange reason all the articles I could find in Google were irrelevant. Please, help.

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  • Cumulative Updates for SQL Server 2005 SP3 and 2008 R2 are available

    - by AaronBertrand
    After releasing SQL Server 2005 SP4 on Friday (you can read more about it here ), the release services team did not hang up their hats for the Christmas holiday, but continued working on other releases. KB #2438344 : Cumulative update package 13 for SQL Server 2005 Service Pack 3 This brings your SQL Server 2005 SP3 build number to 9.00.4315 KB #2438347 : Cumulative Update package 5 for SQL Server 2008 R2 This brings your SQL Server 2008 R2 build number to 10.5.1753 NOTES: You will not be able to...(read more)

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  • Recap - SQL Saturday 151 in Orlando

    - by KKline
    It's always a feel-good experience for me to return to SQL Saturday in Orlando, the place where SQL Saturdays were started by Andy Warren ( Twitter | Blog ). On this trip, I delivered a full-day, pre-conference seminar on Troubleshooting and Performance Tuning SQL Server. I also delivered a session on SQL Server Internals and Architecture to a totally packed house. For those of you who emailed me directly, here's the link for the special SQL Sentry offer . I got to attend the extended events session...(read more)

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  • SQL Azure Federations and Semantic Search by the SQL product team in London tonight (Monday)

    - by simonsabin
    Don’t forget that tonight we have Michael Rys from the SQL Server Product Team presenting on the Federation support coming to SQL Azure and the Semantic search coming in SQL Server Denali. This is a must attend evening for anyone that is serious about scaling SQL or doing search in SQL Server. Michael also has a few other hats including Microsoft’s representative on the W3C XML Query Working Group. To register go to http://sqlsocial20110613.eventbrite.com/   Ps Beer and Pizza will be laid on...(read more)

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  • SQL 2014 does data the way developers want

    - by Rob Farley
    A post I’ve been meaning to write for a while, good that it fits with this month’s T-SQL Tuesday, hosted by Joey D’Antoni (@jdanton) Ever since I got into databases, I’ve been a fan. I studied Pure Maths at university (as well as Computer Science), and am very comfortable with Set Theory, which undergirds relational database concepts. But I’ve also spent a long time as a developer, and appreciate that that databases don’t exactly fit within the stuff I learned in my first year of uni, particularly the “Algorithms and Data Structures” subject, in which we studied concepts like linked lists. Writing in languages like C, we used pointers to quickly move around data, without a database in sight. Of course, if we had a power failure all this data was lost, as it was only persisted in RAM. Perhaps it’s why I’m a fan of database internals, of indexes, latches, execution plans, and so on – the developer in me wants to be reassured that we’re getting to the data as efficiently as possible. Back when SQL Server 2005 was approaching, one of the big stories was around CLR. Many were saying that T-SQL stored procedures would be a thing of the past because we now had CLR, and that obviously going to be much faster than using the abstracted T-SQL. Around the same time, we were seeing technologies like Linq-to-SQL produce poor T-SQL equivalents, and developers had had a gutful. They wanted to move away from T-SQL, having lost trust in it. I was never one of those developers, because I’d looked under the covers and knew that despite being abstracted, T-SQL was still a good way of getting to data. It worked for me, appealing to both my Set Theory side and my Developer side. CLR hasn’t exactly become the default option for stored procedures, although there are plenty of situations where it can be useful for getting faster performance. SQL Server 2014 is different though, through Hekaton – its In-Memory OLTP environment. When you create a table using Hekaton (that is, a memory-optimized one), the table you create is the kind of thing you’d’ve made as a developer. It creates code in C leveraging structs and pointers and arrays, which it compiles into fast code. When you insert data into it, it creates a new instance of a struct in memory, and adds it to an array. When the insert is committed, a small write is made to the transaction to make sure it’s durable, but none of the locking and latching behaviour that typifies transactional systems is needed. Indexes are done using hashes and using bw-trees (which avoid locking through the use of pointers) and by handling each updates as a delete-and-insert. This is data the way that developers do it when they’re coding for performance – the way I was taught at university before I learned about databases. Being done in C, it compiles to very quick code, and although these tables don’t support every feature that regular SQL tables do, this is still an excellent direction that has been taken. @rob_farley

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  • View all ntext column text in SQL Server Management Studio for SQL CE database

