Randomize search result in sphinx

Hi im using sphinx 201 beta (r2792)

i have rt index with rt_attr_uint = rake my goal is to sort results by this attribute whitch work as expected us开发者_如何学Going

$this->sphinx->SetSortMode(SPH_SORT_EXTENDED, 'rake DESC')

but i want to also randomize this result ... lets say i have this data

(id,  title,  rake)
  1, 'test',  3
  2, 'test2', 3
  3, 'ásdf',  1
  4, 'rreer', 0

so after i append random

$this->sphinx->SetSortMode(SPH_SORT_EXTENDED, 'rake DESC, @random')

i would expect randomize result sorted by attribute rake descending but im getting error:

sort-by attribute '@random' not found

whitch i dont understand because this random attribute is internal attribute am i doing something wrong? where could be a problem? thanks

---

What I did is create the random number on the SQL query

SELECT ...  RAND() as random_sort, ...

Added it as an attribute

sql_attr_float = random_sort

And then use it in the extended sort query

$this->sphinx->SetSortMode(SPH_SORT_EXTENDED, 'rake DESC, random_sort DESC');

---

From my quick tests, it looks like Sphinx only supports @random if it is the only attribute in the sort clause. So I'm afraid you're out of luck - either you just sort randomly, or you just sort by rake.

---

For real time randomness, index the ids and sort using expr mode with an expression like this (not sure this one is 100% random):

( ( ( id % #{pagesize} + #{rand(pagesize * 2)} ) % #{pagesize} ) / #{pagesize} )

Add an If statement to the expression above to use your rake attribute.

[http://sphinxsearch.com/docs/1.10/sorting-modes.html][1]