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  • SQL Spatial: Getting “nearest” calculations working properly

    - by Rob Farley
    If you’ve ever done spatial work with SQL Server, I hope you’ve come across the ‘nearest’ problem. You have five thousand stores around the world, and you want to identify the one that’s closest to a particular place. Maybe you want the store closest to the LobsterPot office in Adelaide, at -34.925806, 138.605073. Or our new US office, at 42.524929, -87.858244. Or maybe both! You know how to do this. You don’t want to use an aggregate MIN or MAX, because you want the whole row, telling you which store it is. You want to use TOP, and if you want to find the closest store for multiple locations, you use APPLY. Let’s do this (but I’m going to use addresses in AdventureWorks2012, as I don’t have a list of stores). Oh, and before I do, let’s make sure we have a spatial index in place. I’m going to use the default options. CREATE SPATIAL INDEX spin_Address ON Person.Address(SpatialLocation); And my actual query: WITH MyLocations AS (SELECT * FROM (VALUES ('LobsterPot Adelaide', geography::Point(-34.925806, 138.605073, 4326)),                        ('LobsterPot USA', geography::Point(42.524929, -87.858244, 4326))                ) t (Name, Geo)) SELECT l.Name, a.AddressLine1, a.City, s.Name AS [State], c.Name AS Country FROM MyLocations AS l CROSS APPLY (     SELECT TOP (1) *     FROM Person.Address AS ad     ORDER BY l.Geo.STDistance(ad.SpatialLocation)     ) AS a JOIN Person.StateProvince AS s     ON s.StateProvinceID = a.StateProvinceID JOIN Person.CountryRegion AS c     ON c.CountryRegionCode = s.CountryRegionCode ; Great! This is definitely working. I know both those City locations, even if the AddressLine1s don’t quite ring a bell. I’m sure I’ll be able to find them next time I’m in the area. But of course what I’m concerned about from a querying perspective is what’s happened behind the scenes – the execution plan. This isn’t pretty. It’s not using my index. It’s sucking every row out of the Address table TWICE (which sucks), and then it’s sorting them by the distance to find the smallest one. It’s not pretty, and it takes a while. Mind you, I do like the fact that it saw an indexed view it could use for the State and Country details – that’s pretty neat. But yeah – users of my nifty website aren’t going to like how long that query takes. The frustrating thing is that I know that I can use the index to find locations that are within a particular distance of my locations quite easily, and Microsoft recommends this for solving the ‘nearest’ problem, as described at http://msdn.microsoft.com/en-au/library/ff929109.aspx. Now, in the first example on this page, it says that the query there will use the spatial index. But when I run it on my machine, it does nothing of the sort. I’m not particularly impressed. But what we see here is that parallelism has kicked in. In my scenario, it’s split the data up into 4 threads, but it’s still slow, and not using my index. It’s disappointing. But I can persuade it with hints! If I tell it to FORCESEEK, or use my index, or even turn off the parallelism with MAXDOP 1, then I get the index being used, and it’s a thing of beauty! Part of the plan is here: It’s massive, and it’s ugly, and it uses a TVF… but it’s quick. The way it works is to hook into the GeodeticTessellation function, which is essentially finds where the point is, and works out through the spatial index cells that surround it. This then provides a framework to be able to see into the spatial index for the items we want. You can read more about it at http://msdn.microsoft.com/en-us/library/bb895265.aspx#tessellation – including a bunch of pretty diagrams. One of those times when we have a much more complex-looking plan, but just because of the good that’s going on. This tessellation stuff was introduced in SQL Server 2012. But my query isn’t using it. When I try to use the FORCESEEK hint on the Person.Address table, I get the friendly error: Msg 8622, Level 16, State 1, Line 1 Query processor could not produce a query plan because of the hints defined in this query. Resubmit the query without specifying any hints and without using SET FORCEPLAN. And I’m almost tempted to just give up and move back to the old method of checking increasingly large circles around my location. After all, I can even leverage multiple OUTER APPLY clauses just like I did in my recent Lookup post. WITH MyLocations AS (SELECT * FROM (VALUES ('LobsterPot Adelaide', geography::Point(-34.925806, 138.605073, 4326)),                        ('LobsterPot USA', geography::Point(42.524929, -87.858244, 4326))                ) t (Name, Geo)) SELECT     l.Name,     COALESCE(a1.AddressLine1,a2.AddressLine1,a3.AddressLine1),     COALESCE(a1.City,a2.City,a3.City),     s.Name AS [State],     c.Name AS Country FROM MyLocations AS l OUTER APPLY (     SELECT TOP (1) *     FROM Person.Address AS ad     WHERE l.Geo.STDistance(ad.SpatialLocation) < 1000     ORDER BY l.Geo.STDistance(ad.SpatialLocation)     ) AS a1 OUTER APPLY (     SELECT TOP (1) *     FROM Person.Address AS ad     WHERE l.Geo.STDistance(ad.SpatialLocation) < 5000     AND a1.AddressID IS NULL     ORDER BY l.Geo.STDistance(ad.SpatialLocation)     ) AS a2 OUTER APPLY (     SELECT TOP (1) *     FROM Person.Address AS ad     WHERE l.Geo.STDistance(ad.SpatialLocation) < 20000     AND a2.AddressID IS NULL     ORDER BY l.Geo.STDistance(ad.SpatialLocation)     ) AS a3 JOIN Person.StateProvince AS s     ON s.StateProvinceID = COALESCE(a1.StateProvinceID,a2.StateProvinceID,a3.StateProvinceID) JOIN Person.CountryRegion AS c     ON c.CountryRegionCode = s.CountryRegionCode ; But this isn’t friendly-looking at all, and I’d use the method recommended by Isaac Kunen, who uses a table of numbers for the expanding circles. It feels old-school though, when I’m dealing with SQL 2012 (and later) versions. So why isn’t my query doing what it’s supposed to? Remember the query... WITH MyLocations AS (SELECT * FROM (VALUES ('LobsterPot Adelaide', geography::Point(-34.925806, 138.605073, 4326)),                        ('LobsterPot USA', geography::Point(42.524929, -87.858244, 4326))                ) t (Name, Geo)) SELECT l.Name, a.AddressLine1, a.City, s.Name AS [State], c.Name AS Country FROM MyLocations AS l CROSS APPLY (     SELECT TOP (1) *     FROM Person.Address AS ad     ORDER BY l.Geo.STDistance(ad.SpatialLocation)     ) AS a JOIN Person.StateProvince AS s     ON s.StateProvinceID = a.StateProvinceID JOIN Person.CountryRegion AS c     ON c.CountryRegionCode = s.CountryRegionCode ; Well, I just wasn’t reading http://msdn.microsoft.com/en-us/library/ff929109.aspx properly. The following requirements must be met for a Nearest Neighbor query to use a spatial index: A spatial index must be present on one of the spatial columns and the STDistance() method must use that column in the WHERE and ORDER BY clauses. The TOP clause cannot contain a PERCENT statement. The WHERE clause must contain a STDistance() method. If there are multiple predicates in the WHERE clause then the predicate containing STDistance() method must be connected by an AND conjunction to the other predicates. The STDistance() method cannot be in an optional part of the WHERE clause. The first expression in the ORDER BY clause must use the STDistance() method. Sort order for the first STDistance() expression in the ORDER BY clause must be ASC. All the rows for which STDistance returns NULL must be filtered out. Let’s start from the top. 1. Needs a spatial index on one of the columns that’s in the STDistance call. Yup, got the index. 2. No ‘PERCENT’. Yeah, I don’t have that. 3. The WHERE clause needs to use STDistance(). Ok, but I’m not filtering, so that should be fine. 4. Yeah, I don’t have multiple predicates. 5. The first expression in the ORDER BY is my distance, that’s fine. 6. Sort order is ASC, because otherwise we’d be starting with the ones that are furthest away, and that’s tricky. 7. All the rows for which STDistance returns NULL must be filtered out. But I don’t have any NULL values, so that shouldn’t affect me either. ...but something’s wrong. I do actually need to satisfy #3. And I do need to make sure #7 is being handled properly, because there are some situations (eg, differing SRIDs) where STDistance can return NULL. It says so at http://msdn.microsoft.com/en-us/library/bb933808.aspx – “STDistance() always returns null if the spatial reference IDs (SRIDs) of the geography instances do not match.” So if I simply make sure that I’m filtering out the rows that return NULL… …then it’s blindingly fast, I get the right results, and I’ve got the complex-but-brilliant plan that I wanted. It just wasn’t overly intuitive, despite being documented. @rob_farley

