tree 01fb72b40ddd2e56eef503dbc271b21aa9b36d95
parent ade5327ad6efe3d70486f828ecac9f234d8c8020
author ulfjack <ulfjack@google.com> 1561991779 -0700
committer Copybara-Service <copybara-worker@google.com> 1561991929 -0700

Query performance: don't copy on every eval call

Every query function calls into this method to eval any relevant
sub-queries, and making a copy on every call is a very, very expensive
proposition. However, graphless query does not use streaming, i.e., all
functions make a single call to the callback, so this defensive
mechanism is simply unnecessary.

We only make this change for the new query environment, rather than more
generally.

For queries with a hot Bazel server (and all packages already loaded),
this can improve performance by as much as 2x.

Before (first run omitted):
real    0m1.308s
real    0m1.285s
real    0m1.524s

After (first run omitted):
real    0m0.650s
real    0m0.549s
real    0m0.521s

PiperOrigin-RevId: 255951627