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  • Why do packages fail to install from command line

    - by calebB
    Every once in a while I can't install packages in Ubuntu 11.04. I'll try to run the software center and it and it will pop up then disappear. If I call it from the command line it says it seg-faults. And then trying to install anything from the command line I get this: sudo apt-get install pdftk Reading package lists... Done And thats all I get for anything I try. Usually restarting fixes the problem but its very annoying.

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  • Stucked in the grub command prompt

    - by user903645
    I have a windows xp os, and I ve decided to give ubuntu a shot. I installed and It when rebooting it did boot by default windows. I red several forums and after entering those commands: sudo mkdir /mnt/ubuntu sudo mount /dev/sda2 /mnt/ubuntu sudo grub-install /dev/sda --root -directory=/mnt/ubuntu after rebooting the system showed me the command grub. And I cannot get anywhere. I don t have a windows cd to fix anything. so how can I launch windows from this command grub? Thanks... I am in a real mess.

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  • (SYSLINUX QUESTION) How to launch command prompt once syslinux boots up

    - by user1294023
    I have created a bootable USB drive using SYSLINUX I am booting my x86 system correctly. Once system boots I want to stop at console (command prompt) where I can type linux commands (cd etc) and run my executable file manually. Does that mean I have to have busy box installed (for basic commands). What makes system stop at command prompt? I do have /dev/console. My serial console is tty1. Any help is appreciated. #syslinux.cfg serial 0 9600 default MyProgram prompt 1 label Linux display message.msg timeout 100 kernel bzImage append console=tty1,9600 vga=773 initrd initrd.img

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  • Usage of putty in command line from Hudson

    - by kij
    Hi, I'm trying to use putty in command line from an hudson job. The command is the following one: putty -ssh -2 -P 22 USERNAME@SERVER_ADDR -pw PASS -m command.txt Where 'command.txt' is a shell script to execute in the server through SSH. If i launch this command from the Window command prompt, it works, the shell script is executed on the server machine. If i launch a build of the hudson job configured with this batch command, it doesn't work. The build is running... and running... and running.. without doing anything, and i have to stop it manually. So my question is: Is it possible to launch an external programm (i.e. putty) from an hudson job ? ps: i tried SSH plugin but... not a really good plugin (pre/post build, fail status of the commands launched not caught by hudson, etc.) Thanks in advance for your help. Best regards. kij EDIT: These are the build logs: [workspace] $ cmd /c call C:\WINDOWS\TEMP\hudson7429256014041663539.bat C:\Hudson\jobs\Artifact deployer\workspace>putty -ssh -2 -P 22 USER@SERV_ADD -pw PASS -m com.txt Le build a été annulé Finished: ABORTED And the Hudson.err.log file at the same time (after a stop): 3 juin 2010 18:27:28 hudson.model.Run run INFO: Artifact deployer #6 aborted java.lang.InterruptedException at java.lang.ProcessImpl.waitFor(Native Method) at hudson.Proc$LocalProc.join(Proc.java:179) at hudson.Launcher$ProcStarter.join(Launcher.java:278) at hudson.tasks.CommandInterpreter.perform(CommandInterpreter.java:83) at hudson.tasks.CommandInterpreter.perform(CommandInterpreter.java:58) at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19) at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:601) at hudson.model.Build$RunnerImpl.build(Build.java:174) at hudson.model.Build$RunnerImpl.doRun(Build.java:138) at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:416) at hudson.model.Run.run(Run.java:1241) at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46) at hudson.model.ResourceController.execute(ResourceController.java:88) at hudson.model.Executor.run(Executor.java:124) My shell script only write "hello" in a "hello.txt" file on the server, and nothing is done.

