While profiling some code making heavy use of Adam Kennedy's ORLite module for accessing a SQLite database I found that most of my time was spend in DBI.pm.
Sorted by inclusive time (ie. including time spent in subroutines) two non-XS functions stood out: selectall_arrayref and fetchall_arrayref. Looking a the code both of these functions had a comment stating that a C implementation existed in Drivers.xst and the comment at selectall_arrayref further said that the Perl version is used as a fallback if a slice is given
So could I get away with the slicing?
Turned out to quite easy. Just use array refs as objects instead of the usual hash refs.
The run time of the select() method provided by ORLite went from 344µs/call to 162µs/call on average. And as my test data makes at roughly 100000 select() calls this is a quite noticeable speedup. All included my running time (under Devel::NYTProf) improved from 400 seconds to 340 seconds.
Unfortunately I have to be able to update the state of my ORLite generated objects. This was easy while the objects was blessed has refs. Array refs are not as easy to update. The easy solution was to make the simple non-fk accessors to be lvalue subroutines.