Hidden inefficiencies in Interchange searching
August 13, 2012
A very common, somewhat primitive approach to Interchange searching uses an approach like this:
The search profile contains something along the lines of
mv_search_type=db mv_search_file=products mv_column_op=rm mv_numeric=0 mv_search_field=category [search-region] [item-list] [item-field description] [/item-list] [/search-region]
In other words, we search the products table for rows whose column “category” matches an expression (with a single query), and we list all the matches (description only). However, this can be inefficient depending on your database implementation: the item-field tag issues a query every time it’s encountered, which you can see if you “tail” your database log. If your item-list contains many different columns from the search result, you’ll end up issuing many such queries:
[item-list] [item-field description], [item-field weight], [item-field color], [item-field size], [item field ...] ...
SELECT description FROM products WHERE sku='ABC123' SELECT weight FROM products WHERE sku='ABC123' SELECT color FROM products WHERE sku='ABC123' SELECT size FROM products WHERE sku='ABC123' ...
(Now, some databases are smart enough to cache query results, but some aren’t, so avoiding this extra work is probably worth your trouble even on a “smart” database, in case your Interchange application gets moved to a “dumb” database sometime in the future.)
Fortunately, it’s easy to correct:
... [item-param description] ...
in place of “item-field”.