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| bio | website | |
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| visits | member for | 7 months |
| seen | Jun 1 at 13:44 | |
| stats | profile views | 11 |
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Mar 10 |
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db INDEX on ORDER BY FIELD in very simple query does not help - still slow response? I dont know anything about db2, but assuming it is similar to SQL Server, did you try a clustered index instead of a non clustered index (since you are using a select * query)? |
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Jan 15 |
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Fetch Records alternatively from database hmm.. apparently theres no straightforward way to do it in MySQL since it doesn't have the equivalents of a CTE or RowNumber, so any method I suggest would be hacky. Probably try out Neo's answer if it works for you (and take ahofmann's advise for the future) |
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Jan 15 |
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Fetch Records alternatively from database Don't know if its possible in MySQL, but how about using a ROWNUMBER() over Date_Time , join the CTE with itself, with the join condition as rownumber+1 and a where condition to filter out records where the left rownumber is even or the right rownumber is odd |
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Jan 15 |
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Stateful views in SQL Server @despicable updated answer with more info |
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Jan 14 |
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How does paging work with ROW_NUMBER in SQL Server? Ah, you're right, theres a performance difference. I had read this: blogs.technet.com/b/dataplatforminsider/archive/2011/11/01/… where he mentions no difference, but just saw channel9.msdn.com/posts/SQL11UPD03-REC-02 where he shows theres a lot of difference.. (though in the audio underemphasis the performance difference) |
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Jan 14 |
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How does paging work with ROW_NUMBER in SQL Server? Should be noted though that OFFSET/FETCH NEXT do not offer any performance benefits over the CTE method |
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Dec 12 |
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Forcing an index spool Updated the statistics, though I have the actual data in the table. Still getting the row count spool, guess its a build difference since I'm on 11.0.2218 |
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Dec 12 |
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Forcing an index spool Tried the 1st method, and it works. Thanks. But I get a row count spool after the index spool which you do not get in the plan you have shown. Any idea why? |
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Dec 11 |
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Why are there execution plan differences between OFFSET … FETCH and the old-style ROW_NUMBER scheme? Not very sure, so putting it as comment, but I guess its because you have the same order by condition for the row numbering and the final result set. Since in the 2nd condition, the optimizer knows this, it does not need to sort the results again. In the first case however, it need to make sure the results from the outer select are sorted as well as the row numbering in the inner result. Creating a proper index on #objects should solve the issue |
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Nov 29 |
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DBCC TRACEON (652) does not disable read ahead reads Wow, found out 2 awesome things in a single answer, though wondering, how did you find out that there is an exceptional case with the Batch Hash table build? Did you read about that somewhere, or was it just from trial and error? |
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Nov 28 |
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Will using bigint vs mediumint have a performance impact? Kind of OT, but you mention Why does the user know the value of the ID column? . Isnt this acceptable behaviour in some cases? Example: students in a school will know their roll numbers, and that will probably be the only value uniquely identifying them. The same can be said for a bank account number as well. |
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Nov 27 |
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DBCC TRACEON (652) does not disable read ahead reads @MartinSmith No, I do have Hash Match (Inner Join) and parallelism though. Have uploaded the XML execution plan, though I have no clue how to read it |
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Nov 26 |
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Bitwise operations in TSQL True, but like in C I can say 0x00000010 to represent 16 in hexadecimal, or 0b00000010 to represent 2 in binary, is there a similar set of notations for TSQL? |
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Nov 26 |
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Bitwise operations in TSQL Ohk.. I'm actually moving to a SQL role from a C background, and atleast there, bitwise operators are usually noticeably faster than integer operators. I thought it would translate here as well |
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Nov 26 |
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Bitwise operations in TSQL oh.. Got it. Is there a way to specify binary numbers in T-SQL? |
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Nov 26 |
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Bitwise operations in TSQL But I explicitly casted 100 to binary |
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Nov 12 |
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How much work actually happens on SSMS and how much on the server itself? So,just so I understand correctly, in a query such as the one I mentioned in the question, the loop is also running on the server, and 2 million insert calls are not being made over the network? |
