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  • Optimizing MySQL statement with lot of count(row) an sum(row+row2)...

    - by Zombies
    I need to use InnoDB storage engine on a table with about 1mil or so records in it at any given time. It has records being inserted to it at a very fast rate, which are then dropped within a few days, maybe a week. The ping table has about a million rows, whereas the website table only about 10,000. My statement is this: select url from website ws, ping pi where ws.idproxy = pi.idproxy and pi.entrytime > curdate() - 3 and contentping+tcpping is not null group by url having sum(contentping+tcpping)/(count(*)-count(errortype)) < 500 and count(*) > 3 and count(errortype)/count(*) < .15 order by sum(contentping+tcpping)/(count(*)-count(errortype)) asc; I added an index on entrytime, yet no dice. Can anyone throw me a bone as to what I should consider to look into for basic optimization of this query. The result set is only like 200 rows, so I'm not getting killed there.

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  • How do I replace NOT EXISTS with JOIN?

    - by YelizavetaYR
    I've got the following query: select distinct a.id, a.name from Employee a join Dependencies b on a.id = b.eid where not exists ( select * from Dependencies d where b.id = d.id and d.name = 'Apple' ) and exists ( select * from Dependencies c where b.id = c.id and c.name = 'Orange' ); I have two tables, relatively simple. The first Employee has an id column and a name column The second table Dependencies has 3 column, an id, an eid (employee id to link) and names (apple, orange etc). the data looks like this Employee table looks like this id | name ----------- 1 | Pat 2 | Tom 3 | Rob 4 | Sam Dependencies id | eid | Name -------------------- 1 | 1 | Orange 2 | 1 | Apple 3 | 2 | Strawberry 4 | 2 | Apple 5 | 3 | Orange 6 | 3 | Banana As you can see Pat has both Orange and Apple and he needs to be excluded and it has to be via joins and i can't seem to get it to work. Ultimately the data should only return Rob

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  • What is the difference between these two LINQ statements?

    - by jamone
    I had the 1nd statement in my code and found it not giving an accurate count, it was returning 1 when the correct answer is 18. To try and debug the problem I broke it out creating the 2nd statement here and the count returns 18. I just don't see what the difference is between these two. It seems like the 1st is just more compact. I'm currently running these two statements back to back and I'm sure that the database isn't changing between the two. int count = (from s in surveysThisQuarter where s.FacilityID == facility.LocationID select s.Deficiencies).Count(); vs var tempSurveys = from s in surveysThisQuarter where s.FacilityID == facility.LocationID select s; int count = 0; foreach (Survey s in tempSurveys) count += s.Deficiencies.Count();

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  • HTML5 Web Database Security

    - by Daniel Dimovski
    Should the HTML5 database be used to store any form of private information? Say we have the following scenario; You're browsing a web-mail client, that uses the web database to store mail drafts after you've written some information you close the web browser. What's to stop me from getting access to this information? If the webpage tries to clean out old information when opened a user-script could easily prevent the website from fully loading and then search through the database. Furthermore the names of databases and tables are easily available through the web-mail client's source. W3C Draft

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  • Linq issue retrieving single value from mssql

    - by Anicho
    Hey Guys, having an issue with linq, I am basically doing the following but it is saying it is "UserProfile does not contain definition for Username" in the current context where I wrote "u.Username" but it does exist I have added UserProfile table to MyDbml.dbml and if I connect to another table it works fine. TiamoDataContext context = new TiamoDataContext(); var user = (from u in context.UserProfiles where u.Username == UsernameLabel select u).FirstOrDefault(); I am flustered by what small detail I have missed out to get this to work, anyone have any clues it would be much appreciation.

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  • why is there extra using where in execution plan of query

    - by user366534
    I see plan of query: EXPLAIN SELECT * FROM `subscribers` WHERE state =4 AND date_added < '2010-12-23 11:47:45' It shows: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE subscribers range state_date_added state_date_added 9 NULL 8 Using where Here is indexes of table: Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment subscribers 0 PRIMARY 1 subscriber_id A 382039 NULL NULL BTREE subscribers 0 email_list_id 1 email_address A 191019 NULL NULL BTREE subscribers 0 email_list_id 2 list_id A 382039 NULL NULL BTREE subscribers 1 FK_list_id 1 list_id A 10 NULL NULL BTREE subscribers 1 state_date_added 1 state A 12 NULL NULL BTREE subscribers 1 state_date_added 2 date_added A 8128 NULL NULL BTREE The last two lines describes index what is supposed for the query. Why is there in extra column using where? Even If I fetch only state and date_added column, it has in extra column: Using where; Using index. I understand why it has using index, but I don't understand Using where here.