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  • How big can my SharePoint 2010 installation be?

    - by Sahil Malik
    Ad:: SharePoint 2007 Training in .NET 3.5 technologies (more information). 3 years ago, I had published “How big can my SharePoint 2007 installation be?” Well, SharePoint 2010 has significant under the covers improvements. So, how big can your SharePoint 2010 installation be? There are three kinds of limits you should know about Hard limits that cannot be exceeded by design. Configurable that are, well configurable – but the default values are set for a pretty good reason, so if you need to tweak, plan and understand before you tweak. Soft limits, you can exceed them, but it is not recommended that you do. Before you read any of the limits, read these two important disclaimers - 1. The limit depends on what you’re doing. So, don’t take the below as gospel, the reality depends on your situation. 2. There are many additional considerations in planning your SharePoint solution scalability and performance, besides just the below. So with those in mind, here goes.   Hard Limits - Zones per web app 5 RBS NAS performance Time to first byte of any response from NAS must be less than 20 milliseconds List row size 8000 bytes driven by how SP stores list items internally Max file size 2GB (default is 50MB, configurable). RBS does not increase this limit. Search metadata properties 10,000 per item crawled (pretty damn high, you’ll never need to worry about it). Max # of concurrent in-memory enterprise content types 5000 per web server, per tenant Max # of external system connections 500 per web server PerformancePoint services using Excel services as a datasource No single query can fetch more than 1 million excel cells Office Web Apps Renders One doc per second, per CPU core, per Application server, limited to a maximum of 8 cores.   Configurable Limits - Row Size Limit 6, configurable via SPWebApplication.MaxListItemRowStorage property List view lookup 8 join operations per query Max number of list items that a single operation can process at one time in normal hours 5000 Configurable via SPWebApplication.MaxItemsPerThrottledOperation   Also you get a warning at 3000, which is configurable via SPWebApplication.MaxItemsPerThrottledOperationWarningLevel   In addition, throttle overrides can be requested, throttle overrides can be disabled, and time windows can be set when throttle is disabled. Max number of list items for administrators that a single operation can process at one time in normal hours 20000 Configurable via SPWebApplication.MaxItemsPerThrottledOperationOverride Enumerating subsites 2000 Word and Powerpoint co-authoring simultaneous editors 10 (Hard limit is 99). # of webparts on a page 25 Search Crawl DBs per search service app 10 Items per crawl db 25 million Search Keywords 200 per site collection. There is a max limit of 5000, which can then be modified by editing the web.config/client.config. Concurrent # of workflows on a content db 15. Workflows running in the timer service are not counted in this limit. Further workflows are queued. Can be configured via the Set-SPFarmConfig powershell commandlet. Number of events picked by the workflow timer job and delivered to workflows 100. You can increase this limit by running additional instances of the workflow timer service. Visio services file size 50MB Visio web drawing recalculation timeout 120 seconds Configurable via – Powershell commandlet Set-SPVisioPerformance Visio services minimum and maximum cache age for data connected diagrams 0 to 24 hours. Default is 60 minutes. Configurable via – Powershell commandlet Set-SPVisioPerformance   Soft Limits - Content Databases 300 per web app Application Pools 10 per web server Managed Paths 20 per web app Content Database Size 200GB per Content DB Size of 1 site collection 100GB # of sites in a site collection 250,000 Documents in a library 30 Million, with nesting. Depends heavily on type and usage and size of documents. Items 30 million. Depends heavily on usage of items. SPGroups one SPUser can be in 5000 Users in a site collection 2 million, depends on UI, nesting, containers and underlying user store AD Principals in a SPGroup 5000 SPGroups in a site collection 10000 Search Service Instances 20 Indexed Items in Search 100 million Crawl Log entries 100 million Search Alerts 1 million per search application Search Crawled Properties 1/2 million URL removals in search 100 removals per operation User Profiles 2 million per service application Social Tags 500 million per social database Comment on the article ....

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  • a more pythonic way to express conditionally bounded loop?

    - by msw
    I've got a loop that wants to execute to exhaustion or until some user specified limit is reached. I've got a construct that looks bad yet I can't seem to find a more elegant way to express it; is there one? def ello_bruce(limit=None): for i in xrange(10**5): if predicate(i): if not limit is None: limit -= 1 if limit <= 0: break def predicate(i): # lengthy computation return True Holy nesting! There has to be a better way. For purposes of a working example, xrange is used where I normally have an iterator of finite but unknown length (and predicate sometimes returns False).

