Proximity doesn't work for larger results.

• Article Type: General
• Product: Aleph
• Product Version: 18.01

Description:
Proximity searching doesn't work for larger result sets. For instance: when you search for "plants !3 periodicals", you get the same 174 records you do if you search for "plants and periodicals". In some of the records, the words are more than 3 words apart. Why?

Resolution:
This is due to the set_prox_limit variable, specified in www_server.conf:.
setenv set_prox_limit 100.
(which is how it has been distributed in v15, v16, and v17)..
After increasing this to 999999, proximity worked fine..
set_prox_limit was added to keep big proximity searches from monopolizing system resources. Prior to the introduction of the word-pair adjacency -- when adjacency was done using zero-level proximity --, such concern might have been warranted. But now that we are using the word-pairs for adjacency, the only use of proximity is these explicit "!" or "%" searches -- which are certainly going to be relatively few, and I do not think that we need to worry about them..
The program takes the results from the AND-ing of the terms, compares that number to set_prox_limit, and, if less, does proximity-processing..
We suggest that all sites using the proximity fucntion change their set_prox_limit to the maximum, 999999. If you find through experience that proximity searches with AND-ed results greater than n always time out, you may want to set it to n..
From v18 the limit is increased (set_prox_limit to 500).

• Article last edited: 10/8/2013