On 3/7/07, mark angelillo <

[hidden email]> wrote:

> Hello,

>

> I've got a Solr index running and I want to use a dynamicField to

> store n different sorting fields. The field that is used to actually

> sort the results will be determined by the application that is

> querying the index.

>

> I'm wondering if anyone has done something similar to this, or if

> anyone has an idea of how Solr will perform as the number n of

> sorting fields grows larger. Is there a way to make sure this doesn't

> start to slow the index down? Is there any information out there

> about the number of dynamicFields that can be declared in this way

> before the entire index suffers? Is there such a limit?

It's not realy about the number of dynamic fields. The key variable

is the number of sort fields. To sort efficiently, solr needs to

maintain a cache of field values. This consumes memory per-field on

the order of

D x S + U

where D is the document count, S is the the size of the data type (eg.

4bytes for ints, 8 bytes for doubles, 4/8 bytes for anything else

[pointers]), and U is the cumulative size of the unique field values

(if sorting on a non-primitive type, like Strings).

If you have sufficient memory to store this data for each field you

are sorting on, you shouldn't have any problems.

best,

-Mike