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  • Problems in php coding

    - by anwar
    Hi there everyone im new to PHP and Joomla and I have developed a component in Joomla but my code is giving me errors. I have tried to solve the problem but I’am unable to solve it. So can anyone suggest me what is the problem with my code? Thanks in advance. Here are my two files: 1st view.html.php defined('_JEXEC') or die('=;)'); jimport('joomla.application.component.view'); class namnamViewlistrestaurant extends JView { function display($tpl = null) { $item = 'item'; RestUser::RestrictDirectAccess(); //-- Custom css JHTML::stylesheet( 'style.css', 'components/com_namnam/assets/css/' ); $cuisine=Lookups::getLookup('cuisine'); $lists['cuisine'] = JHTML::_('select.genericlist', $cuisine, 'idcuisine[]', 'class="inputbox" size="7"', 'value', 'text', $item->idcuisine); $category=Lookups::getLookup('restcategory'); $lists['category'] = JHTML::_('select.genericlist', $category, 'idcategory[]', 'class="inputbox" multiple="multiple" size="7"', 'value', 'text', $item->idcategory); $items = & $this->get('Data'); $pagination =& $this->get('Pagination'); $lists = & $this->get('List'); $this->assignRef('items', $items); $this->assignRef('pagination', $pagination); $this->assignRef('lists', $lists); parent::display($tpl); }//function }//class And 2nd is listrestaurant.php defined('_JEXEC') or die('=;)'); jimport('joomla.application.component.model'); class namnamModellistrestaurant extends JModel { var $_data; var $_total = null; var $_pagination = null; function __construct() { parent::__construct(); global $mainframe, $option; $limit = $mainframe->getUserStateFromRequest( 'global.list.limit', 'limit', $mainframe->getCfg('list_limit'), 'int' ); $limitstart = $mainframe->getUserStateFromRequest( $option.'.limitstart', 'limitstart', 0, 'int' ); $limitstart = ($limit != 0 ? (floor($limitstart / $limit) * $limit) : 0); $this->setState('limit', $limit); $this->setState('limitstart', $limitstart); } function _buildQuery() { $where = array(); $where[]=" idowner=".RestUser::getUserID()." "; if ($this->search) { $where[] = 'LOWER(name) LIKE \''. $this->search. '\''; } $where =( count($where) ) ? ' WHERE ' . implode( ' AND ', $where ) : ''; $orderby = ''; #_ECR_MAT_FILTER_MODEL1_ if (($this->filter_order) && ($this->filter_order_Dir)) { $orderby = ' ORDER BY '. $this->filter_order .' '. $this->filter_order_Dir; } $this->_query = ' SELECT *' . ' FROM #__namnam_restaurants ' . $where . $orderby ; return $this->_query; } function getData() { if (empty($this->_data)) { $query = $this->_buildQuery(); $this->_data = $this->_getList($query, $this->getState('limitstart'), $this->getState('limit')); } return $this->_data; } function getList() { // table ordering $lists['order_Dir'] = $this->filter_order_Dir; $lists['order'] = $this->filter_order; // search filter $lists['search']= $this->search; return $lists; } function getTotal() { // Load the content if it doesn't already exist if (empty($this->_total)) { $query = $this->_buildQuery(); $this->_total = $this->_getListCount($query); } return $this->_total; } function getPagination() { // Load the content if it doesn't already exist if (empty($this->_pagination)) { jimport('joomla.html.pagination'); $this->_pagination = new JPagination($this->getTotal(), $this->getState('limitstart'), $this->getState('limit') ); } return $this->_pagination; } }//class And the errors are: Notice: Trying to get property of non-object in C:\wamp\www\namnam.com\components\com_namnam\views\listrestaurant\view.html.php on line 26 Notice: Trying to get property of non-object in C:\wamp\www\namnam.com\components\com_namnam\views\listrestaurant\view.html.php on line 29 Notice: Undefined property: namnamModellistrestaurant::$search in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 38 Notice: Undefined property: namnamModellistrestaurant::$filter_order in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 48 Notice: Undefined property: namnamModellistrestaurant::$search in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 38 Notice: Undefined property: namnamModellistrestaurant::$filter_order in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 48 Notice: Undefined property: namnamModellistrestaurant::$filter_order_Dir in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 76 Notice: Undefined property: namnamModellistrestaurant::$filter_order in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 77 Notice: Undefined property: namnamModellistrestaurant::$search in C:\wamp\www\namnam.com\components\com_namnam\models\listrestaurant.php on line 80

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  • Problem with keyPress in Mozilla

    - by sudhansu
    I am usingtextarea to get some inputs. A label shows the updated chars left. It works fine in IE, but in FF 3.0, after reaching the max limit, it doesn't allow to delete or backspace key. I am using a javascript function on keypress event of the textarea. the javascript code is function checkLength() { var opinion = document.getElementById('opinion').value; if(opinion.length > 50) alert("You have reached the mas limit."); else document.getElementById('limit').innerHTML = 50 - opinion.length; } while on the page, i am using this <label id="limit">50 </label> <textarea id="opTxtArea" onkeypress="javascript:checkLength();"></textarea> Everything is working fine. The problem arises in FF, when the inputs reach the max limit, the message is displayed, but it doesn't allow to delete or backspace.

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  • SQL Server - Storing multiple decimal values in a column?

    - by cshah
    I know storing multiple values in a column. Not a good idea. It violates first normal form --- which states NO multi valued attributes. Normalize period... I am using SQL Server 2005 I have a table that require to store lower limit and uppper limit for a measurement, think of it as a minimum and maximum speed limit... only problem is only 2 % out of hundread i need upper limit. I will only have data for lower limit. I was thinking to store both values in a column (Sparse column introduces in 2008 so not for me) Is there a way...? Not sure about XML..

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  • SQL Server: Cross-tabulation, please help

    - by user335160
    I want to achieve the results shown in the attached image. The table structure and data are: Table relationship: Facility Limit -> one to many -> Facility Sub Limit Tables structure and data Facility Limit Id OverallIBLimitId Product Type 1 1 RPA 2 1 CG 3 2 RPA 4 3 CG Facility Sub Limit Id FacilityLimitId Sub-Limit Type Amount Tenor Status Status Date 1 1 RPA at max 2,000,0000.00 2 months Approved January 5, 2011 2 1 Oil 3,000,0000.00 3 yrs Approved January 5, 2011 3 2 CG at minor 4,000,0000.00 1 yr Approved January 5, 2011 4 2 CG at max 5,000,0000.00 6 months Approved January 5, 2011 5 2 Flood Component 1 5,000,0000.00 6 months Approved January 5, 2011 6 2 Flood Component 2 6,000,0000.00 3 yrs Approved January 5, 2011 7 3 RPA at minor 1,000,0000.00 6 months Approved January 5, 2011 8 4 One-Off 1,000,0000.00 6 months Approved January 5, 2011

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  • Using php variable inside a query

    - by Aruna
    Hi, i am using a query inside php as $query = 'SELECT * from #__chronoforms_UploadAuthor where text_6 like "%'.$_GET['title'].'%" and text_7 like "%'.$_GET['author'].'%" limit 0,1'; where i am trying to insert a php variable instead of 1 in the limit.. $query = 'SELECT * from #__chronoforms_UploadAuthor where text_6 like "%'.$_GET['title'].'%" and text_7 like "%'.$_GET['author'].'%" limit 0,"'.$_GET['limit'].'"'; but it shows me the error . Pls help me .. THere are some errors in keeping $_GET['limit']..