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  • could not resolve property (complex properties)

    - by felipeoriani
    I have a asp.net mvc application with NHibernate and I do not know how to resolve a problem to query some data. I have this query: // create query var query = session.QueryOVer<Laudo>().Fetch(x => x.Equipament).Eager; // add some filters if (idEquipament.HasValue) query = query.And(x => x.Equipament.Id == idEquipament.Value); //I got the error here... if (idCompany.HasValue) query = query.And(x => x.Equipament.Company.Id == idCompany.Value); When I try to execute this query, I've got an exception with this message: "could not resolve property: Equipament.Company.Id of: DomainModel.Laudo" what can I do to fix this problem? Thanks

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  • SQL SEVER – Finding Memory Pressure – External and Internal

    - by pinaldave
    Following query will provide details of external and internal memory pressure. It will return the data how much portion in the existing memory is assigned to what kind of memory type. SELECT TYPE, SUM(single_pages_kb) InternalPressure, SUM(multi_pages_kb) ExtermalPressure FROM sys.dm_os_memory_clerks GROUP BY TYPE ORDER BY SUM(single_pages_kb) DESC, SUM(multi_pages_kb) DESC GO What is your method to find memory pressure? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Challenge – Puzzle – Usage of FAST Hint

    - by pinaldave
    I was recently working with various SQL Server Hints. After working for a day on various hints, I realize that for one hint, I am not able to come up with good example. The hint is FAST. Let us look at the definition of the FAST hint from the Book On-Line. FAST number_rows Specifies that the query is optimized for fast retrieval of the first number_rows. This is a nonnegative integer. After the first number_rows are returned, the query continues execution and produces its full result set. Now the question is in what condition this hint can be useful. I have tried so many different combination, I have found this hint does not make much performance difference, infect I did not notice any change in time taken to load the resultset. I noticed that this hint does not change number of the page read to return result. Now when there is difference in performance is expected because if you read the what FAST hint does is that it only returns first few results FAST – which does not mean there will be difference in performance. I also understand that this hint gives the guidance/suggestions/hint to query optimizer that there are only 100 rows are in expected resultset. This tricking the optimizer to think there are only 100 rows and which (may) lead to render different execution plan than the one which it would have taken in normal case (without hint). Again, not necessarily, this will happen always. Now if you read above discussion, you will find that basic understanding of the hint is very clear to me but I still feel that I am missing something. Here are my questions: 1) In what condition this hint can be useful? What is the case, when someone want to see first few rows early because my experience suggests that when first few rows are rendered remaining rows are rendered as well. 2) Is there any way application can retrieve the fast fetched rows from SQL Server? 3) Do you use this hint in your application? Why? When? and How? Here are few examples I have attempted during the my experiment and found there is no difference in execution plan except its estimated number of rows are different leading optimizer think that the cost is less but in reality that is not the case. USE AdventureWorks GO SET STATISTICS IO ON SET STATISTICS TIME ON GO --------------------------------------------- -- Table Scan with Fast Hint SELECT * FROM Sales.SalesOrderDetail GO SELECT * FROM Sales.SalesOrderDetail OPTION (FAST 100) GO --------------------------------------------- -- Table Scan with Where on Index Key SELECT * FROM Sales.SalesOrderDetail WHERE OrderQty = 14 GO SELECT * FROM Sales.SalesOrderDetail WHERE OrderQty = 14 OPTION (FAST 100) GO --------------------------------------------- -- Table Scan with Where on Index Key SELECT * FROM Sales.SalesOrderDetail WHERE SalesOrderDetailID < 1000 GO SELECT * FROM Sales.SalesOrderDetail WHERE SalesOrderDetailID < 1000 OPTION (FAST 100) GO Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video