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  • Retrieving Top 10 rows ans sum all others in row 11

    - by Mario
    Hello all, I have the following query that retrieve the number of users per country; SELECT C.CountryID AS CountryID, C.CountryName AS Country, Count(FirstName) AS Origin FROM Users AS U INNER JOIN Country AS C ON C.CountryID = U.CountryOfOrgin GROUP BY CASE C.CountryName, C.CountryID What I need is a way to get the top 10 and then sum all other users in a single row. I know how to get the top 10 but I`m stuck on getting the remaining in a single row. Is there a simple way to do it? For example if the above query returns 17 records the top ten are displayed and a sum of the users from the 7 remaining country should appear on row 11. On that row 11 the countryid would be 0 and countryname Others Thanks for your help!

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  • Custom SQL function for NHibernate dialect

    - by Kristoffer Ahl
    I want to be able to call a custom function called "recent_date" as part of my HQL. Like this: [Date] >= recent_date() I created a new dialect, inheriting from MsSql2000Dialect and specified the dialect for my configuration. public class NordicMsSql2000Dialect : MsSql2000Dialect { public NordicMsSql2000Dialect() { RegisterFunction( "recent_date", new SQLFunctionTemplate( NHibernateUtil.Date, "dateadd(day, -15, getdate())" ) ); } } var configuration = Fluently.Configure() .Database( MsSqlConfiguration.MsSql2000 .ConnectionString(c => .... ) .Cache(c => c.UseQueryCache().ProviderClass<HashtableCacheProvider>()) .Dialect<NordicMsSql2000Dialect>() ) .Mappings(m => ....) .BuildConfiguration(); When calling recent_date() I get the following error: System.Data.SqlClient.SqlException: 'recent_date' is not a recognized function name I'm using it in a where statement for a HasMany-mapping like below. HasMany(x => x.RecentValues) .Access.CamelCaseField(Prefix.Underscore) .Cascade.SaveUpdate() .Where("Date >= recent_date()"); What am I missing here?

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  • Select a row having a column with max value - On a date range

    - by Abhi
    Excuse me for posting a similar question. Please consider this: date value 18/5/2010, 1 pm 40 18/5/2010, 2 pm 20 18/5/2010, 3 pm 60 18/5/2010, 4 pm 30 18/5/2010, 5 pm 60 18/5/2010, 6 pm 25 19/5/2010, 6 pm 300 19/5/2010, 6 pm 450 19/5/2010, 6 pm 375 20/5/2010, 6 pm 250 20/5/2010, 6 pm 310 The query is to get the date and value for each day such that the value obtained for that day is max. If the max value is repeated on that day, the lowest time stamp is selected. The result should be like: 18/5/2010, 3 pm 60 19/5/2010, 6 pm 450 20/5/2010, 6 pm 310 The query should take in a date range like the one given below and find results for that range in the above fashion: where date = to_date('26/03/2010','DD/MM/YYYY') AND date < to_date('27/03/2010','DD/MM/YYYY')

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  • Looking for books

    - by robblot
    When I was learning Visual Basic.net 2008 I found a book that not only taught the basics but by the end of the book I had developed a fully working database application. Does anyone know where I might find a simular book but using Visual C++?

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  • Native XML WebService With Authentication Basic and SSL

    - by tom
    I'm using 2005 and the Native XML WebServices. The integrated authentication via HTTP:80 works fine. But i need the basic authentication which requires SSL. So if i change the web service to ssl i always get a connection reset (101). I tried several ports 80,443,9999 with the same outcome. What is the error?

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  • Timeout LinqToSql inserting millions of records

    - by Bas
    I'm inserting approximently 3 million records in a database using this solution. Eventually when the application has been inserting records for a while (my last run lasted around 4 hours), it gives a timeout with the following SqlException: "SqlExcepetion: Timeout expired. The timeoutperiod elapsed prior to completion of the operation or the server is not responding." What's the best way to handle this exception? Is there a way to prevent this from happening or should I catch the exception? Thanks in advance!