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  • Union - Same table, excluding previous results MySQL

    - by user82302124
    I'm trying to write a query that will: Run a query, give me (x) number of rows (limit 4) If that query didn't give me the 4 I need, run a second query limit 4-(x) and exclude the ids from the first query A third query that acts like the second I have this: (SELECT *, 1 as SORY_QUERY1 FROM xbamZ where state = 'Minnesota' and industry = 'Miscellaneous' and id != '229' limit 4) UNION (SELECT *, 2 FROM xbamZ where state = 'Minnesota' limit 2) UNION (SELECT *, 3 FROM xbamZ where industry = 'Miscellaneous' limit 1) How (or is?) do I do that? Am I close? This query gives me duplicates

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  • Setting an attribute in Jquery not working

    - by Probocop
    Hi, I have the following function which limits the amount of characters you can enter into a text area. What's meant to happen is, if the text length is higher than the text limit, set an attribute of disabled="disabled" on the submit button, but it isn't getting set, my function code is as follows: function limitChars(textid, limit, infodiv) { var text = $('#'+textid).val(); var textlength = text.length; if(textlength > limit) { $('#' + infodiv).html('You cannot write more then '+limit+' characters!'); $('input#submit').attr('disabled', 'disabled'); } else { $('#' + infodiv).html('You have '+ (limit - textlength) +' characters left.'); } } Any ideas?

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  • Analytic functions – they’re not aggregates

    - by Rob Farley
    SQL 2012 brings us a bunch of new analytic functions, together with enhancements to the OVER clause. People who have known me over the years will remember that I’m a big fan of the OVER clause and the types of things that it brings us when applied to aggregate functions, as well as the ranking functions that it enables. The OVER clause was introduced in SQL Server 2005, and remained frustratingly unchanged until SQL Server 2012. This post is going to look at a particular aspect of the analytic functions though (not the enhancements to the OVER clause). When I give presentations about the analytic functions around Australia as part of the tour of SQL Saturdays (starting in Brisbane this Thursday), and in Chicago next month, I’ll make sure it’s sufficiently well described. But for this post – I’m going to skip that and assume you get it. The analytic functions introduced in SQL 2012 seem to come in pairs – FIRST_VALUE and LAST_VALUE, LAG and LEAD, CUME_DIST and PERCENT_RANK, PERCENTILE_CONT and PERCENTILE_DISC. Perhaps frustratingly, they take slightly different forms as well. The ones I want to look at now are FIRST_VALUE and LAST_VALUE, and PERCENTILE_CONT and PERCENTILE_DISC. The reason I’m pulling this ones out is that they always produce the same result within their partitions (if you’re applying them to the whole partition). Consider the following query: SELECT     YEAR(OrderDate),     FIRST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING),     LAST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING),     PERCENTILE_CONT(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)),     PERCENTILE_DISC(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)) FROM Sales.SalesOrderHeader ; This is designed to get the TotalDue for the first order of the year, the last order of the year, and also the 95% percentile, using both the continuous and discrete methods (‘discrete’ means it picks the closest one from the values available – ‘continuous’ means it will happily use something between, similar to what you would do for a traditional median of four values). I’m sure you can imagine the results – a different value for each field, but within each year, all the rows the same. Notice that I’m not grouping by the year. Nor am I filtering. This query gives us a result for every row in the SalesOrderHeader table – 31465 in this case (using the original AdventureWorks that dates back to the SQL 2005 days). The RANGE BETWEEN bit in FIRST_VALUE and LAST_VALUE is needed to make sure that we’re considering all the rows available. If we don’t specify that, it assumes we only mean “RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW”, which means that LAST_VALUE ends up being the row we’re looking at. At this point you might think about other environments such as Access or Reporting Services, and remember aggregate functions like FIRST. We really should be able to do something like: SELECT     YEAR(OrderDate),     FIRST_VALUE(TotalDue)         OVER (PARTITION BY YEAR(OrderDate)               ORDER BY OrderDate, SalesOrderID               RANGE BETWEEN UNBOUNDED PRECEDING                         AND UNBOUNDED FOLLOWING) FROM Sales.SalesOrderHeader GROUP BY YEAR(OrderDate) ; But you can’t. You get that age-old error: Msg 8120, Level 16, State 1, Line 5 Column 'Sales.SalesOrderHeader.OrderDate' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Msg 8120, Level 16, State 1, Line 5 Column 'Sales.SalesOrderHeader.SalesOrderID' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. Hmm. You see, FIRST_VALUE isn’t an aggregate function. None of these analytic functions are. There are too many things involved for SQL to realise that the values produced might be identical within the group. Furthermore, you can’t even surround it in a MAX. Then you get a different error, telling you that you can’t use windowed functions in the context of an aggregate. And so we end up grouping by doing a DISTINCT. SELECT DISTINCT     YEAR(OrderDate),         FIRST_VALUE(TotalDue)              OVER (PARTITION BY YEAR(OrderDate)                   ORDER BY OrderDate, SalesOrderID                   RANGE BETWEEN UNBOUNDED PRECEDING                             AND UNBOUNDED FOLLOWING),         LAST_VALUE(TotalDue)             OVER (PARTITION BY YEAR(OrderDate)                   ORDER BY OrderDate, SalesOrderID                   RANGE BETWEEN UNBOUNDED PRECEDING                             AND UNBOUNDED FOLLOWING),     PERCENTILE_CONT(0.95)          WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)),     PERCENTILE_DISC(0.95)         WITHIN GROUP (ORDER BY TotalDue)         OVER (PARTITION BY YEAR(OrderDate)) FROM Sales.SalesOrderHeader ; I’m sorry. It’s just the way it goes. Hopefully it’ll change the future, but for now, it’s what you’ll have to do. If we look in the execution plan, we see that it’s incredibly ugly, and actually works out the results of these analytic functions for all 31465 rows, finally performing the distinct operation to convert it into the four rows we get in the results. You might be able to achieve a better plan using things like TOP, or the kind of calculation that I used in http://sqlblog.com/blogs/rob_farley/archive/2011/08/23/t-sql-thoughts-about-the-95th-percentile.aspx (which is how PERCENTILE_CONT works), but it’s definitely convenient to use these functions, and in time, I’m sure we’ll see good improvements in the way that they are implemented. Oh, and this post should be good for fellow SQL Server MVP Nigel Sammy’s T-SQL Tuesday this month.