    - by pinaldave
    You might have heard many times that one should not use SELECT * as there are many disadvantages to the usage of the SELECT *. I also believe that there are always rare occasion when we need every single column of the query. In most of the cases, we only need a few columns of the query and we should retrieve only those columns. SELECT * has many disadvantages. Let me list a few and remaining you can add as a comment.  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug. There are two quick tricks I have discussed in the video which explains how users can avoid using SELECT * but instead list the column names. 1) Drag the columns folder from SQL Server Management Studio to Query Editor 2) Right Click on Table Name >> Script TAble AS >> SELECT To… >> Select option It is extremely easy to list the column names in the table. In today’s sixty seconds video, you will notice that I was able to demonstrate both the methods very quickly. From now onwards there should be no excuse for not listing ColumnName. Let me ask a question back – is there ever a reason to SELECT *? If yes, would you please share that as a comment. More on SELECT *: SQL SERVER – Solution – Puzzle – SELECT * vs SELECT COUNT(*) SQL SERVER – Puzzle – SELECT * vs SELECT COUNT(*) SQL SERVER – SELECT vs. SET Performance Comparison I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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  • SQL SERVER – Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies

    - by pinaldave
    A very common question which I often receive are: How do I find all the tables used in a particular stored procedure? How do I know which stored procedures are using a particular table? Both are valid question but before we see the answer of this question – let us understand two small concepts – Referenced and Referencing. Here is the sample stored procedure. CREATE PROCEDURE mySP AS SELECT * FROM Sales.Customer GO Reference: The table Sales.Customer is the reference object as it is being referenced in the stored procedure mySP. Referencing: The stored procedure mySP is the referencing object as it is referencing Sales.Customer table. Now we know what is referencing and referenced object. Let us run following queries. I am using AdventureWorks2012 as a sample database. If you do not have SQL Server 2012 here is the way to get SQL Server 2012 AdventureWorks database. Find Referecing Objects of a particular object Here we are finding all the objects which are using table Customer in their object definitions (regardless of the schema). USE AdventureWorks GO SELECT referencing_schema_name = SCHEMA_NAME(o.SCHEMA_ID), referencing_object_name = o.name, referencing_object_type_desc = o.type_desc, referenced_schema_name, referenced_object_name = referenced_entity_name, referenced_object_type_desc = o1.type_desc, referenced_server_name, referenced_database_name --,sed.* -- Uncomment for all the columns FROM sys.sql_expression_dependencies sed INNER JOIN sys.objects o ON sed.referencing_id = o.[object_id] LEFT OUTER JOIN sys.objects o1 ON sed.referenced_id = o1.[object_id] WHERE referenced_entity_name = 'Customer' The above query will return all the objects which are referencing the table Customer. Find Referenced Objects of a particular object Here we are finding all the objects which are used in the view table vIndividualCustomer. USE AdventureWorks GO SELECT referencing_schema_name = SCHEMA_NAME(o.SCHEMA_ID), referencing_object_name = o.name, referencing_object_type_desc = o.type_desc, referenced_schema_name, referenced_object_name = referenced_entity_name, referenced_object_type_desc = o1.type_desc, referenced_server_name, referenced_database_name --,sed.* -- Uncomment for all the columns FROM sys.sql_expression_dependencies sed INNER JOIN sys.objects o ON sed.referencing_id = o.[object_id] LEFT OUTER JOIN sys.objects o1 ON sed.referenced_id = o1.[object_id] WHERE o.name = 'vIndividualCustomer' The above query will return all the objects which are referencing the table Customer. I am just glad to write above query. There are more to write to this subject. In future blog post I will write more in depth about other DMV which also aids in finding referenced data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL Tips and Tricks, SQL Utility, T SQL, Technology

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  • SQL SERVER – A Puzzle – Fun with NULL – Fix Error 8117

