Memoize results from the fast predicate matcher

This gains another 15% for the parser, again with a very simple change
that has no impact if the fast predicate matcher fails to work.

2 files changed, 18 insertions, 1 deletions

diff --git a/src/xact.cc b/src/xact.cc
index 330ad38a..a84b4dca 100644
--- a/src/xact.cc
+++ b/src/xact.cc
@@ -597,10 +597,25 @@ void auto_xact_t::extend_xact(xact_base_t& xact)
     bool matches_predicate = false;
     if (try_quick_match) {
       try {
+	bool found_memoized_result = false;
+	if (! memoized_results.empty()) {
+	  std::map<string, bool>::iterator i =
+	    memoized_results.find(initial_post->account->fullname());
+	  if (i != memoized_results.end()) {
+	    found_memoized_result = true;
+	    matches_predicate = (*i).second;
+	  }
+	}
+
 	// Since the majority of people who use automated transactions simply
 	// match against account names, try using a *much* faster version of
 	// the predicate evaluator.
-	matches_predicate = post_pred(predicate.get_op(), *initial_post);
+	if (! found_memoized_result) {
+	  matches_predicate = post_pred(predicate.get_op(), *initial_post);
+	  memoized_results.insert
+	    (std::pair<string, bool>(initial_post->account->fullname(),
+				     matches_predicate));
+	}
       }
       catch (...) {
 	DEBUG("xact.extend.fail",
diff --git a/src/xact.h b/src/xact.h
index 07f9a6c7..c819b2a0 100644
--- a/src/xact.h
+++ b/src/xact.h
@@ -148,6 +148,8 @@ public:
   predicate_t predicate;
   bool        try_quick_match;
 
+  std::map<string, bool> memoized_results;
+
   auto_xact_t() : try_quick_match(true) {
     TRACE_CTOR(auto_xact_t, "");
   }