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  • EJB Named Criteria - Apply bind variable in Backingbean

    - by Deepak Siddappa
    EJB Named criteria are predefined and reusable where-clause definitions that are dynamically applied to a ViewObject query. Here we often use to filter the ViewObject SQL statement query based on Where Clause conditions.Take a scenario where we need to filter the SQL statements query based on Where Clause conditions, instead of playing with SQL statements use the EJB Named Criteria which is supported by default in ADF and set the Bind Variable parameter at run time.You can download the sample workspace from here [Runs with Oracle JDeveloper 11.1.2.0.0 (11g R2) + HR Schema] Implementation StepsCreate Java EE Web Application with entity based on Employees table, then create a session bean and data control for the session bean.Open the DataControls.dcx file and create sparse xml for as shown below. In sparse xml navigate to Named criteria tab -> Bind Variable section, create binding variable deptId. Now create a named criteria and map the query attributes to the bind variable. In the ViewController create index.jspx page, from data control palette drop employeesFindAll->Named Criteria->EmployeesCriteria->Table as ADF Read-Only Filtered Table and create the backingBean as "IndexBean".Open the index.jspx page and remove the "filterModel" binding from the table, add <af:inputText />, command button and bind them to backingBean. For command button create the actionListener as "applyEmpCriteria" and add below code to the file. public void applyEmpCriteria(ActionEvent actionEvent) { DCIteratorBinding dc = (DCIteratorBinding)evaluteEL("#{bindings.employeesFindAllIterator}"); ViewObject vo = dc.getViewObject(); vo.applyViewCriteria(vo.getViewCriteriaManager().getViewCriteria("EmployeesCriteria")); vo.ensureVariableManager().setVariableValue("deptId", this.getDeptId().getValue()); vo.executeQuery(); } /** * Programmtic evaluation of EL * * @param el EL to evalaute * @return Result of the evalutaion */ public Object evaluteEL(String el) { FacesContext fctx = FacesContext.getCurrentInstance(); ELContext elContext = fctx.getELContext(); Application app = fctx.getApplication(); ExpressionFactory expFactory = app.getExpressionFactory(); ValueExpression valExp = expFactory.createValueExpression(elContext, el, Object.class); return valExp.getValue(elContext); } Run the index.jspx page, enter departmentId value as 90 and click in ApplyEmpCriteria button. Now the bind variable for the Named criteria will be applied at runtime in the backing bean and it will re-execute ViewObject query to filter based on where clause condition.

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  • Subterranean IL: Exception handling 1

    - by Simon Cooper
    Today, I'll be starting a look at the Structured Exception Handling mechanism within the CLR. Exception handling is quite a complicated business, and, as a result, the rules governing exception handling clauses in IL are quite strict; you need to be careful when writing exception clauses in IL. Exception handlers Exception handlers are specified using a .try clause within a method definition. .try <TryStartLabel> to <TryEndLabel> <HandlerType> handler <HandlerStartLabel> to <HandlerEndLabel> As an example, a basic try/catch block would be specified like so: TryBlockStart: // ... leave.s CatchBlockEndTryBlockEnd:CatchBlockStart: // at the start of a catch block, the exception thrown is on the stack callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) leave.s CatchBlockEnd CatchBlockEnd: // method code continues... .try TryBlockStart to TryBlockEnd catch [mscorlib]System.Exception handler CatchBlockStart to CatchBlockEnd There are four different types of handler that can be specified: catch <TypeToken> This is the standard exception catch clause; you specify the object type that you want to catch (for example, [mscorlib]System.ArgumentException). Any object can be thrown as an exception, although Microsoft recommend that only classes derived from System.Exception are thrown as exceptions. filter <FilterLabel> A filter block allows you to provide custom logic to determine if a handler block should be run. This functionality is exposed in VB, but not in C#. finally A finally block executes when the try block exits, regardless of whether an exception was thrown or not. fault This is similar to a finally block, but a fault block executes only if an exception was thrown. This is not exposed in VB or C#. You can specify multiple catch or filter handling blocks in each .try, but fault and finally handlers must have their own .try clause. We'll look into why this is in later posts. Scoped exception handlers The .try syntax is quite tricky to use; it requires multiple labels, and you've got to be careful to keep separate the different exception handling sections. However, starting from .NET 2, IL allows you to use scope blocks to specify exception handlers instead. Using this syntax, the example above can be written like so: .try { // ... leave.s EndSEH}catch [mscorlib]System.Exception { callvirt instance string [mscorlib]System.Object::ToString() call void [mscorlib]System.Console::WriteLine(string) leave.s EndSEH}EndSEH:// method code continues... As you can see, this is much easier to write (and read!) than a stand-alone .try clause. Next time, I'll be looking at some of the restrictions imposed by SEH on control flow, and how the C# compiler generated exception handling clauses.

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  • SQL SERVER Convert IN to EXISTS Performance Talk

    In recent training one of the attendee asked if I can show simple method to convert IN clause to EXISTS clause. Here is the simple example. USE AdventureWorks GO --useof= SELECT * FROM HumanResources.EmployeeE WHERE E.EmployeeID = ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddressEA WHERE EA.EmployeeID = E.EmployeeID) GO --useofexists SELECT * FROM HumanResources.EmployeeE WHERE EXISTS( SELECT [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Merging two Regular Expressions to Truncate Words in Strings

    - by Alix Axel
    I'm trying to come up with the following function that truncates string to whole words (if possible, otherwise it should truncate to chars): function Text_Truncate($string, $limit, $more = '...') { $string = trim(html_entity_decode($string, ENT_QUOTES, 'UTF-8')); if (strlen(utf8_decode($string)) > $limit) { $string = preg_replace('~^(.{1,' . intval($limit) . '})(?:\s.*|$)~su', '$1', $string); if (strlen(utf8_decode($string)) > $limit) { $string = preg_replace('~^(.{' . intval($limit) . '}).*~su', '$1', $string); } $string .= $more; } return trim(htmlentities($string, ENT_QUOTES, 'UTF-8', true)); } Here are some tests: // Iñtërnâtiônàlizætiøn and then the quick brown fox... (49 + 3 chars) echo dyd_Text_Truncate('Iñtërnâtiônàlizætiøn and then the quick brown fox jumped overly the lazy dog and one day the lazy dog humped the poor fox down until she died.', 50, '...'); // Iñtërnâtiônàlizætiøn_and_then_the_quick_brown_fox_... (50 + 3 chars) echo dyd_Text_Truncate('Iñtërnâtiônàlizætiøn_and_then_the_quick_brown_fox_jumped_overly_the_lazy_dog and one day the lazy dog humped the poor fox down until she died.', 50, '...'); They both work as it is, however if I drop the second preg_replace() I get the following: Iñtërnâtiônàlizætiøn_and_then_the_quick_brown_fox_jumped_overly_the_lazy_dog and one day the lazy dog humped the poor fox down until she died.... I can't use substr() because it only works on byte level and I don't have access to mb_substr() ATM, I've made several attempts to join the second regex with the first one but without success. Please help S.M.S., I've been struggling with this for almost an hour. EDIT: I'm sorry, I've been awake for 40 hours and I shamelessly missed this: $string = preg_replace('~^(.{1,' . intval($limit) . '})(?:\s.*|$)?~su', '$1', $string); Still, if someone has a more optimized regex (or one that ignores the trailing space) please share: "Iñtërnâtiônàlizætiøn and then " "Iñtërnâtiônàlizætiøn_and_then_" EDIT 2: I still can't get rid of the trailing whitespace, can someone help me out?