    - by pinaldave
    During my 8 years of career, I have been involved in many interviews. Quite often, I act as the  interview. If I am the interviewer, I ask many questions – from easy questions to difficult ones. When I am the interviewee, I frequently get an opportunity to ask the interviewer some questions back. Regardless of the my capacity in attending the interview, I always make it a point to ask the interviewer at least one question. What is NULL? It’s always fun to ask this question during interviews, because in every interview, I get a different answer. NULL is often confused with false, absence of value or infinite value. Honestly, NULL is a very interesting subject as it bases its behavior in server settings. There are a few properties of NULL that are universal, but the knowledge about these properties is not known in a universal sense. Let us run this simple puzzle. Run the following T-SQL script: SELECT SUM(data) FROM (SELECT NULL AS data) t It will return the following error: Msg 8117, Level 16, State 1, Line 1 Operand data type NULL is invalid for sum operator. Now the error makes it very clear that NULL is invalid for sum Operator. Frequently enough, I have showed this simple query to many folks whom I came across. I asked them if they could modify the subquery and return the result as NULL. Here is what I expected: Even though this is a very simple looking query, so far I’ve got the correct answer from only 10% of the people to whom I have asked this question. It was common for me to receive this kind of answer – convert the NULL to some data type. However, doing so usually returns the value as 0 or the integer they passed. SELECT SUM(data) FROM (SELECT ISNULL(NULL,0) AS data) t I usually see many people modifying the outer query to get desired NULL result, but that is not allowed in this simple puzzle. This small puzzle made me wonder how many people have a clear understanding about NULL. Well, here is the answer to my simple puzzle. Just CAST NULL AS INT and it will return the final result as NULL: SELECT SUM(data) FROM (SELECT CAST(NULL AS INT) AS data) t Now that you know the answer, don’t you think it was very simple indeed? This blog post is especially dedicated to my friend Madhivanan who has written an excellent blog post about NULL. I am confident that after reading the blog post from Madhivanan, you will have no confusion regarding NULL in the future. Read: NULL, NULL, NULL and nothing but NULL. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL University: Parallelism Week - Part 3, Settings and Options

    - by Adam Machanic
    Congratulations! You've made it back for the the third and final installment of Parallelism Week here at SQL University . So far we've covered the fundamentals of multitasking vs. parallel processing and delved into how parallel query plans actually work . Today we'll take a look at the settings and options that influence intra-query parallelism and discuss how best to set things up in various situations. Instance-Level Configuration Your database server probably has more than one logical processor....(read more)

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  • SQL SERVER – Weekly Series – Memory Lane – #048