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  • Removing "Using temporary; Using filesort" from this MySQL select+join+group by query

    - by claytontstanley
    I have the following query: select t.Chunk as LeftChunk, t.ChunkHash as LeftChunkHash, q.Chunk as RightChunk, q.ChunkHash as RightChunkHash, count(t.ChunkHash) as ChunkCount from chunksubset as t join chunksubset as q on t.ID = q.ID group by LeftChunkHash, RightChunkHash And the following explain table: id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE subsets ref PRIMARY,IDIndex,SubsetIndex SubsetIndex 767 const 522014 "Using where; Using temporary; Using filesort" 1 SIMPLE subsets eq_ref PRIMARY,IDIndex,SubsetIndex PRIMARY 771 sotero.subsets.Id,const 1 "Using where; Using index" 1 SIMPLE c ref IDIndex IDIndex 4 sotero.subsets.Id 12 "Using where" 1 SIMPLE c ref IDIndex IDIndex 4 sotero.subsets.Id 12 note the "using temporary; using filesort". When this query is run, I quickly run out of RAM (presumably b/c of the temp table), and then the HDD kicks in, and the query slows to a halt. I thought it might be an index issue, so I started adding a few that sort of made sense: Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment chunks 0 PRIMARY 1 ChunkId A 17796190 NULL NULL BTREE chunks 1 ChunkHashIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 IDIndex 1 Id A 1483015 NULL NULL BTREE chunks 1 ChunkIndex 1 Chunk A 243783 NULL NULL BTREE chunks 1 ChunkTypeIndex 1 ChunkType A 2 NULL NULL BTREE chunks 1 chunkHashByChunkIDIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 chunkHashByChunkIDIndex 2 ChunkId A 17796190 NULL NULL BTREE chunks 1 chunkHashByChunkTypeIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 chunkHashByChunkTypeIndex 2 ChunkType A 261708 NULL NULL BTREE chunks 1 chunkHashByIDIndex 1 ChunkHash A 243783 NULL NULL BTREE chunks 1 chunkHashByIDIndex 2 Id A 17796190 NULL NULL BTREE But still using the temporary table. The db engine is MyISAM. How can I get rid of the using temporary; using filesort in this query? Just changing to InnoDB w/o explaining the underlying cause is not a particularly satisfying answer. Besides, if the solution is to just add the proper index, then that's much easier than migrating to another db engine.

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  • count(*) is it really expensive ?

    - by Anil Namde
    I have a page where i have 4 tabs displaying 4 different reports based of different tables. Now i get row count of each tabled using select count() from table query and display number of rows available in each table on the tabs. Now with each page post back 5 count() queries are executed (4 to get counts and 1 for pagination) and 1 query for getting report. Now my question is should is count(*) query really expensive that i should keep the row counts (at least which are displayed on tab) in view state of page instead of queering each time? How much expensive it is ?

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  • SSAS dimension source table changed - how to propagate changes to analysis server?

    - by Phil
    Hi, Sorry if the question isn't phrased very well but I'm new to SSAS and don't know the correct terms. I have changed the name of a table and its columns. I am using said table as a dimension for my cube, so now the cube won't process. Presumably I need to make updates in the analysis server to reflect changes to the source database? I have no idea where to start - any help gratefully received. Thanks Phil

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  • LINQ Group By to project into a non-anonymous type?

    - by vikp
    Hi, I have the following LINQ example: var colorDistribution = from product in ctx.Products group product by product.Color into productColors select new { Color = productColors.Key, Count = productColors.Count() }; All this works and makes perfect sense. What I'm trying to achieve is to group by into a strong type instead of anonymous type. For example I have a ProductColour class and I would like to Group into a List<ProductColour> Is this possible? Thank you

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  • Where to store site settings: DB? XML? CONFIG? CLASS FILES?

    - by Emin
    I am re-building a news portal of which already have a large number of visits every day. One of the major concerns when re-building this site was to maximize performance and speed. Having said this, we have done many things from caching, to all sort of other measures to ensure speed. Now towards the end of the project, I am having a dilemma of where to store my site settings that would least affect performance. The site settings will include things such as: Domain, DefaultImgPath, Google Analytics code, default emails of editors as well as more dynamic design/display feature settings such as the background color of specific DIVs and default color for links etc.. As far as I know, I have 4 choices in storing all these info. Database: Storing general settings in the DB and caching them may be a solution however, I want to limit the access to the database for only necessary and essential functions of the project which generally are insert/update/delete news items, author articles etc.. XML: I can store these settings in an XML file but I have not done this sort of thing before so I don't know what kind of problems -if any- I might face in the future. CONFIG: I can also store these settings in web.config CLASS FILE: I can hard code all these settings in a SiteSettings class, but since the site admin himself will be able to edit these settings, It may not be the best solution. Currently, I am more close to choosing web.config but letting people fiddle with it too often is something I do not want. E.g. if somehow, I miss out a validation for something and it breaks the web.config, the whole site will go down. My concern basically is that, I cannot forsee any possible consequences of using any of the methods above (or is there any other?), I was hoping to get this question over to more experienced people out here who hopefully help make my decision.