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  • Jquery and PHP function

    - by Sergio
    How can I this PHP function include in jquery .html? PHP function: function trim_text($string, $limit, $break="<", $pad=" ...") { $words = explode(' ', htmlentities(strip_tags($string))); $countr = count($words); if ($countr <= 8) { return $string; }else{ // return with no change if string is shorter than $limit if(strlen($string) <= $limit) return $string; $string = substr($string, 0, $limit); if(false !== ($breakpoint = strpos($string, $break, $limit))) { if($breakpoint < strlen($string) - 1) { $string = substr($string, 0, $breakpoint) . $pad; } } $last_space = strrpos(substr($string, 0, $limit), ' '); $string = substr($string, 0, $last_space); $string = strip_tags($string); return $string.$pad; } } And the Jquery part of code where I want to in ".html" part somehow call this function is: $(" .text").html('<div>'+ message +'</div>'); What I want to do is trim this "message" text using PHP function. Is it possible?

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  • Good Starting Points for Optimizing Database Calls in Ruby on Rails?

    - by viatropos
    I have a menu in Rails which grabs a nested tree of Post models, each which have a Slug model associated via a polymorphic association (using the friendly_id gem for slugs and awesome_nested_set for the tree). The database output in development looks like this (here's the full gist): SQL (0.4ms) SELECT COUNT(*) AS count_id FROM "posts" WHERE ("posts".parent_id = 39) CACHE (0.0ms) SELECT "posts".* FROM "posts" WHERE ("posts"."id" = 13) LIMIT 1 CACHE (0.0ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 13 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 Slug Load (0.4ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 40 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 SQL (0.3ms) SELECT COUNT(*) AS count_id FROM "posts" WHERE ("posts".parent_id = 40) CACHE (0.0ms) SELECT "posts".* FROM "posts" WHERE ("posts"."id" = 13) LIMIT 1 CACHE (0.0ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 13 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 Slug Load (0.4ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 41 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 ... Rendered shared/_menu.html.haml (907.6ms) What are some quick things I should always do to optimize this from the start (easy things)? Some things I'm thinking now are: Can Rails 3 eager load the whole Post tree + associated Slugs in one DB call? Can I do that easily with named scopes or custom SQL? What is best practice in this situation? Not really thinking about memcached in this situation as that can be applied to much more than just this.

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  • Shell script task status monitoring

    - by Bikram Agarwal
    I'm running an ANT task in background and checking in 60 second intervals whether that task is complete or not. If it is not, every 60 seconds, a message should be displayed on screen - "Deploy process is still running. $slept seconds since deploy started", where $slept is 60, 120, 180 n so on. There's a limit of 1200 seconds, after which the script will show the log via 'ant log' command and ask the user whether to continue. If the user chooses to continue, 300 seconds are added to the time limit and the process repeats. The code that I am using for this task is - ant deploy & limit=1200 deploy_check() { while [ ${slept:-0} -le $limit ]; do sleep 60 && slept=`expr ${slept:-0} + 60` if [ $$ = "`ps -o ppid= -p $!`" ]; then echo "Deploy process is still running. $slept seconds since deploy started." else wait $! && echo "Application ${New_App_Name} deployed successfully" || echo "Deployment of ${New_App_Name} failed" break fi done } deploy_check if [ $$ = "`ps -o ppid= -p $!`" ]; then echo "Deploy process did not finish in $slept seconds. Here's the log." ant log echo "Do you want to kill the process? Press Ctrl+C to kill. Press Enter to continue." read log limit=`expr ${limit} + 300` deploy_check fi Now, the problem is - this code is not working. This looks like a perfectly good code and yet, this is not working. Can anyone point out what is wrong with this code, please.

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  • Is this a good starting point for iptables in Linux?

    - by sbrattla
    Hi, I'm new to iptables, and i've been trying to put together a firewall which purpose is to protect a web server. The below rules are the ones i've put together so far, and i would like to hear if the rules makes sense - and wether i've left out anything essential? In addition to port 80, i also need to have port 3306 (mysql) and 22 (ssh) open for external connections. Any feedback is highly appreciated! #!/bin/sh # Clear all existing rules. iptables -F # ACCEPT connections for loopback network connection, 127.0.0.1. iptables -A INPUT -i lo -j ACCEPT # ALLOW established traffic iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # DROP packets that are NEW but does not have the SYN but set. iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP # DROP fragmented packets, as there is no way to tell the source and destination ports of such a packet. iptables -A INPUT -f -j DROP # DROP packets with all tcp flags set (XMAS packets). iptables -A INPUT -p tcp --tcp-flags ALL ALL -j DROP # DROP packets with no tcp flags set (NULL packets). iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP # ALLOW ssh traffic (and prevent against DoS attacks) iptables -A INPUT -p tcp --dport ssh -m limit --limit 1/s -j ACCEPT # ALLOW http traffic (and prevent against DoS attacks) iptables -A INPUT -p tcp --dport http -m limit --limit 5/s -j ACCEPT # ALLOW mysql traffic (and prevent against DoS attacks) iptables -A INPUT -p tcp --dport mysql -m limit --limit 25/s -j ACCEPT # DROP any other traffic. iptables -A INPUT -j DROP

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  • Numbered paragraphs in Word 2007

    - by Kit
    I have the following styles defined in Word 2007. They all have outline levels 1-6. They also correctly show up in the Table of Contents (not all, I only set the TOC up to Level 3). 1 Heading 1 1.1 Heading 2 1.1.1 Heading 3 1.1.1.1 Heading 4 1.1.1.1.1 Heading 5 1.1.1.1.1.1 Heading 6 This is what I want 1 Heading 1 1.1 Body text under Heading Level 1 1.2 Body text under Heading Level 1 2 Heading 1 2.1 Heading 2 2.1.1 Body text under Heading Level 2 2.1.2 Body text under Heading Level 2 2.1.3 Body text under Heading Level 2 2.2 Heading 2 2.2.1 Body text under Heading Level 2 2.2.2 Body text under Heading Level 2 How do I make two list sequences link to each other? Here's a {fill in the blanks} illustration: {section number} Heading 1 {section number}.{clause number} Body text under Heading Level 1 {section number}.{clause number} Body text under Heading Level 1 The example above should expand to: 1 Heading 1 1.1 Body text under Heading Level 1 1.2 Body text under Heading Level 1 Another example: {section number} Heading 1 {section number}.{subsection number} Heading 2 {section number}.{subsection number}.{clause number} Body text under Heading Level 2 {section number}.{subsection number}.{clause number} Body text under Heading Level 2 should expand to: 2 Heading 1 2.1 Heading 2 2.1.1 Body text under Heading Level 2 2.1.2 Body text under Heading Level 2 2.1.3 Body text under Heading Level 2 The numbered body text paragraphs shouldn't show up the Table of Contents. I couldn't find the right way to do that, whether in multilevel lists, fields, styles, etc. How do I do it right?

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  • Scipy Negative Distance? What?

