From 1fdf49c10edbc1f5544a75499c5a056b2ac01664 Mon Sep 17 00:00:00 2001
From: Andrew Kryczka <andrewkr@fb.com>
Date: Mon, 12 Oct 2020 13:43:52 -0700
Subject: [PATCH] Fix bug in pinned partitioned user key indexes

Backports part of 75d3b6fdf0aa1007c4d26382f65be0adf4519a37.
---
 HISTORY.md                  | 1 +
 table/iterator_wrapper.h    | 5 +++++
 table/two_level_iterator.cc | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/HISTORY.md b/HISTORY.md
index bce9de018..aa1cf8be6 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -2,6 +2,7 @@
 ## Unreleased
 ### Bug Fixes
 * Since 6.12, memtable lookup should report unrecognized value_type as corruption (#7121).
+* Fixed a bug in the following combination of features: indexes with user keys (`format_version >= 3`), indexes are partitioned (`index_type == kTwoLevelIndexSearch`), and some index partitions are pinned in memory (`BlockBasedTableOptions::pin_l0_filter_and_index_blocks_in_cache`). The bug could cause keys to be truncated when read from the index leading to wrong read results or other unexpected behavior.
 
 ## 6.12.4 (2020-09-18)
 ### Public API Change
diff --git a/table/iterator_wrapper.h b/table/iterator_wrapper.h
index 010a23abf..91487708b 100644
--- a/table/iterator_wrapper.h
+++ b/table/iterator_wrapper.h
@@ -149,6 +149,11 @@ class IteratorWrapperBase {
     return result_.value_prepared;
   }
 
+  Slice user_key() const {
+    assert(Valid());
+    return iter_->user_key();
+  }
+
  private:
   void Update() {
     valid_ = iter_->Valid();
diff --git a/table/two_level_iterator.cc b/table/two_level_iterator.cc
index a17d56df5..d967deff8 100644
--- a/table/two_level_iterator.cc
+++ b/table/two_level_iterator.cc
@@ -43,6 +43,10 @@ class TwoLevelIndexIterator : public InternalIteratorBase<IndexValue> {
     assert(Valid());
     return second_level_iter_.key();
   }
+  Slice user_key() const override {
+    assert(Valid());
+    return second_level_iter_.user_key();
+  }
   IndexValue value() const override {
     assert(Valid());
     return second_level_iter_.value();