From f8b5ef85ec159d1b8e5db2c8a3f57dd3aa5771be Mon Sep 17 00:00:00 2001
From: sdong <siying.d@fb.com>
Date: Thu, 16 Jan 2020 10:46:05 -0800
Subject: [PATCH] Fix a bug caused by recent fix of Prefix Hash (#6302)

Summary:
Recent fix to Prefix Hash https://github.com/facebook/rocksdb/pull/6292 caused a bug that the newly created NotFound status in hash index is never reset. This causes reseek or implict reseek to return wrong results sometimes.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6302

Test Plan:
Add a unit test that would fail. Not fix.
crash test with hash test would fail in several seconds. With the fix, it will run about several minutes before failing with another failure.

Differential Revision: D19424572

fbshipit-source-id: c5276f36a95fd0e2837e30190476d2fe21ed8566
---
 db/db_test2.cc             | 4 ++++
 table/block_based/block.cc | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/db/db_test2.cc b/db/db_test2.cc
index 7f724ac72..e74344410 100644
--- a/db/db_test2.cc
+++ b/db/db_test2.cc
@@ -4355,6 +4355,10 @@ TEST_F(DBTest2, BlockBasedTablePrefixIndexSeekForPrev) {
     if (iterator->Valid()) {
       ASSERT_EQ("a1", iterator->key().ToString());
     }
+
+    iterator->SeekForPrev("y3");
+    ASSERT_TRUE(iterator->Valid());
+    ASSERT_EQ("y1", iterator->key().ToString());
   }
 }
 
diff --git a/table/block_based/block.cc b/table/block_based/block.cc
index cfa042d6e..1aa5bfe54 100644
--- a/table/block_based/block.cc
+++ b/table/block_based/block.cc
@@ -390,6 +390,7 @@ void IndexBlockIter::Seek(const Slice& target) {
   if (data_ == nullptr) {  // Not init yet
     return;
   }
+  status_ = Status::OK();
   uint32_t index = 0;
   bool ok = false;
   if (prefix_index_) {
@@ -470,6 +471,7 @@ void IndexBlockIter::SeekToFirst() {
   if (data_ == nullptr) {  // Not init yet
     return;
   }
+  status_ = Status::OK();
   SeekToRestartPoint(0);
   ParseNextIndexKey();
 }
@@ -488,6 +490,7 @@ void IndexBlockIter::SeekToLast() {
   if (data_ == nullptr) {  // Not init yet
     return;
   }
+  status_ = Status::OK();
   SeekToRestartPoint(num_restarts_ - 1);
   while (ParseNextIndexKey() && NextEntryOffset() < restarts_) {
     // Keep skipping