    - by Pinal Dave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Order of Result Set of SELECT Statement on Clustered Indexed Table When ORDER BY is Not Used Above theory is true in most of the cases. However SQL Server does not use that logic when returning the resultset. SQL Server always returns the resultset which it can return fastest.In most of the cases the resultset which can be returned fastest is the resultset which is returned using clustered index. Effect of TRANSACTION on Local Variable – After ROLLBACK and After COMMIT One of the Jr. Developer asked me this question (What will be the Effect of TRANSACTION on Local Variable – After ROLLBACK and After COMMIT?) while I was rushing to an important meeting. I was getting late so I asked him to talk with his Application Tech Lead. When I came back from meeting both of them were looking for me. They said they are confused. I quickly wrote down following example for them. 2008 SQL SERVER – Guidelines and Coding Standards Complete List Download Coding standards and guidelines are very important for any developer on the path of a successful career. A coding standard is a set of guidelines, rules and regulations on how to write code. Coding standards should be flexible enough or should take care of the situation where they should not prevent best practices for coding. They are basically the guidelines that one should follow for better understanding. Download Guidelines and Coding Standards complete List Download Get Answer in Float When Dividing of Two Integer Many times we have requirements of some calculations amongst different fields in Tables. One of the software developers here was trying to calculate some fields having integer values and divide it which gave incorrect results in integer where accurate results including decimals was expected. Puzzle – Computed Columns Datatype Explanation SQL Server automatically does a cast to the data type having the highest precedence. So the result of INT and INT will be INT, but INT and FLOAT will be FLOAT because FLOAT has a higher precedence. If you want a different data type, you need to do an EXPLICIT cast. Renaming SP is Not Good Idea – Renaming Stored Procedure Does Not Update sys.procedures I have written many articles about renaming a tables, columns and procedures SQL SERVER – How to Rename a Column Name or Table Name, here I found something interesting about renaming the stored procedures and felt like sharing it with you all. The interesting fact is that when we rename a stored procedure using SP_Rename command, the Stored Procedure is successfully renamed. But when we try to test the procedure using sp_helptext, the procedure will be having the old name instead of new names. 2009 Insert Values of Stored Procedure in Table – Use Table Valued Function It is clear from the result set that , where I have converted stored procedure logic into the table valued function, is much better in terms of logic as it saves a large number of operations. However, this option should be used carefully. The performance of the stored procedure is “usually” better than that of functions. Interesting Observation – Index on Index View Used in Similar Query Recently, I was working on an optimization project for one of the largest organizations. While working on one of the queries, we came across a very interesting observation. We found that there was a query on the base table and when the query was run, it used the index, which did not exist in the base table. On careful examination, we found that the query was using the index that was on another view. This was very interesting as I have personally never experienced a scenario like this. In simple words, “Query on the base table can use the index created on the indexed view of the same base table.” Interesting Observation – Execution Plan and Results of Aggregate Concatenation Queries Working with SQL Server has never seemed to be monotonous – no matter how long one has worked with it. Quite often, I come across some excellent comments that I feel like acknowledging them as blog posts. Recently, I wrote an article on SQL SERVER – Execution Plan and Results of Aggregate Concatenation Queries Depend Upon Expression Location, which is well received in the community. 2010 I encourage all of you to go through complete series and write your own on the subject. If you write an article and send it to me, I will publish it on this blog with due credit to you. If you write on your own blog, I will update this blog post pointing to your blog post. SQL SERVER – ORDER BY Does Not Work – Limitation of the View 1 SQL SERVER – Adding Column is Expensive by Joining Table Outside View – Limitation of the View 2 SQL SERVER – Index Created on View not Used Often – Limitation of the View 3 SQL SERVER – SELECT * and Adding Column Issue in View – Limitation of the View 4 SQL SERVER – COUNT(*) Not Allowed but COUNT_BIG(*) Allowed – Limitation of the View 5 SQL SERVER – UNION Not Allowed but OR Allowed in Index View – Limitation of the View 6 SQL SERVER – Cross Database Queries Not Allowed in Indexed View – Limitation of the View 7 SQL SERVER – Outer Join Not Allowed in Indexed Views – Limitation of the View 8 SQL SERVER – SELF JOIN Not Allowed in Indexed View – Limitation of the View 9 SQL SERVER – Keywords View Definition Must Not Contain for Indexed View – Limitation of the View 10 SQL SERVER – View Over the View Not Possible with Index View – Limitations of the View 11 2011 Startup Parameters Easy to Configure If you are a regular reader of this blog, you must be aware that I have written about SQL Server Denali recently. Here is the quickest way to reach into the screen where we can change the startup parameters. Go to SQL Server Configuration Manager >> SQL Server Services >> Right Click on the Server >> Properties >> Startup Parameters 2012 Validating Unique Columnname Across Whole Database I sometimes come across very strange requirements and often I do not receive a proper explanation of the same. Here is the one of those examples. For example “Our business requirement is when we add new column we want it unique across current database.” Read the solution to this strange request in this blog post. Excel Losing Decimal Values When Value Pasted from SSMS ResultSet It is very common when users are coping the resultset to Excel, the floating point or decimals are missed. The solution is very much simple and it requires a small adjustment in the Excel. By default Excel is very smart and when it detects the value which is getting pasted is numeric it changes the column format to accommodate that. Basic Calculation and PEMDAS Order of Operation Read this interesting blog post for fantastic conversation about the subject. Copy Column Headers from Resultset – SQL in Sixty Seconds #027 – Video http://www.youtube.com/watch?v=x_-3tLqTRv0 Delete From Multiple Table – Update Multiple Table in Single Statement There are two questions which I get every single day multiple times. In my gmail, I have created standard canned reply for them. Let us see the questions here. I want to delete from multiple table in a single statement how will I do it? I want to update multiple table in a single statement how will I do it? Read the answer in the blog post. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – BI Quiz Hint – Performance Tuning Cubes – Hints

