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3
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0answers
87 views

Sort operation SQL Server 2012

I am trying to optimize a query and the sort operation (91% cost) is the costliest operation. Any help will be appreciated. Query is : SELECT TOP 1 ArchiveType, CONVERT(NVARCHAR(30), ...
2
votes
0answers
114 views

Schema for user drag and drop ordering

I'm trying to work out the schema for a system where users will be able to order items in an (unlimited length) list by drag and drop. Is there any kind of standard way of storing this ordering ...
1
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0answers
4 views

How does the use of derived tables speed up sorting?

In the article 45 Ways To Speed Up Firebird Database, it states that Use derived tables to optimize SELECT with ORDER BY/GROUP BY Another way to optimize SQL query with sorting is to ...
1
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0answers
69 views

HQL pagination returns same result on different pages - with SQL

We have the following query in the server (using sql): Query query = this.entityManager.createQuery( "SELECT type, id, date, amount FROM Transaction ORDER BY type ASC"); The type field ...
1
vote
0answers
17 views

Access algorithms in Partial Index implementation of PostgreSQL 9.4?

I am studying big-O time-space complexities of different algorithms with the partial index of PostgreSQL 9.4: introsort (O(n log n)-time, O(log n)-space) and heapsort (O(n log(n))-time ...
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0answers
23 views

Custom cycling order in MySQL

Having following Foo table: id | name | group ===|=========|====== 1 | "John" | 1 2 | "Paul" | 1 3 | "Marry" | 1 4 | "Josh" | 1 5 | "Mike" | 2 6 | "Kevin" | 2 7 | "Ramon" | 2 8 | "Kim" ...
1
vote
0answers
103 views

Can't get rid of filesort on joined query sorting on second table

For some reason, this query: EXPLAIN SELECT * FROM biz as b INNER JOIN listings as l ON b.id = l.biz_id WHERE l.pub_id = 14 AND b.cat_id=310 ORDER BY l.level DESC, l.random DESC LIMIT 5; says it ...
0
votes
0answers
32 views

How to add an index to attributes sorted on in mongodb

Before you find another reason for changing the category of this question, it was on Stack Overflow and it was described as a DB Admin question, so here goes: I am running a reporting app with ...
0
votes
0answers
52 views

Speed up sorting in this query

I'm trying to optimize the following plan and noticed that PostgreSQL spends a lot of time (relatively speaking) on sorting before the merge joins. Is there a way (using indexes, cluster the table, ...
0
votes
0answers
2k views

MySQL: High sort_buffer_size setting value

Thing is I was getting plenty of 131104 20:10:36 [ERROR] /usr/sbin/mysqld: Sort aborted with 256M and rather erratic behaviour in my load test. Now at sort_buffer_size = 1024M ...
0
votes
0answers
63 views

Faster way to GROUP or ORDER dynamic fields?

We have this query in our app, that searches a table for a song title using MATCH AGAINST and picks the most relevant results. The table has around a million results and is growing. The app has been ...