From f82e693a31d07ab8b391888ff60eb7ff5b95bd13 Mon Sep 17 00:00:00 2001
From: Siying Dong <siying.d@fb.com>
Date: Thu, 16 May 2019 15:20:19 -0700
Subject: [PATCH] RangeDelAggregator::StripeRep::Invalidate() to be skipped if
 empty (#5312)

Summary:
RangeDelAggregator::StripeRep::Invalidate() clears up several vectors. If we know there isn't anything to there, we can safe these small CPUs. Profiling shows that it sometimes take non-negligible amount of CPU. Worth a small optimization.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5312

Differential Revision: D15380511

Pulled By: siying

fbshipit-source-id: 53c5f34c33b4cb1e743643c6086ac56d0b84ec2e
---
 db/range_del_aggregator.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/db/range_del_aggregator.h b/db/range_del_aggregator.h
index e593807d5..ce7897a97 100644
--- a/db/range_del_aggregator.h
+++ b/db/range_del_aggregator.h
@@ -320,8 +320,10 @@ class RangeDelAggregator {
                       RangeDelPositioningMode mode);
 
     void Invalidate() {
-      InvalidateForwardIter();
-      InvalidateReverseIter();
+      if (!IsEmpty()) {
+        InvalidateForwardIter();
+        InvalidateReverseIter();
+      }
     }
 
     bool IsRangeOverlapped(const Slice& start, const Slice& end);