    - by pinaldave
    I earlier wrote about SQL BI Quiz over here and here. The details of the quiz is here: Working with huge data is very common when it is about Data Warehousing. It is necessary to create Cubes on the data to make it meaningful and consumable. There are cases when retrieving the data from cube takes lots of the time. Let us assume that your cube is returning you data very quickly. Suddenly on one day it is returning the data very slowly. What are the three things will you to diagnose this. After diagnose what you will do to resolve performance issue. Participate in my question over here I required BI Expert Jason Thomas to help with few hints to blog readers. He is one of the leading SSAS expert and writes a complicated subject in simple words. If queries were executing properly before but now take a long time to return the data, it means that there has been a change in the environment in which it is running. Some possible changes are listed below:-  1) Data factors:- Compare the data size then and now. Increase in data can result in different execution times. Poorly written queries as well as poor design will not start showing issues till the data grows. How to find it out? (Ans : SQL Server profiler and Perfmon Counters can be used for identifying the issues and performance  tuning the MDX queries)  2) Internal Factors:- Is some slow MDX query / multiple mdx queries running at the same time, which was not running when you had tested it before? Is there any locking happening due to proactive caching or processing operations? Are the measure group caches being cleared by processing operations? (Ans : Again, profiler and perfmon counters will help in finding it out. Load testing can be done using AS Performance Workbench (http://asperfwb.codeplex.com/) by running multiple queries at once)  3) External factors:- Is some other application competing for the same resources?  HINT : Read “Identifying and Resolving MDX Query Performance Bottlenecks in SQL Server 2005 Analysis Services” (http://sqlcat.com/whitepapers/archive/2007/12/16/identifying-and-resolving-mdx-query-performance-bottlenecks-in-sql-server-2005-analysis-services.aspx) Well, these are great tips. Now win big prizes by participate in my question over here. 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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  • SQLbits London 2012 - Demos

    - by Adam Machanic
    Thanks to everyone who attended my sessions last Friday and Saturday at SQLbits! It was great to meet many new people, not to mention spending some time exploring one of my favorite cities, London. Attached are the demos for each of the two talks I delivered: Query Tuning Mastery: The Art of and Science of Manhandling Parallelism As a database developer, your job boils down to one word: performance. And in today's multi-core-driven world, query performance is very much determined by how well you're...(read more)

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  • Is there an equivalent of jsqlparser but for SPARQL instead of SQL?

    - by Programmer
    I'm trying to use Java to construct a SPARQL query, and then send it off to a remote database. However, I'm new to both Java and SPARQL, so I was wondering if anyone could explain how to do this, rather than just posting a link. I heard there is a tool called jsqlparser for the same task, except that it's for a SQL to SPARQL conversion using Java. Conversion nor parser won't be necessary, just a method for constructing a query and querying the database provided by the user.

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  • Why isn't my query using any indices when I use a subquery?

