Talk:How to implement a custom XUL query processor component

From MDC

Javascript Performance

Unfortunately, Query Processors implemented in Javascript have performance problems for large result sets. Although they are useful for prototyping new datasources and for small data sets, any application requiring templates which create large numbers of results should not rely on JS Query Processors.

Although the exact details are unclear, the performance problem appears to be caused by crossing the C++-->Javascript boundary. At this time, I suspect the result tree is being copied repeatedly, resulting in N^2 performance. Pvh