The Asana search engine is useful but has some limitations relative to other software languages and applications.
The most notable is the lack of regular expressions as an search option. Booleans, grouping, quantification and wildcards are powerful features that required to search large amounts of data efficiently and effectively. Pattern matching in its current implementation is unsophisticated. This is a major limitation in Asana Search.
The second limitation is the limited set of search filters. The search engine assumes that you want to search all database object types (projects, tasks, etc.) when you may are just interested in a single type or subset of types. The current filters are usable but understanding the advanced features is somewhat daunting for the casual user.