    - by sfussenegger
    I have the following tables (removed columns that aren't used for my examples): CREATE TABLE `person` ( `id` int(11) NOT NULL, `name` varchar(1024) NOT NULL, `sortname` varchar(1024) NOT NULL, PRIMARY KEY (`id`), KEY `sortname` (`sortname`(255)), KEY `name` (`name`(255)) ); CREATE TABLE `personalias` ( `id` int(11) NOT NULL, `person` int(11) NOT NULL, `name` varchar(1024) NOT NULL, PRIMARY KEY (`id`), KEY `person` (`person`), KEY `name` (`name`(255)) ) Currently, I'm using this query which works just fine: select p.* from person p where name = 'John Mayer' or sortname = 'John Mayer'; mysql> explain select p.* from person p where name = 'John Mayer' or sortname = 'John Mayer'; +----+-------------+-------+-------------+---------------+---------------+---------+------+------+----------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------------+---------------+---------------+---------+------+------+----------------------------------------------+ | 1 | SIMPLE | p | index_merge | name,sortname | name,sortname | 767,767 | NULL | 3 | Using sort_union(name,sortname); Using where | +----+-------------+-------+-------------+---------------+---------------+---------+------+------+----------------------------------------------+ 1 row in set (0.00 sec) Now I'd like to extend this query to also consider aliases. First, I've tried using a join: select p.* from person p join personalias a where p.name = 'John Mayer' or p.sortname = 'John Mayer' or a.name = 'John Mayer'; mysql> explain select p.* from person p join personalias a on p.id = a.person where p.name = 'John Mayer' or p.sortname = 'John Mayer' or a.name = 'John Mayer'; +----+-------------+-------+--------+-----------------------+---------+---------+-------------------+-------+-----------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+-----------------------+---------+---------+-------------------+-------+-----------------+ | 1 | SIMPLE | a | ALL | ref,name | NULL | NULL | NULL | 87401 | Using temporary | | 1 | SIMPLE | p | eq_ref | PRIMARY,name,sortname | PRIMARY | 4 | musicbrainz.a.ref | 1 | Using where | +----+-------------+-------+--------+-----------------------+---------+---------+-------------------+-------+-----------------+ 2 rows in set (0.00 sec) This looks bad: no index, 87401 rows, using temporary. Using temporary only appears when I use distinct, but as an alias might be the same as the name, I can't really get rid of it. Next, I've tried to replace the join with a subquery: select p.* from person p where p.name = 'John Mayer' or p.sortname = 'John Mayer' or p.id in (select person from personalias a where a.name = 'John Mayer'); mysql> explain select p.* from person p where p.name = 'John Mayer' or p.sortname = 'John Mayer' or p.id in (select id from personalias a where a.name = 'John Mayer'); +----+--------------------+-------+----------------+------------------+--------+---------+------+--------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+--------------------+-------+----------------+------------------+--------+---------+------+--------+-------------+ | 1 | PRIMARY | p | ALL | name,sortname | NULL | NULL | NULL | 540309 | Using where | | 2 | DEPENDENT SUBQUERY | a | index_subquery | person,name | person | 4 | func | 1 | Using where | +----+--------------------+-------+----------------+------------------+--------+---------+------+--------+-------------+ 2 rows in set (0.00 sec) Again, this looks pretty bad: no index, 540309 rows. Interestingly, both queries (select p.* from person ... or p.id in (4711,12345) and select id from personalias a where a.name = 'John Mayer') work extremely well. Why doesn't MySQL use any indices for both of my queries? What else could I do? Currently, it looks best to fetch person.ids for aliases and add them statically as an in(...) to the second query. There certainly has to be another way to do this with a single query. I'm currently out of ideas though. Could I somehow force MySQL into using another (better) query plan?

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  • How do I run a sudo command in Emacs?

    - by Inaimathi
    I tried using shell-command, but it just does something like this: Sudo password: incorrect, try again. Sudo password: incorrect, try again. Sudo password: incorrect, try again. Failed three attempts. without actually asking for a password. I don't want to have to start up Emacs using sudo emacs, but I guess that's an option if nothing else will work.

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  • Command line tool in python in a fixed root directory ...

    - by koleto
    I would like to install my python application as a command line tool that should work entirelly inside the install directory (for example C:\Python26\Lib\site-packages\application) The problem is I would like to reffer in runtime to the submodules and resources from within the application directory three. If I install the app with [console_scripts] option the default path is the current directory. Is there a elegant way to keep the current execution path of the application to the site-packages directory? Thanks

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  • a command line or a script who is able to display each version of each element archived in a vob sin

    - by TaintedLove
    Hello, For example, I am in a vob called: avob I add to source control a folder: avob/afolder I add to source control two files afile1 and afile2 avob/afolder/afile1 avob/afolder/afile2 I uncatalogued the file afile2 I add to source control afile3 avob/afolder/afile3 I would like (a command line or a script who is able to) display each version of each element archived since the beginning, here: avob@version1 avob@version2 avob@version2/afile1@version1 avob@version2/afile2@version1 avob@version3 avob@version3/afile1@version1 avob@version4 avob@version4/afile1@version1 avob@version4/afile3@version1

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