For example, searching on a character field with 'abc%' is not an

table in the AdventureWorks2016 database. However, one of my clients hit a neat edge case scenario where SELECT * queries actually ran faster than picking a subset of columns. But by doing a simple test, it is easy to find it. I’ve not had a chance yet to really dig into Query Store and its capabilities, but from what I can see in the MS docs about Query Store’s DMV’s, I’d be able to dig into sys.query_store_plan to find plans with this sort of issue, right? As a result, the 2 nd and 3 rd queries are slower than the 1 st query. The script below populates the table using the data from the [Person]. EDIT: Disagree on the duplicate flag. Note that I'm gathering statistics in full at the end. store the reverse order of the string, but if you are designing the database system, So other than dumping this view into an actual table (quite sloppy) - I can't get around their "top 500" addendum either. Scan and instead of an Index Seek.
Basically, we have converted our query to make it Sargable as 'abc%'. Also, my understanding is that Top 100 is a different algorithm than Top 100+. Database Performance Analyzer can be integrated with other SolarWinds products through the Orion ® Platform . Features of the data engine’s automatic partitioning … We could use an alternative method to get the same result more efficiently with
(String%) it uses the index, but if I put it the front (%String) it does a scan Privacy Policy – Terms and Conditions, {"cart_token":"","hash":"","cart_data":""}, sp_BlitzFirst – instant performance check, sp_BlitzQueryStore – analyze queries over time. Swapping out our Syntax Highlighter. an Index Scan, meaning the entire index of cust_name had to be scanned to find just This is SQL Server 2012. The query optimizer will attempt to use the fact that it doesn't need to return all rows to create a more efficient query plan. It only takes a minute to sign up. rows where the name starts with 'Aaron'. Hi Brent, a little bit of a tangent, but…. The row goal can cause the cost of some operators to be scaled down. with '%abc'. It's great! It would be better, to create a computed column for the reverse column (cust_name_reverse AS REVERSE(cust_name)). We will need that column later. You can also subscribe without commenting. Note that the INSERT query uses the REVERSE function to generate the customer Supposing I want to find %string% , is it still faster to perform two Selects ( one for string% and another string% for 'reversed' column)? I do not think, it will faster than the single SELECT.

Use automatic partitioning SQL server features. Which is, the TOP X query will SORT potentially massive tables very early on, not AFTER they are aggregated/ filtered/ etc. Since the cust_name_reverse will usually not be selected, there is no need to add the PERSISTED keyword to the column definition.This way you don't have to worry about inconsitent data, because someone run somewhere an update without manually adjusting the cust_name_reverse and / or do not need triggers to prevent this.

How can I make this search (%String) more efficient? However, the 2nd and 3rd

In this case, you would write a query as Let's execute both queries at once and compare the execution plans and cost comparison. I still don’t fully understand getters & setters. This would be the EXPECTED behavior, returning less rows. I can't say anything about your query in particular without seeing the query plans, but hopefully this example illustrates the general point. I’d say that’s true in 99.99% of cases out in the real world, too: you only want to select the specific columns you need. Having the wildcard (%) at the end of the string when searching on uncertain Using MERGE in SQL Server to insert, update and delete at the same time, Rolling up multiple rows into a single row and column for SQL Server data, SQL Server Loop through Table Rows without Cursor, Split Delimited String into Columns in SQL Server with PARSENAME. The why is a mystery, but the how is plainly there. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. In this query’s case, the spill doesn’t really matter – the SELECT Id is still faster. I can’t share the exact query, but I can share a query that can at least illustrate the underlying concept. Where is your line with students on social media. Obviously, I'm going to look at the execution plans here ---- but once I figure out why SQL Server is running the "top 500" in suboptimal fashion, how do I actually tell it to run the plan the quick way, like taking the full table? Too much, in fact, but who’s counting? The first query is faster because the WHERE condition is Sargable. of the index. Starting at around the nine minute mark, I run this query: The Stack Overflow database doesn’t ship with an index on Reputation by default, so SQL Server needs to sort all of the users by reputation in order to find the top 250. columns. As a result, the 2nd That hint disables the row goal optimization at the query level. EDIT: Disagree on the duplicate flag. Some names and products listed are the registered trademarks of their respective owners.