    - by disappearedng
    I have a input file which are all floating point numbers to 4 decimal place. i.e. 13359 0.0000 0.0000 0.0001 0.0001 0.0002` 0.0003 0.0007 ... (the first is the id). My class uses the loadVectorsFromFile method which multiplies it by 10000 and then int() these numbers. On top of that, I also loop through each vector to ensure that there are no negative values inside. However, when I perform _hclustering, I am continually seeing the error, "Linkage Z contains negative values". I seriously think this is a bug because: I checked my values, the values are no where small enough or big enough to approach the limits of the floating point numbers and the formula that I used to derive the values in the file uses absolute value (my input is DEFINITELY right). Can someone enligten me as to why I am seeing this weird error? What is going on that is causing this negative distance error? ===== def loadVectorsFromFile(self, limit, loc, assertAllPositive=True, inflate=True): """Inflate to prevent "negative" distance, we use 4 decimal points, so *10000 """ vectors = {} self.winfo("Each vector is set to have %d limit in length" % limit) with open( loc ) as inf: for line in filter(None, inf.read().split('\n')): l = line.split('\t') if limit: scores = map(float, l[1:limit+1]) else: scores = map(float, l[1:]) if inflate: vectors[ l[0]] = map( lambda x: int(x*10000), scores) #int might save space else: vectors[ l[0]] = scores if assertAllPositive: #Assert that it has no negative value for dirID, l in vectors.iteritems(): if reduce(operator.or_, map( lambda x: x < 0, l)): self.werror( "Vector %s has negative values!" % dirID) return vectors def main( self, inputDir, outputDir, limit=0, inFname="data.vectors.all", mappingFname='all.id.features.group.intermediate'): """ Loads vector from a file and start clustering INPUT vectors is { featureID: tfidfVector (list), } """ IDFeatureDic = loadIdFeatureGroupDicFromIntermediate( pjoin(self.configDir, mappingFname)) if not os.path.exists(outputDir): os.makedirs(outputDir) vectors = self.loadVectorsFromFile( limit, pjoin( inputDir, inFname)) for threshold in map( lambda x:float(x)/30, range(20,30)): clusters = self._hclustering(threshold, vectors) if clusters: outputLoc = pjoin(outputDir, "threshold.%s.result" % str(threshold)) with open(outputLoc, 'w') as outf: for clusterNo, cluster in clusters.iteritems(): outf.write('%s\n' % str(clusterNo)) for featureID in cluster: feature, group = IDFeatureDic[featureID] outline = "%s\t%s\n" % (feature, group) outf.write(outline.encode('utf-8')) outf.write("\n") else: continue def _hclustering(self, threshold, vectors): """function which you should call to vary the threshold vectors: { featureID: [ tfidf scores, tfidf score, .. ] """ clusters = defaultdict(list) if len(vectors) > 1: try: results = hierarchy.fclusterdata( vectors.values(), threshold, metric='cosine') except ValueError, e: self.werror("_hclustering: %s" % str(e)) return False for i, featureID in enumerate( vectors.keys()):

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  • Between-request Garbage Collection using Passenger

    - by raphaelcm
    We're using Rails 3.0.7 and REE 1.8.7. Long-term, we will be upgrading, but at the moment it's not feasible. Following the advice of several blog posts, we've been tuning our GC, and have settings that work pretty well. But we would really like to run GC outside of the request-response cycle. I've tried patching Passenger per this post, and using the code supplied in this SO question. In both cases, GC does indeed happen between requests. However, every time the between-request GC happens, I see a bunch of this: MONGODB [INFO] Connecting... MONGODB admin['$cmd'].find({:ismaster=>1}).limit(-1) MONGODB admin['$cmd'].find({:ismaster=>1}).limit(-1) MONGODB admin['$cmd'].find({:ismaster=>1}).limit(-1) Starting the New Relic Agent. Installed New Relic Browser Monitoring middleware SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES RefinerySetting Load (0.0ms) SELECT `refinery_settings`.* FROM `refinery_settings` WHERE `refinery_settings`.`scoping` = 'pages' AND `refinery_settings`.`name` = 'use_marketable_urls' LIMIT 1 SQL (0.0ms) BEGIN RefinerySetting Load (0.0ms) SELECT `refinery_settings`.* FROM `refinery_settings` WHERE `refinery_settings`.`id` = 1 LIMIT 1 AREL (0.0ms) UPDATE `refinery_settings` SET `value` = '--- \"false\"\n', `callback_proc_as_string` = NULL WHERE `refinery_settings`.`id` = 1 SQL (0.0ms) SHOW TABLES RefinerySetting Load (0.0ms) SELECT `refinery_settings`.* FROM `refinery_settings` SQL (0.0ms) COMMIT SQL (0.0ms) SHOW TABLES RefinerySetting Load (4.0ms) SELECT `refinery_settings`.* FROM `refinery_settings` WHERE `refinery_settings`.`scoping` IS NULL AND `refinery_settings`.`name` = 'user_image_sizes' LIMIT 1 SQL (0.0ms) BEGIN RefinerySetting Load (0.0ms) SELECT `refinery_settings`.* FROM `refinery_settings` WHERE `refinery_settings`.`id` = 17 LIMIT 1 AREL (0.0ms) UPDATE `refinery_settings` SET `value` = '--- \n:small: 120x120>\n:medium: 280x280>\n:large: 580x580>\n', `callback_proc_as_string` = NULL WHERE `refinery_settings`.`id` = 17 SQL (0.0ms) SHOW TABLES RefinerySetting Load (0.0ms) SELECT `refinery_settings`.* FROM `refinery_settings` SQL (0.0ms) COMMIT ******** Engine Extend: app/helpers/blog_posts_helper SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES SQL (4.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES ******** Engine Extend: app/models/user SQL (0.0ms) describe `roles_users` SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES SQL (4.0ms) describe `roles_users` SQL (0.0ms) SHOW TABLES SQL (4.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES SQL (0.0ms) SHOW TABLES (etc, etc, etc) Which is what happens when rails "loads the world" when the app starts up. Basically, GC.start is re-loading the app for some reason. Because of this, between-request GC is much slower than inline GC. Is there a way around this? I would love to have snappy, between-request GC if possible. Thanks.

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  • Passing the CAML thru the EY of the NEEDL

