search : Extend "intial burst" optimization to return all results by chunks

This way, the user gets a steady (but bursty) stream of reults. We
double the chunk size each time since each successive chunk has to
redo work from all previous chunks.

Of course, the overall time is thereby slower, as the price we pay for
increased responsiveness. With a search returning about 17000 thread
results I measured a total time of 48.8 seconds before this change and
58.4 seconds afterwards.

1 files changed, 5 insertions, 0 deletions

diff --git a/TODO b/TODO
index 65d6c75..da8f7c9 100644
--- a/TODO
+++ b/TODO
@@ -134,6 +134,11 @@ Add support for configuring "virtual tags" which are a tuple of
 (tag-name, search-specification). The database is responsible for
 ensuring that the virtual tag is always consistent.
 
+Think about optimizing chunked searches (max-threads > 0) to avoid
+repeating work. That would be saving state from the previous chunk and
+reusing it if the next search is the next chunk with the same search
+string.
+
 General
 -------
 Audit everything for dealing with out-of-memory (and drop xutil.c).