    - by Dave
    I often want to do a "quick check" of the value of a large text column in SQL Server Management Studio (SSMS). The maximum number of characters that SSMS will let you view, in grid results mode, is 65535. (It is even less in text results mode.) Sometimes I need to see something beyond that range. Using SQL Server 2005 databases, I often used the trick of converting it to XML, because SSMS lets you view much larger amounts of text that way: SELECT CONVERT(xml, MyCol) FROM MyTable WHERE ... But now I am using SQL CE, and there is no Xml data type. There is still a "Maximum Characters Retreived XML" value under Options; I suppose this is useful when connecting to other data sources. I know I can just get the full value by running a little console app or something, but is there a way within SSMS to see the entire ntext column value? [Edit] OK, this didn't get much attention the first time around (18 views?!). It's not a huge concern, but maybe I'm just obsessed with it. There has to be some good way around this, doesn't there? So a modest bounty is active. What I am willing to accept as answers, in order from best-to-worst: A solution that works just as easy as the XML trick in SQL CE. That is, a single function (convert, cast, etc.) that does the job. A not-too-invasive way to hack SSMS to get it to display more text in the results. An equivalent SQL query (perhaps something that creatively uses SUBSTRING and generates multiple ad-hoc columns??) to see the results. The solution should work with nvarchar and ntext columns of any length in SQL CE from SSMS. Any ideas?

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  • Memory dump much smaller than available memory

    - by Daniel
    I have a Tomcat Application Server that is configured to create a memory dump on OOM, and it is started with -Xmx1024M, so a Gigabyte should be available to him. Now I found one such dump and it contains only 260MB of unretained memory. How is it possible that the dump is so much smaller than the size he should have available?

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  • Is SQL Azure a newbies springboard?

    - by jamiet
    Earlier today I was considering the various SQL Server platforms that are available today and I wondered aloud, wonder how long until the majority of #sqlserver newcomers use @sqlazure instead of installing locally Let me explain. My first experience of development was way back in the early 90s when I would crank open VBA in Access or Excel and start hammering out some code, usually by recording macros and looking at the code that they produced (sound familiar?). The reason was simple, Office was becoming ubiquitous so the barrier to entry was incredibly low and, save for a short hiatus at university, I’ve been developing on the Microsoft platform ever since. These days spend most of my time using SQL Server. I take a look at SQL Azure today I see a lot of similarities with those early experiences, the barrier to entry is low and getting lower. I don’t have to download some software or actually install anything other than a web browser in order to get myself a fully functioning SQL Server  database against which I can ostensibly start hammering out some code and I believe that to be incredibly empowering. Having said that there are still a few pretty high barriers, namely: I need to get out my credit card Its pretty useless without some development tools such as SQL Server Management Studio, which I do have to install. The second of those barriers will disappear pretty soon when Project Houston delivers a web-based admin and presentation tool for SQL Azure so that just leaves the matter of my having to use a credit card. If Microsoft have any sense at all then they will realise the huge potential of opening up a free, throttled version of SQL Azure for newbies to party on; they get to developers early (just like they did with me all those years ago) and it gives potential customers an opportunity to try-before-they-buy. Perhaps in 20 years time people will be talking about SQL Azure as being their first foray into the world of coding! @Jamiet Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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  • what kind of memory can be categorized as Modified Memory in Resource Monitor

    - by Kavin
    In Windows 7 and Windows 2008 R2, there is a new Resource Monitor that is very useful and powerful to monitor the system. In the Memory section, I see a section called Modified (orange) The official description is: Memory whose contents must be to disk before it can be used for another purpose. But I am still confused. What kinds of memory is Modified? In which case can we say that this number of memory is Modified? Can anyone give me a specific example? Is the following guess correct? When a program want to write something into disk, it actually write the content to an IO buffer, which is in the memory. After OS flush this area of memory into disk, the memory is modified or standby?

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  • very large string in memory

    - by bushman
    Hi, I am writing a program for formatting 100s of MB String data (nearing a gig) into xml == And I am required to return it as a response to an HTTP (GET) request . I am using a StringWriter/XmlWriter to build an XML of the records in a loop and returning the stringWriter.ToString() during testing I saw a few --out of memory exceptions-- and quite clueless on how to find a solution? do you guys have any suggestions for a memory optimized delivery of the response? is there a memory efficient way of encoding the data? or maybe chunking the data -- I just can not think of how to return it without building the whole thing into one HUGE string object thanks

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