    - by PointsToShare
    © 2011 By: Dov Trietsch. All rights reserved Passing the CAML thru the EY of the NEEDL Definitions: CAML (Collaborative Application Markup Language) is an XML based markup language used in Microsoft SharePoint technologies  Anonymous: A camel is a horse designed by committee  Dov Trietsch: A CAML is a HORS designed by Microsoft  I was advised against putting any Camel and Sphinx rhymes in here. Look it up in Google!  _____ Now that we have dispensed with the dromedary jokes (BTW, I have many more, but they are not fit to print!), here is an interesting problem and its solution.  We have built a list where the title must be kept unique so I needed to verify the existence (or absence) of a list item with a particular title. Two methods came to mind:  1: Span the list until the title is found (result = found) or until the list ends (result = not found). This is an algorithm of complexity O(N) and for long lists it is a performance sucker. 2: Use a CAML query instead. Here, for short list we’ll encounter some overhead, but because the query results in an SQL query on the content database, it is of complexity O(LogN), which is significantly better and scales perfectly. Obviously I decided to go with the latter and this is where the CAML s--t hit the fan.   A CAML query returns a SPListItemCollection and I simply checked its Count. If it was 0, the item did not already exist and it was safe to add a new item with the given title. Otherwise I cancelled the operation and warned the user. The trouble was that I always got a positive. Most of the time a false positive. The count was greater than 0 regardles of the title I checked (except when the list was empty, which happens only once). This was very disturbing indeed. To solve my immediate problem which was speedy delivery, I reverted to the “Span the list” approach, but the problem bugged me, so I wrote a little console app by which I tested and tweaked and tested, time and again, until I found the solution. Yes, one can pass the proverbial CAML thru the ey of the needle (e’s missing on purpose).  So here are my conclusions:  CAML that does not work:  Note: QT is my quote:  char QT = Convert.ToChar((int)34); string titleQuery = "<Query>><Where><Eq>"; titleQuery += "<FieldRef Name=" + QT + "Title" + QT + "/>"; titleQuery += "<Value Type=" + QT + "Text" + QT + ">" + uniqueID + "</Value></Eq></Where></Query>"; titleQuery += "<ViewFields><FieldRef Name=" + QT + "Title" + QT + "/></ViewFields>";  Why? Even though U2U generates it, the <Query> and </Query> tags do not belong in the query that you pass. Start your query with the <Where> clause.  Also the <ViewFiels> clause does not belong. I used this clause to limit the returned collection to a single column, and I still wish to do it. I’ll show how this is done a bit later.   When you use the <Query> </Query> tags in you query, it’s as if you did not specify the query at all. What you get is the all inclusive default query for the list. It returns evey column and every item. It is expensive for both server and network because it does all the extra processing and eats plenty of bandwidth.   Now, here is the CAML that works  string titleQuery = "<Where><Eq>"; titleQuery += "<FieldRef Name=" + QT + "Title" + QT + "/>"; titleQuery += "<Value Type=" + QT + "Text" + QT + ">" + uniqueID + "</Value></Eq></Where>";  You’ll also notice that inside the unusable <ViewFields> clause above, we have a <FieldRef> clause. This is what we pass to the SPQuery object. Here is how:  SPQuery query = new SPQuery(); query.Query = titleQuery; query.ViewFields = "<FieldRef Name=" + QT + "Title" + QT + "/>"; query.RowLimit = 1; SPListItemCollection col = masterList.GetItems(query);  Two thing to note: we enter the view fields into the SPQuery object and we also limited the number of rows that the query returns. The latter is not always done, but in an existence test, there is no point in returning hundreds of rows. The query will now return one item or none, which is all we need in order to verify the existence (or non-existence) of items. Limiting the number of columns and the number of rows is a great performance enhancer. That’s all folks!!

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  • MERGE gives better OUTPUT options

    - by Rob Farley
    MERGE is very cool. There are a ton of useful things about it – mostly around the fact that you can implement a ton of change against a table all at once. This is great for data warehousing, handling changes made to relational databases by applications, all kinds of things. One of the more subtle things about MERGE is the power of the OUTPUT clause. Useful for logging.   If you’re not familiar with the OUTPUT clause, you really should be – it basically makes your DML (INSERT/DELETE/UPDATE/MERGE) statement return data back to you. This is a great way of returning identity values from INSERT commands (so much better than SCOPE_IDENTITY() or the older (and worse) @@IDENTITY, because you can get lots of rows back). You can even use it to grab default values that are set using non-deterministic functions like NEWID() – things you couldn’t normally get back without running another query (or with a trigger, I guess, but that’s not pretty). That inserted table I referenced – that’s part of the ‘behind-the-scenes’ work that goes on with all DML changes. When you insert data, this internal table called inserted gets populated with rows, and then used to inflict the appropriate inserts on the various structures that store data (HoBTs – the Heaps or B-Trees used to store data as tables and indexes). When deleting, the deleted table gets populated. Updates get a matching row in both tables (although this doesn’t mean that an update is a delete followed by an inserted, it’s just the way it’s handled with these tables). These tables can be referenced by the OUTPUT clause, which can show you the before and after for any DML statement. Useful stuff. MERGE is slightly different though. With MERGE, you get a mix of entries. Your MERGE statement might be doing some INSERTs, some UPDATEs and some DELETEs. One of the most common examples of MERGE is to perform an UPSERT command, where data is updated if it already exists, or inserted if it’s new. And in a single operation too. Here, you can see the usefulness of the deleted and inserted tables, which clearly reflect the type of operation (but then again, MERGE lets you use an extra column called $action to show this). (Don’t worry about the fact that I turned on IDENTITY_INSERT, that’s just so that I could insert the values) One of the things I love about MERGE is that it feels almost cursor-like – the UPDATE bit feels like “WHERE CURRENT OF …”, and the INSERT bit feels like a single-row insert. And it is – but into the inserted and deleted tables. The operations to maintain the HoBTs are still done using the whole set of changes, which is very cool. And $action – very convenient. But as cool as $action is, that’s not the point of my post. If it were, I hope you’d all be disappointed, as you can’t really go near the MERGE statement without learning about it. The subtle thing that I love about MERGE with OUTPUT is that you can hook into more than just inserted and deleted. Did you notice in my earlier query that my source table had a ‘src’ field, that wasn’t used in the insert? Normally, this would be somewhat pointless to include in my source query. But with MERGE, I can put that in the OUTPUT clause. This is useful stuff, particularly when you’re needing to audit the changes. Suppose your query involved consolidating data from a number of sources, but you didn’t need to insert that into the actual table, just into a table for audit. This is now very doable, either using the INTO clause of OUTPUT, or surrounding the whole MERGE statement in brackets (parentheses if you’re American) and using a regular INSERT statement. This is also doable if you’re using MERGE to just do INSERTs. In case you hadn’t realised, you can use MERGE in place of an INSERT statement. It’s just like the UPSERT-style statement we’ve just seen, except that we want nothing to match. That’s easy to do, we just use ON 1=2. This is obviously more convoluted than a straight INSERT. And it’s slightly more effort for the database engine too. But, if you want the extra audit capabilities, the ability to hook into the other source columns is definitely useful. Oh, and before people ask if you can also hook into the target table’s columns... Yes, of course. That’s what deleted and inserted give you.

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  • Why are my uWSGI processes dying immediately?

    - by orokusaki
    I'm using Supervisor and the uWSGI Emperor mode. When I set limit-as to 512 (MB), workers die instantly (respawn, die, respawn, die, every 3/4 of a second or so): [uwsgi] workers = 4 threads = 40 limit-as = 512 harakiri = 20 max-requests = 1600 ... non-performance/memory/processor-related settings ommitted But, if I change limit-as to: [uwsgi] workers = 4 threads = 40 limit-as = 1024 harakiri = 20 max-requests = 1600 ... non-performance/memory/processor-related settings ommitted and restart uwsgi, the problem is gone immediately. In order to put a sham in this, I've modified the setting back to 512, restarted again, and the problem is back immediately. Notes: My app is a simple Django app without much additional Python setup during start-up time.

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