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  • Update a list of things without hitting every entry

    - by bobobobo
    I have a list in a database that the user should be able to order. itemname| order value (int) --------+--------------------- salad | 1 mango | 2 orange | 3 apples | 4 On load from the database, I simply order by order_value. By drag 'n drop, he should be able to move apples so that it appears at the top of the list.. itemname| order value (int) --------+--------------------- apples | 4 salad | 1 mango | 2 orange | 3 Ok. So now internally I have to update EVERY LIST ITEM! If the list has 20 or 100 items, that's a lot of updates for a simple drag operation. itemname| order value (int) --------+--------------------- apples | 1 salad | 2 mango | 3 orange | 4 I'd rather do it with only one update. One way I thought of is if "internal Order" is a double value. itemname| order value (double) --------+--------------------- salad | 1.0 mango | 2.0 orange | 3.0 apples | 4.0 SO after the drag n' drop operation, I assign apples has a value that is less than the item it is to appear in front of: itemname| order value (double) --------+--------------------- apples | 0.5 salad | 1.0 mango | 2.0 orange | 3.0 .. and if an item is dragged into the middle somewhere, its order_value is bigger than the one it appears after .. here I moved orange to be between salad and mango: itemname| order value (double) --------+--------------------- apples | 0.5 salad | 1.0 orange | 1.5 mango | 2.0 Any thoughts on better ways to do this?

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  • Is there a problem when I call SqlAdapter.Update and at the same time call SqlDataReader.Read

    - by Ahmed Said
    I have two applications, one updates a single table which has constant number of rows (128 rows) using SqlDataAdapter.Update method , and another application that select from this table periodically using SqlDataReader. sometimes the DataReader returns only 127 rows not 128, and the update application does not remove or even insert any new rows, it just update. I am asking what is the cause of this behaviour?

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  • Wordpress Database SQL query help needed

    - by i-CONICA
    Hi, I've written a PHP script to access the latest item from the wordpress database, which it does. But I need to use it twice, once for the latest item from a specific category, and another from a differerent category... But right now I cannot figure out how to put the query together. The post has a post_parent, which in another table, called wp_term_relationships, is referred to as object_id, and has a term_taxonomy_id, which then relates to a different table, called wp_terms where the term_taxonomy_id is now term_id and then you have the category slug name available to select... I really cannot understand how this query would work though. I've made a really crap mock up of it, to try to "visually" explain what i'm trying to do... SELECT * FROM wp_posts WHERE post_status = 'publish' AND (SELECT term_taxonomy_id FROM wp_term_relationships WHERE object_id = post_parent) AND (SELECT slug FROM wp_terms WHERE term_id = term_taxonomy_id) ORDER BY ID DESC LIMIT 1 Really would appreciate some help... Thanks.

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  • Oracle query to select rows with unique code

    - by Jasim
    I have a table like this C1 C2 C3 Code 1 2 3 33 1 2 3 34 2 4 1 14 1 2 3 14 i want to select only those record whose code is appearing only in single row. ie, in this case rows with code 33 and 34.. as they appear only once in this table. How can i write a query for that

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  • Meaning of tA tC and tP

    - by Greg Wiley
    If this is a duplicate I appoligize, but looking for two-letter strings is quite hard in any search. I'm looking for the meaning of tA tC and tP in the context of a mysql query. And in the spirit of "teaching a man how to fish" it would be great if you could point me in the right direction of where to find this info in the future. Edit: The Query $wpdb->get_row($wpdb->prepare("SELECT tA.* FROM ".AMYLITE_ADS." tA, ".AMYLITE_ADS_CAMPAIGNS." tC, ".AMYLITE_PACKAGES." tP WHERE tA.id=tC.ad_id AND tC.campaign_id=tP.campaign_id AND tP.zone_id=%d AND tP.date_end>CURDATE() GROUP BY tA.id ORDER BY RAND()", $zone->id));

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